{ "schema": "cie-topical-past-papers/answers-v1", "subject": "9700", "subject_name": "Biology", "generated": "2026-10-21", "coverage": { "question_records": 511, "available_mark_scheme_entries": 511, "unavailable_mark_scheme_entries": 0 }, "records": [ { "id": "9700-2021-m-42-q01", "question_id": "9700-2021-m-42-q01", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 predation / fishing ;\n2 food qualified ;\ne.g. competition / limited amount\n3 disease ;\n4 AVP ;\ne.g. idea that birth rate and death rate are roughly equal\n\n1(b) 1 organisms have changed over time ; 2\nany one from:\n2 ref. to natural selection / selective advantage for survival / survival of the fittest ;\n3 ref. to long period of time ;\n4 ref. to variation ;\n\n1(c) any three from: 3\n1 as the generation time increases, the rate of evolution decreases / relationship is inversely proportional / AW ; ora\n2 not linear / exponential / decreasing gradient ;\n3 (longer generation time) so less, reproduction / DNA replication ; ora\n4 ref. to fewer mutations ; ora\n5 idea of (so) less chance of evolution ; ora\nmp5 must be linked to mp3 or mp4\n© UCLES 2021 Page 6 of 22\n\n1(d) any three from: 3\n1 well adapted to their environment ;\n2 environment / selection pressures, stayed, constant / stable ; ora\n3 mutations qualified ;\ne.g. fewer / not selected for / low rate\n4 AVP ;\ne.g. no natural predators / cannot migrate / no separation of populations (for speciation to occur)\nQuestion Answer Marks", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p06.png", "../answer-assets/9700_m21_ms_42-p07.png" ] }, { "id": "9700-2021-m-42-q02", "question_id": "9700-2021-m-42-q02", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "2(a)(i) Canis ; 1\n\n2(a)(ii) any three from: 3\n1 decrease in biodiversity ;\n2 prey of grey wolf / herbivores, (may) increase in number ;\n3 (leads to) overgrazing ;\nA herbivores would decrease plant populations\n4 change in, ecosystem / habitat / food web ;\n5 change in genetic variation ;\n6 over many years ;\n© UCLES 2021 Page 7 of 22\n\n2(b) any two from: 2\n1 difficult to capture ;\n2 dangerous (to humans) ;\n3 large territory (so unlikely to recapture) ;\n4 migration ;\n5 may not mix with other wolves ;\n6 small, sample size / populations (so inaccurate) ;\n\n2(c)(i) (+)257 / 260 ; 1\n\n2(c)(ii) any three from: 3\n1 overall increase in grey wolf numbers ;\n2 decrease in Sierra Morena population ;\n3 alpine population is new population ;\n4 data quote ;\n5 increase in, territory / area, for, Iberian / Italian, populations ;\n6 AVP ;\ne.g. alpine population arose from, dispersal / migration, of Italian population\n© UCLES 2021 Page 8 of 22\n\n2(d)(i) any one from: 1\n1 compensation scheme (for loss of livestock) ;\n2 idea of protection of livestock ;\ne.g. build, fences / enclosures\n3 allow controlled culling (of wolves) ;\n4 move individual wolves to (wild) areas away from livestock ;\n\n2(d)(ii) any three from: 3\n1 reserves / national parks ;\n2 education / (public) awareness programmes ;\n3 research qualified ;\ne.g. habitat, diet, reproduction\n4 ban, hunting / trade (of wolf products) ;\n5 monitor populations ;\n6 AVP ;\nI ref. to zoos, captive breeding\n© UCLES 2021 Page 9 of 22", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p07.png", "../answer-assets/9700_m21_ms_42-p08.png", "../answer-assets/9700_m21_ms_42-p09.png" ] }, { "id": "9700-2021-m-42-q03", "question_id": "9700-2021-m-42-q03", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 8, "status": "available", "reason": null, "text": "3(a) any four from: 4\n1 gene(s) involved in production of carotene obtained ;\n2 from, another species / bacteria / daffodil / maize / rice ;\n3 ref. to use of named enzyme ;\ne.g. restriction enzyme / restriction endonuclease / (DNA) ligase\n4 ref. to plasmid / vector / gene gun ;\n5 ref. to recombinant DNA ;\n6 ref. to insertion of gene into rice, cells / embryos / genome / DNA / chromosome ;\n7 gene(s), expressed / transcribed, to produce enzyme(s) that make carotene ;\n8 AVP ;\ne.g. extra detail such as promoter\n© UCLES 2021 Page 10 of 22\n\n3(b) any four from: 4\n1 33–34 grams of genetically modified rice needed (to meet the RDA of a child) ;\n2 would help to prevent (childhood) blindness ;\n3 would help to prevent death (of children) ;\n4 (seeds) affordable / AW ;\n5 (seeds) scientifically proven to be safe ;\n6 (continuing to campaign would cause) waste of government money ;\n7 AVP ;\ne.g. benefits outweigh concerns\nplant-based GM (no GM animal welfare concerns)\nwould reduce the need for supplementing diets\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p10.png", "../answer-assets/9700_m21_ms_42-p11.png" ] }, { "id": "9700-2021-m-42-q04", "question_id": "9700-2021-m-42-q04", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "4(a)(i) 565nm ; 1\n\n4(a)(ii) 1 phycoerythrin does not absorb light above 590–600 (nm) ; 2\nA suitable value for absorption that answer the question\n2 (but) photosynthesis still takes place (above 590–600 nm) ;\nA suitable value for absorption that answer the question\n© UCLES 2021 Page 11 of 22\n\n4(a)(iii) any two from: 2\n1 accessory pigment ;\n2 absorbs light energy (up to 595 nm) ;\nR trap / capture\n3 (and) passes it to, primary pigment / reaction centre / chlorophyll a ;\n\n4(b)(i) chromatography ; 1\n\n4(b)(ii) any three from: 3\n1 calculate R value(s) ;\nf\n2 compare R values of pigments (in red algae and green plant) ;\nf\n3 find pigment present (on chromatogram) from red algae but absent from green plant\nor\nR value of phycoerythrin will not be the same as Rf values of pigments in green leaves ;\nf\n4 identify pigment using reference values (to confirm it is phycoerythrin) ;\n© UCLES 2021 Page 12 of 22", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p11.png", "../answer-assets/9700_m21_ms_42-p12.png" ] }, { "id": "9700-2021-m-42-q05", "question_id": "9700-2021-m-42-q05", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "5(a) 6\nion direction of movement of ion action resulting from movement of ion\nco-transport / secondary active transport, of,\nfrom lumen of proximal\namino acids / glucose\nNa+ convoluted tubule into proximal\nor\nconvoluted tubule cell\nosmosis of water ;\nK+ ; into guard cell opening of stoma(ta)\nNa+ ; into presynaptic knob depolarisation of presynaptic membrane\nCa2+ ; into presynaptic knob exocytosis of acetylcholine\nfrom intermembrane space into\nH+ ATP synthesis ;\nmatrix of mitochondrion\nbinds to troponin / troponin shape\nchanges / tropomyosin moves /\nfrom sarcoplasmic reticulum to actin binding site on myosin head exposed /\nCa2+\ncytoplasm of muscle fibre binding of myosin head to actin /\nallows power stroke /\nsarcomere contracts ;\n\n5(b)(i) Ca2+ / calcium ions ; 1\n\n5(b)(ii) to avoid wasting energy 1\nor\nidea of avoid closing, due to a single contact / by an object such as water drop ;\n\n5(b)(iii) exocytosis ; 1\n\n5(b)(iv) not enough, nitrogen / nitrate, in the soil 1\nor\npoor mineral content of the soil ;\nR nutrients\n© UCLES 2021 Page 13 of 22", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p13.png" ] }, { "id": "9700-2021-m-42-q06", "question_id": "9700-2021-m-42-q06", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "6(a) any five from: 5\n1 chemicals, stimulate / bind to / enter, (receptor cells) ;\n2 Na+ enters (receptor cells) via microvilli ;\n3 membrane depolarised ;\n4 ref. to receptor potential ;\n5 ref. to threshold ;\n6 voltage-gated Ca2+ channels open / Ca2+ ions enter, cytoplasm / cell ;\n7 vesicles (of neurotransmitter), move towards / fuse with, (cell surface) membrane ;\n8 exocytosis of neurotransmitter / AW ;\n9 neurotransmitter binds to receptor ;\n10 (receptor cell) acts as a transducer ;\n\n6(b) any two from: 2\n1 non-invasive / safe ;\n2 quick / immediate results / saves time / early detection ;\n3 can be done at home / no equipment ;\n4 cheap / cost effective ;\n© UCLES 2021 Page 14 of 22", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p14.png" ] }, { "id": "9700-2021-m-42-q07", "question_id": "9700-2021-m-42-q07", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "7(a)(i) R – (sister) chromatids ; 2\nS – centromere ;\n\n7(a)(ii) any three from: 3\n1 have same genes ;\nR same number of genes\n2 (genes at) same, loci / position on a chromosome ;\n3 same position of, S / centromere ;\n4 same length ;\n5 forms bivalent ;\n© UCLES 2021 Page 15 of 22\n\n7(a)(iii) 2\nG g G g\ntop 3\ndifferent\nH h H h ;\non each\npair\nI i I i\nJ J j j\nS S\nall same\nK K k k\n; on each\npair\nL L l l\nM M m m\n\n7(b) prophase 1 ; 1\n© UCLES 2021 Page 16 of 22\n\n7(c) any three from: 3\n1 homologous chromosomes / bivalents, align independently of each other ;\n2 at the, equator / metaphase plate ;\n3 idea that this leads to different combinations of chromosomes in the daughter cells ;\n4 results in new combinations of alleles ;\n5 AVP ;\ne.g. in humans 223 / 2n, different combinations\nQuestion Answer Marks", "source_pages": [ 15, 16, 17 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p15.png", "../answer-assets/9700_m21_ms_42-p16.png", "../answer-assets/9700_m21_ms_42-p17.png" ] }, { "id": "9700-2021-m-42-q08", "question_id": "9700-2021-m-42-q08", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 16, "status": "available", "reason": null, "text": "8(a)(i) A – label line pointing to mitochondrial matrix ; 1\n\n8(a)(ii) crista(e) ; 1\n\n8(a)(iii) any five from: 5\n1 folded (inner) membrane / many cristae ;\n2 forms large surface area ;\n3 (for) electron carriers / electron transport chain / ETC / cytochromes ;\n4 ref. to ATP synth(et)ase / ATP synthesis ;\n5 impermeable to, protons / hydrogen ions ;\n6 (so) allows, formation of proton gradient / high concentration of protons in intermembrane space ;\n7 proton pumps ;\n© UCLES 2021 Page 17 of 22\n\n8(b) DCPIP / methylene blue ; 2\nchanges, colour / blue to colourless, when, reduced / accepts electrons (from succinate) ;\n\n8(c)(i) any three from: 3\n1 rate of respiration increases (as succinate concentration increases) up to 1.0 mmol dm–3\nor\nmaximum rate at 1.0 mmol dm–3 ;\n2 rate of respiration higher at 37 °C than at 10 °C (in liver and muscle) ;\n3 rate of respiration higher in muscle than in liver (at both temperatures) ;\n4 comparative data quote to support mp2 or mp3 ;\n\n8(c)(ii) any three from: 3\nmuscles have higher rate of respiration because:\n1 respiration produces ATP ;\n2 muscle has higher need for, ATP / energy ; ora\n3 for muscle contraction\nor\nmuscle is more metabolically active / AW ;\n4 AVP ;\ne.g. shivering to maintain body temperature ;\n\n8(c)(iii) muscle, is contracted / generates heat / is more metabolically active / AW ; ora 1\n© UCLES 2021 Page 18 of 22", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p17.png", "../answer-assets/9700_m21_ms_42-p18.png" ] }, { "id": "9700-2021-m-42-q09", "question_id": "9700-2021-m-42-q09", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 15, "status": "available", "reason": null, "text": "9(a) any eight from: 8\nEukarya v Bacteria\n1 nucleus v no, nucleus / nuclear envelope ;\n2 linear DNA v circular DNA / plasmid ;\n3 histone proteins associated with DNA v no histone proteins ;\n4 (double) membrane-bound organelles v no membrane-bound organelles ;\nignore named organelles\n5 80S ribosomes v 70S ribosomes ;\n6 cell wall sometimes present v cell wall always present ;\n7 cell wall (if present) made of cellulose / chitin v cell wall made of peptidoglycans ;\n8 cells divide by mitosis v cells divide by binary fission ;\nI ref. to meiosis\n9 (can be) multicellular v unicellular ;\n10 AVP ;\ne.g. differences in flagellum structure\n© UCLES 2021 Page 19 of 22\n\n9(b) any seven from: 7\n1 botanic gardens ;\n2 research ;\n3 controlled named growing conditions ;\ne.g. light / water / nutrients / temperature\n4 propagation / named method ;\ne.g. cuttings / tissue culture / controlled pollination\n5 plant back to natural environment ;\n6 seed banks / collect seeds ;\n7 detail of seed storage ;\ne.g. low oxygen / low moisture / low temperature\n8 seeds regularly, tested for viability / re-stocked ;\nA description\n9 maintain genetic diversity / genetic material preserved / acts as a gene bank ;\n10 can be germinated prior to introduction back into natural habitat ;\n11 ref. to CITES ;\n12 ref. to (conservation) projects in situ / named example ;\ne.g. remove alien species / forestry project\n© UCLES 2021 Page 20 of 22", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p19.png", "../answer-assets/9700_m21_ms_42-p20.png" ] }, { "id": "9700-2021-m-42-q10", "question_id": "9700-2021-m-42-q10", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 15, "status": "available", "reason": null, "text": "10(a) any six from: 6\n1 analysis of biological data using computer software / AW ;\n2 databases of, gene / DNA / protein / amino acid, sequences ;\n3 ref. to large databases ;\n4 fast / accurate / efficient ;\n5 ref. to allows data to be, shared / pooled ;\n6 can predict, amino acid sequences / protein structure (from DNA sequence data) ;\n7 ref. to analytical tool ;\ne.g. BLAST\n8 ref. to comparisons ;\n9 used to find methods to control parasites ;\n10 named example of control ;\ne.g. vaccine\n11 AVP ;\ne.g. personalised medicine\nidentify new diseases\nref. common ancestor\nphylogenetic analysis\nbiodiversity / new species\n© UCLES 2021 Page 21 of 22\n\n10(b) any nine from: 9\n1 probes are, single-stranded DNA / ssDNA ;\n2 each probe is unique to a particular gene ;\n3 probes correspond to thousands of different genes ;\n4 extract mRNA ;\n5 mRNA used (as a template) to make cDNA ;\nR mRNA converted to cDNA\n6 by reverse transcription / using reverse transcriptase ;\n7 (c)DNA linked to fluorescent dye ;\n8 (c)DNA added to microarray ;\n9 (c)DNA, binds to / hybridises, to probes ;\n10 by complementary base pairing ;\n11 excess (c)DNA washed off ;\n12 exposed to, UV light / laser ;\n13 fluorescence shows the expressed genes / AW ;\n14 intensity of fluorescence shows level of gene expression ;\n© UCLES 2021 Page 22 of 22", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_42-p21.png", "../answer-assets/9700_m21_ms_42-p22.png" ] }, { "id": "9700-2021-m-52-q01", "question_id": "9700-2021-m-52-q01", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 22, "status": "available", "reason": null, "text": "1(a)(i) number of (different) species (of plant) / species richness ; 2\nabundance / number / frequency / population / density, of each species (of plant) ;\n\n1(a)(ii) ref. to trampling / trampled versus non-trampled ; 1\n\n1(b) any eight from: 8\n1 use, quadrat(s) / a (named type of) transect ;\n2 idea of sampling in the trampled and untrampled area ;\n3 ref. to, method of, random placement of quadrats / systematic sampling along the transect ;\n4 ref. to use of, same / stated, size (frame / point), quadrat ;\n5 method of identifying species ;\n6 ref. to a method of estimating abundance ;\n7 idea of taking care to note low growing / small / easy to miss, species ;\n8 idea of sampling at least 3 separate points in the open land and on the shortcut path / 3 different line transects ;\n9 repeat (whole investigation) at different times of, year / seasons ;\n10 calculate / use, Simpson’s index (of diversity) ;\n11 plants causing irritation / allergy and wearing, gloves / protective clothing\nor\npollen causing, hay fever / allergy, and wearing mask or taking medication\nor\nref. to environmental hazard related to its risk and wearing, suitable shoes / protective clothing or suitable mitigation ;\n© UCLES 2021 Page 6 of 9\n\n1(c)(i) support: 2\n(all) the times, for path / trampled area, are, longer / higher / slower (than untrampled) / ora ;\ndo not support:\nidea of no information about soil air spaces ;\n\n1(c)(ii) S = 2.8 ; 2\nM\n95% confidence interval = 68.1 / 68.2, to 79.5 / 79.4 ;\n\n1(c)(iii) any two from: 2\n1 95%, probability / confidence that / chance that, the, true / population / parametric / actual, mean, lies within these limits\n;\n2 the difference between means is (likely to be) significant (at p<0.05 because there is no overlap between 95% CI for\nuntrampled and trampled) ;\n3 idea that the narrower CI (in the untrampled area), the closer the calculated mean is to the true mean / ora ;\n\n1(d)(i) any two from: 2\n1 idea of using a grid and tracing outline / using transparent grid over leaf ;\n2 idea of systematic counting of squares fully and more than half covered ;\n3+4 AVP ; ;\n\n1(d)(ii) there is a negative correlation 1\nor\nas time taken for (10 cm3) of water to drain through decreases, leaf surface area increases / ora ;\n\n1(d)(iii) 1 working at, p = 0.05 / p<0.05 ; 2\n2 correlation / relationship, is, significant / not due to chance, as calculated r (0.455) is greater than (critical value of)\ns\n0.447 ;\n© UCLES 2021 Page 7 of 9", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_52-p06.png", "../answer-assets/9700_m21_ms_52-p07.png" ] }, { "id": "9700-2021-m-52-q02", "question_id": "9700-2021-m-52-q02", "subject": "9700", "year": 2021, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 8, "status": "available", "reason": null, "text": "2(a)(i) time taken for, indigo carmine / solution / indicator, to, turn blue / change colour ; 1\n\n2(a)(ii) any one from: 1\nnumber / mass, of beads (of immobilised cells) ;\nsize / surface area, of beads ;\nconcentration of alginate ;\ndensity / number, of cells / protoctists ;\nambient / background / AW, light (intensity) ;\npH ;\nconcentration of indicator ;\nspecies / type, of protoctist / unicell / AW ;\n\n2(b)(i) 2.55 ; 1\n\n2(b)(ii) any three from: 3\n1 idea that increasing, hydrogencarbonate / carbon dioxide, (concentration) increases, the rate of photosynthesis / the\nrate / photosynthesis / the rate of reaction / ora ;\n2 idea that increasing, light intensity, increases, the rate of photosynthesis / the rate / photosynthesis / the rate of\nreaction / ora ;\n3 ref. to when carbon dioxide / hydrogencarbonate, is a limiting factor using information from Table 2.1 ;\n4 ref. to when light is a limiting factor using information from Table 2.1 ;\n© UCLES 2021 Page 8 of 9\n\n2(b)(iii) any two from: 2\n1 idea of, (small) range / number / AW, of different concentrations of, (sodium hydrogencarbonate / carbon dioxide)\nsolution ;\n2 idea of, (small) range / number / AW, of different light intensities ;\n3 idea of outside air has not been excluded so change in colour may not be due only to oxygen produced ;\n4 idea that colour change is, subjective / difficult to see ;\n5 idea that only, one species / a protoctist / a unicell, is tested (so may not be valid for all species / types, of\nphotosynthetic organisms ;\n© UCLES 2021 Page 9 of 9", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2021-March/ms/9700_m21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-march/9700_m21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m21_ms_52-p08.png", "../answer-assets/9700_m21_ms_52-p09.png" ] }, { "id": "9700-2021-mj-41-q01", "question_id": "9700-2021-mj-41-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "1(a)(i) any two from: 2\n1 absorb / harvest / capture / trap, light / photons ;\n2 (to) excite electrons ;\n3 (for, cyclic / non-cyclic) photophosphorylation / electron transport chain ;\n4 accessory pigment passes energy to, primary pigment / reaction centre ;\n5 (pigments) form a, light harvesting cluster / photosystem / PSI / PSII ;\n\n1(a)(ii) thylakoid membrane(s) / granum / grana / lamella(e) ; 1\n\n1(a)(iii) chromatography ; 1\n\n1(b)(i) 1 (from 0.25) to 1.00 (mol dm–3), concentration / CO , is limiting factor 3\n2\nor\nat / >, 1.00 (mol dm–3), concentration / CO , no longer limiting factor ;\n2\n2 at / >, 1.00 (mol dm–3), light intensity / temperature, is limiting factor ;\n3 CO , needed / used, for Calvin cycle / for light independent stage\n2\nor\nCO ,reacts with / fixed by, RuBP ;\n2\n\n1(b)(ii) little / no, photosynthesis ; 2\n(aerobic) respiration uses oxygen ;\n\n1(b)(iii) any three from: 3\n1 to control a variable / to ensure a fair test / so CO is the only variable ;\n2\n2 low, temperature / kinetic energy, decreases, rate / reaction / photosynthesis / O production / O increase ;\n2 2\n3 low, temperature / kinetic energy, decreases, (named) enzyme-substrate, collisions / complexes ;\n4 low(er) temperature, is a limiting factor / may limit rate ;\n5 high, temperature / kinetic energy, decreases, rate / reaction / photosynthesis / O production / O increase ;\n2 2\n6 high, temperature / kinetic energy, denatures (named) enzyme(s) ;\n7 high / increased, temperature, causes / increases, photorespiration ;\n© UCLES 2021 Page 6 of 16", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p06.png" ] }, { "id": "9700-2021-mj-41-q02", "question_id": "9700-2021-mj-41-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\nidea of synthesis from smaller units\n1 DNA replication / transcription ;\n2 to, make / build up, (named) protein ;\n3 to, make / build up, (named), lipid / triglyceride / phospholipid ;\n4 to, make / build up, (named) carbohydrate / polysaccharide ;\n5 phosphorylation ;\n\n2(a)(ii) any three from: 3\n1 phosphorylates glucose\nor\nglucose  glucose / fructose / hexose, phosphate ;\n2 second phosphorylation\nor\nglucose / fructose / hexose, phosphate  fructose / hexose, bi(s)phosphate ;\n3 so glucose cannot leave the cell ;\n4 activates / increases energy of / decreases stability of, glucose ;\n\n2(b)(i) any three from: 3\ndecreased production of ATP\n1 smaller / less steep, proton gradient ;\n2 few(er) protons go through, ATP synth(et)ase / stalked particle ;\nincreased lipid metabolism\n3 use / burn / respire, body fat / lipid stores ;\n4 as less ATP made from, glucose / food ;\n\n2(b)(ii) any two from: 2\n1 more / faster / increased, (rate of) glycolysis ;\n2 oxygen, decreased / used faster / shortage ;\n3 (so) more / increased, anaerobic respiration ;\n\n2(b)(iii) any one from: 1\nenergy from, reduced NAD / ETC, released as heat ;\nenergy not used to join ADP and Pi so released as heat ;\n© UCLES 2021 Page 7 of 16", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p07.png" ] }, { "id": "9700-2021-mj-41-q03", "question_id": "9700-2021-mj-41-q03", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 11, "status": "available", "reason": null, "text": "3(a)(i) any three from: 3\n(individuals / organisms / members of a species are similar / same)\n1 morphologically ;\n2 physiologically ;\n3 biochemically ;\n4 genetically ;\n5 ecologically / occupy same niche ;\n6 behaviourally ;\n7 can (inter)breed to form fertile offspring ;\n8 reproductively isolated (from other species) ;\n9 share, an evolutionary lineage / recent common ancestor ;\n10 share a, binomial / Linnaean, name ;\n\n3(a)(ii) domain: Eukarya ; 2\nkingdom: Animalia ;\n\n3(a)(iii) any two from: 2\n1 classification / taxonomy, reflects / shows / depends on, evolutionary / phylogenetic, relationships ;\n2 organisms / species, that, are closely related / share recent common ancestor, should be classified together ;\n3 help identify, larger taxonomic groups / orders / families / genera ;\n4 AVP ;\n\n3(b)(i) (1478 × 103 × 2 =) 304 468 ; 1\n\n3(b)(ii) any three from: 3\n1 to, store / analyse / process ;\n2 large quantity of data ;\n3 to, compare / match, (many) sequences ;\n4 to, calculate / measure / quantify, (percentage), similarity / difference ;\n5 ref. to fast / accurate / efficient ;\n© UCLES 2021 Page 8 of 16", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p08.png" ] }, { "id": "9700-2021-mj-41-q04", "question_id": "9700-2021-mj-41-q04", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "4(a) any five from: 5\n1 (named) restriction, enzyme / endonuclease ;\n2 cut / fragment, DNA ;\n3 produced by / present in, bacteria / archaea / prokaryotes\nor\nto defend against, viruses / (bacterio)phages ;\n4 (DNA) ligase ;\n5 joins DNA / forms phosphodiester bonds / seals sugar-phosphate backbone ;\n6 during DNA, repair / replication\nor\njoins Okazaki fragments ;\n7 reverse transcriptase ;\n8 forms / makes, (c)DNA from mRNA (template) ;\n9 produced by / present in, retroviruses ;\n10 DNA / Taq, polymerase ;\n11 replicates / copies, DNA (at high temperatures) ;\n12 produced by / present in, Thermus aquaticus ;\n\n4(b)(i) any three from: 3\n1 increased / higher / more, yield / production / harvest / food ;\n2 increased / higher / better, quality of, produce / crops / food ;\n3 decreased / lower / less, insecticide / pesticide, needed / used ;\n4 decreased / lower / less, fuel use / CO emissions ;\n2\n5 potential for, set-aside / conservation areas (as less land needed for crops) ;\n6 (described) comparative economic benefit ;\n\n4(b)(ii) any two from: 2\n1 people in other (named) continents eat GM, food / crops ;\n2 GM, food / crops, already in (European) food chain ;\n3 ref. to economic benefit of reducing GM (animal food) imports ;\n\n4(b)(iii) 1 do not know / need to know, total crop area / non-GM crop area ; 2\n2 so can work out, percentage / fraction, of, GM / non-GM ;\n© UCLES 2021 Page 9 of 16", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p09.png" ] }, { "id": "9700-2021-mj-41-q05", "question_id": "9700-2021-mj-41-q05", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "5(a)(i) any three from: 3\n1 wider / thicker / larger diameter  increases / higher, speed ;\n2 large(r) membrane surface area so more ion movement ;\n3 myelin  increases / faster / higher, speed ;\n4 saltatory conduction (in myelinated) ;\n5 pairwise data comparison ;\n\n5(a)(ii) any one from: 1\n1 impulses, for touch / in Aβ neurones, travel faster ;\n2 (Aβ neurones) inhibit, spinal cord / relay / projection, neurones ;\n3 AVP ;\n\n5(b)(i) any four from: 4\n1 endorphins bind to (endorphin) receptors ;\n2 stop, calcium ions / Ca2+, entering presynaptic knob ;\n3 no / fewer, vesicles, move towards / fuse with, (presynaptic) membrane ;\n4 no / less, acetylcholine / ACh, released ;\n5 no / less, binding of ACh to postsynaptic receptors ;\n6 no / less, depolarisation of postsynaptic, neurone / membrane ;\n7 no / fewer, action potentials / impulses, to, pain centre / brain ;\n\n5(b)(ii) any one from: 1\n1 (drug) dependency / addiction / tolerance ;\n2 (drug) side-effects ;\n3 expensive ;\n4 work more slowly ;\n© UCLES 2021 Page 10 of 16", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p10.png" ] }, { "id": "9700-2021-mj-41-q06", "question_id": "9700-2021-mj-41-q06", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "6(a) 4\nresponse explanation\nblood vessels near the surface of the skin constrict\nless heat lost as, less / slower, blood (flow) at, skin / surface ;\n(narrow)\nshivering occurs muscle contraction, creates / generates / produces, heat ;\nhairs rise trapped air, insulates / reduces thermal gradient ;\nreduction in the production of sweat to stop / decrease, heat loss by evaporation ;\n\n6(b) decrease / less, surface area to, conserve / retain heat 1\nor\ndecrease / less, surface area so less heat lost ;\n\n6(c)(i) any three from: 3\n1 Sitatunga’s (core / body) temperature (fairly) constant ;\n2 Nile monitor’s / lizard’s, (core / body) temperature rises as environmental temperature rises ;\n3 figures for two animals at one temperature with units\nor\none animal at two temperatures with units ;\n4 AVP ;\n\n6(c)(ii) problem with, catching prey / feeding / avoiding predation ; 1\n\n6(d) 1 ref. to set point / norm(al) / ideal value ; 3\n2 rise / fall / change / fluctuation ;\n3 reversed / corrected / counter-acted ;\n© UCLES 2021 Page 11 of 16", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p11.png" ] }, { "id": "9700-2021-mj-41-q07", "question_id": "9700-2021-mj-41-q07", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) codominant 3\n1 both (alleles), affect / seen in / expressed in / contribute to (phenotype) ;\n2 in heterozygote ;\nrecessive\n3 affects / seen in / expressed / contributes to, (phenotype) (only) when dominant (allele) absent / in homozygote ;\n\n7(b) 3\nparental phenotype A B\nparental genotype IA Io IB Io\ngametes IA Io IB Io ;\noffspring genotype IA IB IA Io IB IO Io Io ;\noffspring phenotype AB A B O ;\n\n7(c) any three from: 3\n1 males / men / boys, are, XY / have (only) one X chromosome ;\n2 man / father, passes Y to, male offspring / son ;\n3 man / father, does not pass X to, ♂ offspring / son ;\n4 man / father, passes, X / mutation, to, female offspring / daughter ;\n5 woman / mother, passes X / mutation, to, male offspring / son ;\n© UCLES 2021 Page 12 of 16", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p12.png" ] }, { "id": "9700-2021-mj-41-q08", "question_id": "9700-2021-mj-41-q08", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "8(a)(i) artificial selection ; 1\n\n8(a)(ii) any five from: 5\n1 (humans) choose / cross / breed from, females / cows / cattle, with, good / high, milk yield ;\n2 (humans) choose / cross / breed from, males / bulls, with, mother / sisters / daughters, with, good / high, milk yield ;\n3 (humans) choose / cross / breed from, desirable offspring ;\n4 continue / repeat, for (several) generations ;\n5 allele(s) for, high milk yield / desired trait, passed on ;\n6 increase in frequency of, good / best / high yield, allele(s) ;\n7 artificial insemination / A.I. ;\n8 AVP ;\n\n8(b) any three from: 3\n1 mean / mode / median / average / intermediate, selected against / not favoured / less fit / die ;\n2 (both) extremes, selected for / favoured / more fit / survive / reproduce ;\n3 bimodal distribution ;\n4 diversifying selection ;\n5 causes / maintains, polymorphism / genetic diversity ;\n© UCLES 2021 Page 13 of 16", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p13.png" ] }, { "id": "9700-2021-mj-41-q09", "question_id": "9700-2021-mj-41-q09", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 15, "status": "available", "reason": null, "text": "9(a) any eight from: 8\n1 vary / different / range of, glucose / fructose, concentrations ;\n2 control / same, volume of yeast (suspension) ;\n3 control / same, volume of glucose (solution) ;\n4 control / same, volume / concentration, of indicator (solution) ;\n5 control temperature (between 20–45oC) ;\n6 oil layer to exclude, air / oxygen ;\n7 indicator turns from blue (start / oxidised) to colourless (end / reduced) ;\n8 due to, hydrogen atoms / H+ / electrons, from, glycolysis / dehydrogenation / respiration ;\n9 time how long it takes for colour change OR fix time interval and measure with colorimeter ;\n10 repeat experiment ;\n11 calculate mean(s) ;\n12 graph with glucose concentration (on x axis) and, time taken / % absorbance / % transmission / rate (on y) ;\n13 rate is 1/t ;\n14 AVP ;\n© UCLES 2021 Page 14 of 16\n\n9(b) any seven from: 7\nboth\n1 occur in cytoplasm ;\n2 (only) involve glycolysis ;\n3 make, 2 (net) / small amount of, ATP ;\n4 regenerate NAD (from NADH) ;\ncomparison\nmammalian tissue yeast cells\n5 H acceptor / reduction of pyruvate / pyruvic acid ethanal\n6 (end) product lactate / lactic acid ethanol\n7 no, CO decarboxylation CO\n2 / 2\n8 (enzyme) lactate dehydrogenase ethanol dehydrogenase\n9 steps / stages one / 1 two / 2\n10 (process) reversible irreversible\n© UCLES 2021 Page 15 of 16", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p14.png", "../answer-assets/9700_s21_ms_41-p15.png" ] }, { "id": "9700-2021-mj-41-q10", "question_id": "9700-2021-mj-41-q10", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 15, "status": "available", "reason": null, "text": "10(a) any eight from: 8\n1 named geographical barrier ; e.g. river / mountain / sea / lake\n2 population, separated / divided (into two) ;\n3 no, mating / breeding / gene flow, between, populations / groups ;\n4 different (named), selection pressures / environments / conditions ;\n5 different mutations ;\n6 individuals with beneficial alleles, are selected for / survive / reproduce / have a selective advantage ;\n7 genetic drift / founder effect ;\n8 change in, allele frequency / gene pool ;\n9 over a long time / many generations ;\n10 can no longer (successfully), interbreed / reproduce / produce fertile offspring, with, old / original / other, population /\nspecies ;\n11 allopatric (speciation) ;\n\n10(b) any seven from: 7\n1 environment changes ;\n2 species cannot adapt (fast enough) ;\n3 climate / temperature / sea level, change ;\n4 extinct species / species at risk ;\n5 competition / predation / disease, from, new / introduced / alien / invasive, species ;\n6 extinct species / species at risk ;\n7 (named) habitat, degradation / loss ;\n8 extinct species / species at risk ;\n9 hunting by humans / poaching / (over)fishing ;\n10 extinct species / species at risk ;\n11 AVP ;\n12 extinct species / species at risk ;\n© UCLES 2021 Page 16 of 16", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_41-p16.png" ] }, { "id": "9700-2021-mj-42-q01", "question_id": "9700-2021-mj-42-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) A – sodium potassium pump ; CON if channel mentioned 3\nB – potassium ions ; A K+\nD – sodium ions ; A Na+\nmax 2 if no ref. to ions\n\n1(a)(ii) ATP ; 1\n\n1(b) any five from: 5\ndrugs could be in any order\ncurare\n1 less / no, ACh binds to receptors ; I neurotransmitter\n2 fewer / no, (ligand gated) Na+ channels open\nor\nfewer / no, Na+ can enter sarcomere / sarcoplasm\nor\nno / less, depolarisation of, sarcolemma / muscle cell membrane ;\nnerve gas\n3 no / less, ACh broken down\nor\nACh remains bound to receptor ;\n4 (ligand gated) Na+ channels remain open / Na+ continue to enter post synaptic neurone\nor\npermanent / AW, depolarisation (of post synaptic membrane) ; A sarcolemma\nalcohol\n5 no / less, binding of, neurotransmitter / ACh, to receptors ;\n© UCLES 2021 Page 5 of 22\n\n1(b) 6 fewer / no, (ligand gated) Na+ channels open\nor\nfewer / no, Na+ can enter post synaptic neurone\nor\nno / less, depolarisation (of post synaptic membrane) ; A sarcolemma\nQuestion Answer Marks", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p05.png", "../answer-assets/9700_s21_ms_42-p06.png" ] }, { "id": "9700-2021-mj-42-q02", "question_id": "9700-2021-mj-42-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\n1 ref. to muscle fibre / sarcomere, contraction ;\n2 active transport of (named), ion / molecule\nor\nactive transport (of substance) against concentration gradient ;\n3 movement of, vesicles / organelles, through cytoplasm / described ;\n4 exocytosis of named substance ;\n5 endocytosis / phagocytosis ;\n6 spindle fibre / chromosome / chromatid, (movement) during, mitosis / meiosis ;\n7 cilia / flagella, wafting / beating / AW ; I movement\n© UCLES 2021 Page 6 of 22\n\n2(a)(ii) 150 750 2\ncorrect working ; e.g. =750 then\n0.2 24\nor\n150 6.25\n=6.25 then\n24 0.2\nor\n149.8 749\n=749 then\n0.2 24\n31 ;\n\n2(a)(iii) (respiration) oxidative phosphorylation ; 2\n(photosynthesis) photophosphorylation / light dependent stage ;\n\n2(b)(i) 1 reduces ATP synthesis / less ADP reacts with P ; 3\ni\nany two from:\n2 protons diffuse through thermogenin ;\n3 proton gradient reduced / reduces concentration of H+ in intermembrane space ;\n4 fewer protons pass through ATP synthase ;\n\n2(b)(ii) any three from: 3\n1 adrenaline binds to receptor on the cell surface membrane (of brown fat cells) ;\n2 G-protein / adenyl(yl) cyclase, activated ;\n3 ref. to cAMP / second messenger, (is formed) ;\n4 ref. to enzyme cascade / signal amplification / activation of kinase / signalling cascade ;\n5 activation of lipase by phosphorylation ;\n© UCLES 2021 Page 7 of 22", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p06.png", "../answer-assets/9700_s21_ms_42-p07.png" ] }, { "id": "9700-2021-mj-42-q03", "question_id": "9700-2021-mj-42-q03", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "3(a)(i) any three from: 3\n1 multicellular ;\n2 have, specialised cells / tissues / organs ;\n3 heterotrophic / described ;\n4 ref. to nervous system ;\n5 vacuoles / vesicles, are, small / temporary / not permanent ;\n6 are eukaryotes / have eukaryotic cells ;\n7 detail of eukaryote ; e.g. nucleus / (named) membrane-bound organelle / 80s ribosomes\n8 ref. to mobility ;\n\n3(a)(ii) any three from: 3\n1 records / assesses, biodiversity ;\n2 so conservation decisions can be made / AW ;\n3 example of conservation action 1 ;\n4 example of conservation action 2 ;\ne.g. (IUCN) red list of threatened species / identifying endangered species\n(CITES) regulation of trade\nref. assisted reproduction or ref. captive breeding\nseed banks\nplace in, zoos / national parks / marine parks / botanical gardens\n5 (taxonomic hierarchy is) internationally, recognised / standardised / AW ;\n© UCLES 2021 Page 8 of 22\n\n3(a)(iii) any two from: 2\n1 (yes because as number of species has increased) biodiversity has increased ;\n2 (idea of no because) numbers of new species that are being discovered are greater than the numbers of species\nbecoming extinct ;\n3 (idea of no because) does not assess number of individuals in a species ;\n4 AVP ; e.g. some species only exist in captivity\n\n3(a)(iv) insects 2\n1024945(×100 )\n;\n1438805\n71 ;\necf – accept 1 mark if wrong data chosen\ne.g.\ninsects 1024945(×100 )=86\narthropods 1191770\narthropods 1191770 (×100 )=83\nanimals 1438805\n\n3(b)(i) any two from: 2\n1 habitat loss / habitat fragmentation / urbanisation / building / deforestation ;\n2 insecticides / pesticides / farming / agriculture / fertilizers ; I pollution\n3 new / increase in, predators / diseases / parasites ;\n4 food shortage / increased competition (for food) ;\n© UCLES 2021 Page 9 of 22\n\n3(b)(ii) any two from: 2\n1 Bt toxin (only) kills, specific insects / insects that feed on the crops ;\n2 reduces use of, insecticides / pesticides ;\n3 idea that insects survive to pollinate plants ;\nQuestion Answer Marks", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p08.png", "../answer-assets/9700_s21_ms_42-p09.png", "../answer-assets/9700_s21_ms_42-p10.png" ] }, { "id": "9700-2021-mj-42-q04", "question_id": "9700-2021-mj-42-q04", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "4(a) diabetes: 2\ninsulin from (GM) bacteria ; A ref to, yeast / animal cells\nsingle gene disorder:\ngene therapy\nor\ninsert, functional / normal / dominant, allele into, target / somatic / stem, cells or genome ; A gene\nR replacing one allele with another\n© UCLES 2021 Page 10 of 22\n\n4(b)(i) any four from: 4\nvalid\n1 GM spinach decreases number of, bacteria / E.coli\nor\nGM spinach has lowest number of, bacteria / E.coli ;\n2 at all times (meat is stored)\nor\nthe longer the time stored the more effective it is\nor\nmost effective after 72 hours ;\n3 data quote comparing no treatment or buffer alone with GM spinach extract at stated time ;\ntime / hrs no treatment buffer alone buffer plus GM spinach\n1 3.7–3.8 3.8–3.9 1.4–1.5\n24 3.2–3.3 3.5–3.6 0.5–0.6\n72 2.6–2.7 3.3–3.4 0.1–0.2\nnot valid\n4 no treatment / buffer alone, (also) decrease number of, bacteria / E.coli\nor\nGM spinach does not kill all, bacteria / E.coli ;\n5 meat should not normally be left at 10°C\nor\npeople unlikely to eat meat left at, 10°C / for 72 hours ;\n6 does not test effect on people / AW ;\n© UCLES 2021 Page 11 of 22\n\n4(b)(ii) any three from: 3\n1 may alter, taste / texture / quality, of meat ;\n2 may be unsafe for humans / allergies / side effects ;\n3 may harm, gut / beneficial, bacteria\nor\nmay increase growth of, non-colicin sensitive / other, bacteria ;\n4 contaminate food labelled as organic / AW ;\n5 E.coli / bacteria, may develop resistance to, (spray / colicins) ;\nR GM spray / colicins, cause mutation\n6 AVP ; e.g. may decrease food hygiene practices in, meat factories / abattoirs / restaurants / food outlets ;\nQuestion Answer Marks", "source_pages": [ 10, 11, 12 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p10.png", "../answer-assets/9700_s21_ms_42-p11.png", "../answer-assets/9700_s21_ms_42-p12.png" ] }, { "id": "9700-2021-mj-42-q05", "question_id": "9700-2021-mj-42-q05", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "5(a)(i) mark first two answers 2\nATP ;\nreduced NADP ; A NADPH\n\n5(a)(ii) any two from: 2\n1 an accessory pigment ;\n2 absorb, light (energy) / photons ; A harvest I trap / capture\n3 pass on energy to, primary pigment / chlorophyll a / reaction centre ;\n4 AVP ; e.g. idea of extending the range of light wavelengths absorbed / absorbs wavelengths not absorbed by primary\npigment\n© UCLES 2021 Page 12 of 22\n\n5(b) 100 ; 1\n\n5(c)(i) 1 0 – 400 ; A up to 400 I units 3\nany two from:\n2 temperature / concentration of carbon dioxide, becomes the limiting factor ;\n3 (at a lower than optimum temperature)\nless kinetic energy so fewer collisions between rubisco and CO\n2\nor\na lower temp will limit the rate of (named) enzyme-controlled reactions ;\n4 (with a lower than optimum CO concentration) less fixation of CO / AW ;\n2 2\n5 all, enzymes / processes, in photosynthesis, already at, highest rate / optimum\nor\nmaximum amount of light is being absorbed (by the pigments) ;\n\n5(c)(ii) any three from: 3\n1 different wavelengths of light absorbed by different pigments ;\n2 red light is absorbed the most ;\n3 green light is, absorbed less / reflected ;\n4 shorter the wavelength the greater the energy / red light has more energy (than blue light) ; ora\n5 the more, light / energy, absorbed the more, light dependent reaction / photophosphorylation, occurs ; ora\n© UCLES 2021 Page 13 of 22", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p12.png", "../answer-assets/9700_s21_ms_42-p13.png" ] }, { "id": "9700-2021-mj-42-q06", "question_id": "9700-2021-mj-42-q06", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) (glyco / lipo) protein ; 1\n\n6(a)(ii) blood ; 1\n\n6(b) glycogenolysis / described ; 2\ngluconeogenesis / described ; e.g. glucose from, amino acids / fatty acids\n\n6(c) to reduce ingestion of food 1\nor\nbinds to receptor(s) in brain ;\n\n6(d) any three from: 3\n1 change in a parameter ;\n2 detected by receptor ;\n3 coordination / described ;\n4 (corrective) action taken by effector ;\n5 return to, set point / norm / optimum ;\n© UCLES 2021 Page 14 of 22\n\n6(e) any two from: 3\n1 frameshift / described ;\n2 different primary structure / shortened polypeptide ;\n3 TF non-functional / TF cannot bind to, DNA / promoter\nor\nTF not produced ;\n4 gene coding for GLP-1 not expressed ;\nplus\n5 less / no, GLP-1, produced / secreted ;\nQuestion Answer Marks", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p14.png", "../answer-assets/9700_s21_ms_42-p15.png" ] }, { "id": "9700-2021-mj-42-q07", "question_id": "9700-2021-mj-42-q07", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "7(a) allele – variety / form, of a gene ; 2\ndominant –(allele) always expressed / always has effect on the phenotype / expressed in heterozygote / has effect on the\nphenotype of heterozygote ;\n© UCLES 2021 Page 15 of 22\n\n7(b)(i) 5\ndouble homozygous\nwild type parent\nrecessive parent\nparental\nred eye, long wing purple eye, vestigial wing ;\nphenotype\nparental\nRrNn rrnn ;\ngenotype\noffspring\noffspring red eye, purple eye, red eye, purple eye,\n;\nphenotype long wing vestigial wing vestigial wing long wing\noffspring\nRrNn rrnn Rrnn rrNn ;;\ngenotype\nnumbers of\n1339 1195 151 154\noffspring\noffspring genotypes – 4 correct = 2 marks, 3 correct = 1 mark\nallow short wing for vestigial wing\nallow alleles in any order in genotypes\nignore brackets and circles around alleles\n© UCLES 2021 Page 16 of 22\n\n7(b)(ii) any three from: 3\n1 (two) genes are linked / autosomal linkage\nor\nalleles inherited together ;\n2 no, independent / random, assortment ;\n3 large numbers of parental type offspring / small numbers of recombinant offspring ;\n4 recombinants due to crossing over ;\n5 during, meiosis / prophase 1 / gamete formation ;\nQuestion Answer Marks", "source_pages": [ 15, 16, 17 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p15.png", "../answer-assets/9700_s21_ms_42-p16.png", "../answer-assets/9700_s21_ms_42-p17.png" ] }, { "id": "9700-2021-mj-42-q08", "question_id": "9700-2021-mj-42-q08", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "8(a) 1 different alleles at a single gene locus have small effects (on the phenotype) ; 3\n2 different genes may have an, additive / combined, effect (on the phenotype) ;\n3 ref. to multiple genes / polygenes / description ;\n\n8(b) any two from: 2\n1 quantity / availability, of, food / nutrients ; A competition for food\n2 quality of food / malnutrition ;\n3 disease ;\n4 temperature ;\n© UCLES 2021 Page 17 of 22\n\n8(c) any four from: 4\n1 humans apply selection pressure ;\n2 select parents that show desired characteristic ; R gene / allele\n3 breed these parents together ; R IVF ignore AI\n4 select offspring with desired characteristics ;\n5 breed selected offspring ;\n6 repeating over many generations ;\n7 AVP ; e.g. some outbreeding required to avoid, inbreeding depression / combining harmful recessive alleles\n© UCLES 2021 Page 18 of 22", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p17.png", "../answer-assets/9700_s21_ms_42-p18.png" ] }, { "id": "9700-2021-mj-42-q09", "question_id": "9700-2021-mj-42-q09", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 15, "status": "available", "reason": null, "text": "9(a) any nine from: 9\n1 (function is) to make ATP ;\n2 ref. to double membrane / outer and inner membrane / envelope ;\ninner membrane\n3 folded / cristae, to increase / for large, surface area ;\n4 has, ATP synthase / stalked particles ;\n5 has, ETC / carrier (proteins) / cytochromes ;\n6 (site of) oxidative phosphorylation / chemiosmosis ;\n7 impermeable to protons ;\nintermembrane space\n8 has low pH / high concentration of protons ;\n9 protons pumped into intermembrane space ;\n10 proton gradient between intermembrane space and matrix\nor\nprotons diffuse from intermembrane space to matrix ;\nmatrix\n11 contains (co)enzymes for, link reaction / the Krebs cycle ;\nouter membrane\n12 permeable to, pyruvate / reduced NAD / oxygen ;\n13 AVP ; e.g. ribosomes / DNA, involved in protein synthesis\n© UCLES 2021 Page 19 of 22\n\n9(b) any six from: 6\n1 aerenchyma ;\n2 in stem and roots ;\n3 help oxygen to, move / diffuse, to, roots / submerged parts ;\n4 shallow roots ;\n5 air (film) trapped on underwater leaves / described ;\n6 greater internode growth\nor\nleaves or flowers grow above water level ;\n7 (growth regulated by) gibberellin / ethene ;\n8 anaerobic respiration, in roots / underwater / when submerged ; A alcoholic fermentation\n9 tolerant to high ethanol (concentration) ;\n10 ref. to ethanol / alcohol, dehydrogenase ;\n© UCLES 2021 Page 20 of 22", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p19.png", "../answer-assets/9700_s21_ms_42-p20.png" ] }, { "id": "9700-2021-mj-42-q10", "question_id": "9700-2021-mj-42-q10", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 15, "status": "available", "reason": null, "text": "10(a) any nine from: 9\ngene mutation\n1 base substitution ;\n2 (often) does not have a significant effect on phenotype / silent mutation ;\n3 base, insertion / deletion leads to, frame shift / described ;\n4 (so) has significant effect on phenotype ;\n5 change in, primary structure / amino acid sequence / polypeptide made ;\n6 change in, tertiary structure / 3D shape / folding ;\n7 loss of function in protein or enzyme / example described ;\n8 (premature) stop codon ;\nHuntinton’s disease\n9 (mutant allele) is dominant ;\n10 HD / dominant, allele has more repeats of base triplet CAG (than normal) ;\n11 heterozygote will have disease ;\n12 brain cells die more rapidly (than normal) / brain degeneration ;\n13 involuntary movements / mental deterioration or described / mood changes ;\n14 onset in middle age / idea that no change in phenotype in earlier life ;\n15 AVP ; e.g. greater number of CAG repeats affects, earlier onset / severity of disease\n© UCLES 2021 Page 21 of 22\n\n10(b) any six from: 6\n1 DELLA proteins inhibit, transcription factor / PIF;\n2 gibberellin binds to receptor ;\n3 in aleurone layer ;\n4 ref. to enzyme involved ;\n5 DELLA proteins broken down ;\n6 TF / PIF, binds to promoter region (of DNA) ;\n7 transcription of gene coding for amylase / AW ;\n8 ref. to translation (leading to amylase production) ;\n© UCLES 2021 Page 22 of 22", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_42-p21.png", "../answer-assets/9700_s21_ms_42-p22.png" ] }, { "id": "9700-2021-mj-43-q01", "question_id": "9700-2021-mj-43-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "1(a) A – binding site ; 4\nB – tropomyosin ;\nC – troponin ;\nD – myosin head ; A ATPase\n\n1(b) any four from: 4\n1 ref. to release from, sarcoplasmic reticulum / SR ;\n2 bind to, troponin / C ;\n3 tropomyosin / B, moves / AW ; A changes shape\n4 binding site / A, exposed / AW ;\n5 myosin head / D, binds to actin\nor\nref. to formation of cross bridge ;\nallow ecf from 1(a)\n\n1(c) no / little, ATP, produced / available ; 2\n(so) no breaking of cross bridges / myosin head not released ;\n© UCLES 2021 Page 5 of 22", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p05.png" ] }, { "id": "9700-2021-mj-43-q02", "question_id": "9700-2021-mj-43-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "2(a)(i) active transport ; 1\n\n2(a)(ii) correct working ; e.g. 2\n945.5\n31 × 30.5 = 945.5 then\n2870\nor\n2870 30.5\n= 92.58 then\n31 92.58\n32.94 / 32.9 / 33 ;\n\n2(a)(iii) thermoregulation 1\nor\nmaintaining (constant), body / core, temperature ; I regulation\n\n2(a)(iv) substrate-linked phosphorylation ; A substrate level phosphorylation 1\n\n2(b) rest (RQ of 0.8) 4\n1 a mix of respiratory substrates\nor\nlipids and, carbohydrates / proteins, are being respired ;\n110 (RQ of 1.0)\n2 respiratory substrate used is carbohydrate / carbohydrate respired (than at rest) ; A named carbohydrate e.g. glucose\n200 (RQ of 1.2)\n3 anaerobic respiration (also) occurring ;\n4 reduced availability of oxygen\nor\nincreased, production / release of CO ;\n2\n© UCLES 2021 Page 6 of 22\n\n2(c) any three from: 3\n1 ref. to oxygen debt ;\noxygen needed to\n2 convert lactate to pyruvate ;\n3 convert lactate to glycogen ;\n4 re-oxygenate, Hb / myoglobin ;\n5 AVP ; e.g. to support a higher metabolic rate / ref. to EPOC\n© UCLES 2021 Page 7 of 22", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p06.png", "../answer-assets/9700_s21_ms_43-p07.png" ] }, { "id": "9700-2021-mj-43-q03", "question_id": "9700-2021-mj-43-q03", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "3(a)(i) any two from: 2\n1 differences in, morphology / phenotype / characteristics ;\n2 differences in, physiology / biochemistry ;\n3 genetic differences / AW ;\n4 differences in behaviour ;\n5 differences in ecological niche ;\n6 isolated, populations / species\nor\nfound in different geographical areas / AW\nor\nreproductively isolated / AW ;\n\n3(a)(ii) any two from: 2\n1 mate them together ;\n2 see if offspring can interbreed / see if offspring are fertile;\n3 ref. to bioinformatics investigation / described ;\n\n3(b) any two from: 2\n1 Fungi ;\n2 Protoctist(a) ;\n3 Prokaryota(e) / Prokaryote ; I bacteria\n© UCLES 2021 Page 8 of 22\n\n3(c) any four from: 4\n1 hard to control / may become invasive / AW ;\n2 may lack predators ;\n3 may lack herbivores ;\n4 may, prey on / parasitise, local / native, species / organisms ;\n5 may compete with, local / native, species / organisms ; A description e.g. eat their food supply\n6 may decrease, biodiversity / species richness / species abundance / AW ;\n7 may have effects on, food web / ecosystem ;\n8 may introduce diseases ;\n\n3(d) any two from: 2\n1 ban on African fruit should be lifted ;\n2 can export more fruit / can export fruit to Asia / find new overseas markets ;\n3 economic benefit / more work / more opportunities for farmers / social benefit ;\n© UCLES 2021 Page 9 of 22", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p08.png", "../answer-assets/9700_s21_ms_43-p09.png" ] }, { "id": "9700-2021-mj-43-q04", "question_id": "9700-2021-mj-43-q04", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 11, "status": "available", "reason": null, "text": "4(a) any five from: 5\n1 gene / DNA, from Bacillus thuringiensis ;\n2 ref. to restriction, enzyme / endonuclease ;\n3 clone gene / amplify gene, using PCR ;\n4 insert, gene / DNA, into plasmid ;\n5 add promoter ;\n6 seal (plasmid) using DNA ligase ;\n7 (maize) tissue / cell / callus / embryo, takes up plasmid / recombinant DNA ;\n8 (maize) expresses new gene / produces Bt toxin ;\n9 AVP ; e.g. Ti (plasmid) / Agrobacterium tumefaciens\n\n4(b)(i) any two from: 2\n1 pollen from Bt maize, kills / is toxic to / harms, caterpillars ;\n2 pollen from non-Bt maize, does not kill / is not toxic to / does not harm, caterpillars ;\n3 (eating) leaves with no pollen does not kill / is not toxic to / does not harm, caterpillars ;\n4 more days of eating pollen from Bt maize gives more caterpillar deaths / AW ;\n© UCLES 2021 Page 10 of 22\n\n4(b)(ii) any four from: 4\n1 Bt pollen did not get deposited (onto milkweed plants) / AW ;\n2 caterpillars and Bt maize located in different areas ;\n3 pollen released at a different time to when caterpillars feed ;\n4 ref. to caterpillars develop resistance (to Bt toxin) ;\n5 ref. to lab and, quantity / toxicity, of Bt pollen ;\n6 AVP ; e.g. in 2019 breeding conditions were better than in 1999 e.g. herbicides may reduce milkweed availability in\nmaize fields\n© UCLES 2021 Page 11 of 22", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p10.png", "../answer-assets/9700_s21_ms_43-p11.png" ] }, { "id": "9700-2021-mj-43-q05", "question_id": "9700-2021-mj-43-q05", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "5(a) any two from: 2\n1 cyclic involves (only) PS1 and non-cyclic involves PS1 and PS2 ;\n2 cyclic produces only ATP and non-cyclic produces ATP and reduced NADP ;\n3 cyclic does not involve photolysis of water and non-cyclic does involve photolysis of water ; A photolysis only occurs\nin non-cyclic\n\n5(b)(i) as a, control / reference tube, for comparison ; R control variable 1\n\n5(b)(ii) tube 2 changes to blue 5\n1 (plant carries out) photosynthesis ;\n2 uses up CO in the, Calvin cycle / light independent stage\n2\nor\nless CO causes pH to increase ; I oxygen\n2\ntube 3 changes to yellow\n3 (snail carries out) respiration ;\n4 produces CO in, the link reaction / Krebs cycle\n2\nor\nmore CO causes pH to decrease ; A more CO acidifies solution I oxygen\n2 2\ntube 4 stays green\n5 both photosynthesis and respiration\nor\nCO produced in respiration is used in photosynthesis\n2\nor\noxygen produced in photosynthesis is used in respiration ;\n© UCLES 2021 Page 12 of 22\n\n9700/43 Cambridge International AS & A Level – Mark Scheme May/June 2021\nPUBLISHED\nQuestion Answer Marks\n5b(iii) any three from: 3\n1 no / less, photosynthesis, so, no / less, CO used ;\n2\n2 detail ; e.g. no light dependent stage / no non-cyclic photophosphorylation\nno / less, Calvin cycle / light independent stage / carbon (dioxide)fixation\n3 respiration occurs producing CO ;\n2\n4 respiration rate slower, in aquatic plants / test-tube 6, than, pond snails / test-tube 7 ;\n5 (so) slight decrease in pH ;\n© UCLES 2021 Page 13 of 22", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p12.png", "../answer-assets/9700_s21_ms_43-p13.png" ] }, { "id": "9700-2021-mj-43-q06", "question_id": "9700-2021-mj-43-q06", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) idea of heat transfer from artery to veins ; 1\n\n6(a)(ii) any one from: 1\nvasodilation / description ; R capillaries / blood vessels move to skin surface\nbehavioural response ; e.g. dive down to cooler waters before surfacing for air\n\n6(b)(i) any four from: 4\n1 concentration of insulin (relatively) constant for all groups before being fed ;\n2 (fasting dolphins) insulin concentration very little change ;\n3 (fed dolphins) insulin concentration increases then decreases ;\n4 (fed dolphins) for 11 g / kg dolphins steep, increase / decrease, in insulin concentration ;\n5 (fed dolphins) for 11 g / kg dolphins high(est) peak in insulin concentration ;\n6 data quote for mp3 or mp4 with time in min ;\n3 kg 21 at 0 min 30 at 180 min 20 at 240 min\n11 kg 10 at 0 min 79 at 90 min 18 at 480 min\n\n6(b)(ii) 79−10 2\n;\n90\n= 0.77 ;\n© UCLES 2021 Page 14 of 22\n\n6(c) any three from: 3\n1 change in a parameter ;\n2 detected by receptor ;\n3 coordination / described ;\n4 (corrective) action taken by effector ;\n5 return to, set point / norm / optimum ;\n© UCLES 2021 Page 15 of 22", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p14.png", "../answer-assets/9700_s21_ms_43-p15.png" ] }, { "id": "9700-2021-mj-43-q07", "question_id": "9700-2021-mj-43-q07", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 haemoglobin less soluble ;\n2 (if oxygen concentration decreases) haemoglobin molecules, stick together / form long fibres ;\n3 red blood cells, pulled out of shape / become sickle shaped ;\n4 blood poor at transporting oxygen ;\n5 (so) less oxygen getting to, cells / tissues / organs ;\n6 red blood cells may, get stuck in / block, capillaries / vessels ;\n7 pain / sickle cell crisis / fatigue ;\n\n7(b)(i) both alleles, contribute to / expressed in, the phenotype (in the heterozygote) ; 1\n\n7(b)(ii) any one from: 1\nsmaller quantity of abnormal haemoglobin ;\nfewer red blood cells become sickled / sickling less severe ; ORA\nnot affected by low(er) oxygen concentration ;\n© UCLES 2021 Page 16 of 22\n\n7(b)(iii) parental SCT SCT 3\nphenotype\nparental HbA HbS HbA HbS ;\ngenotype\ngametes HbA HbS HbA HbS\noffspring HbA HbA HbA HbS (HbA HbS) HbSHbS ;\ngenotypes\noffspring normal SCT (SCT) SCA ;\nphenotypes\nI carrier\n© UCLES 2021 Page 17 of 22", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p16.png", "../answer-assets/9700_s21_ms_43-p17.png" ] }, { "id": "9700-2021-mj-43-q08", "question_id": "9700-2021-mj-43-q08", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "8(a) 1 individuals in a population with, intermediate phenotypes / AW, more likely to, survive / reproduce 3\nor\nindividuals in a population with, intermediate phenotypes / AW, are selected for ;\n2 individuals in a population with extreme phenotypes, die\nor\nindividuals in a population with extreme phenotypes are selected against ;\n3 no change in environment ;\n\n8(b)(i) poor camouflage / AW ; 2\npredation ;\n\n8(b)(ii) narrower curve ; 2\ncurve to right with apex at dark brown ;\n\n8(c) 1 random / chance, change in allele frequency 2\nor\ndescription of alleles not passed onto the next generation ;\n2 larger influence in smaller population / AW ;\n© UCLES 2021 Page 18 of 22", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p18.png" ] }, { "id": "9700-2021-mj-43-q09", "question_id": "9700-2021-mj-43-q09", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 15, "status": "available", "reason": null, "text": "9(a) any six from: 6\n1 add marker gene to the, vector / plasmid ;\n2 gene of interest inserted close to marker gene ;\n3 (marker) gene product / protein, emits light ;\n4 visible colour change ;\n5 ref. to exposing to UV light / laser scanner ;\n6 easy to identify transformed, bacteria / organisms ;\n7 examples ; e.g. GFP\n8 idea of no known risk ;\n9 AVP ; e.g. ref. to gene of interest inserted into marker gene / insertional inactivation\n© UCLES 2021 Page 19 of 22\n\n9(b) any five from: 9\nadvantages\n1 increase in yield ;\n2 improved quality / AW ;\n3 improvement to health / Golden riceTM and vitamin A deficiency ;\n4 longer shelf-life ;\n5 some GM crops are adapted to unfavourable conditions ; A e.g. drought tolerance / nitrogen fixing / salt tolerance\n6 (insect / herbicide, resistant crops) so less money spent on, pesticide / herbicide ;\nany five from:\ndisadvantages\n7 consumer resistance to GM crops ;\n8 may be unsafe for humans / allergies / side effects / harm other animals ;\n9 expensive ;\n10 may have to buy seeds every season ;\n11 seed and related herbicides sales monopolised by big companies ;\n12 ref. to affects organic food ;\n© UCLES 2021 Page 20 of 22", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p19.png", "../answer-assets/9700_s21_ms_43-p20.png" ] }, { "id": "9700-2021-mj-43-q10", "question_id": "9700-2021-mj-43-q10", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 15, "status": "available", "reason": null, "text": "10(a) any seven from: 7\nselective reabsorption – sodium ions\n1 active transport of Na+, out of (pct) cells / into blood ;\n2 Na+ ion concentration, gradient (produced) / reduced in cell ;\n3 Na+ enters (pct) cells from, lumen / tubule / filtrate ;\n4 by facilitated diffusion / using carrier protein ;\n5 cotransport of, glucose / amino acids / ions ;\n6 glucose diffuses into blood ;\nsynapse – calcium ions\n7 (when) presynaptic membrane depolarised ;\n8 calcium (ion) channels / voltage-gated channels, open ;\n9 calcium ions enter presynaptic neurone ;\n10 stimulate vesicles of ACh to, move towards / fuse with, presynaptic membrane ;\n11 causing exocytosis of ACh ;\n© UCLES 2021 Page 21 of 22\n\n10(b) any eight from: 8\ndifferences\nnervous endocrine\n1 communication action potential / impulse and hormone ;\n2 nature of communication electrical (and chemical) and chemical ;\n3 mode of transmission neurone / nerve cell and blood ;\n4 response destination muscle / gland and target, organs / tissue / cells ;\n5 transmission speed fast(er) and slow(er) ;\n6 effects specific / localised and (can be) widespread ;\n7 response speed fast(er) and slow(er) ;\n8 duration short-lived / temporary and can be long-lasting / permanent ;\n9 receptor location on cell surface membrane and either on cell surface membrane or within cell ;\nsimilarities\n10 cell signalling both involve cell signalling ;\n11 detail both involve signal molecule binding to receptor ;\n12 chemicals both involve chemicals ;\n© UCLES 2021 Page 22 of 22", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_43-p21.png", "../answer-assets/9700_s21_ms_43-p22.png" ] }, { "id": "9700-2021-mj-51-q01", "question_id": "9700-2021-mj-51-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 21, "status": "available", "reason": null, "text": "1(a) 0.5 cm3 of the stock solution ; 2\nidea of adding 9.5 cm3 of buffer / water / filling to the 10 cm3 mark with buffer / water (in a volumetric flask) ;\n\n1(b)(i) idea that (result / it, is) quantitative / AW ; ora 1\n\n1(b)(ii) independent variable: 2\nconcentration of ONPG / substrate ;\ndependent variable:\nabsorbance (on colorimeter) ;\n\n1(c)(i) any eight from: 8\n1 ref. to preparing / using at least five concentrations of ONPG\n2 stated range of five dilutions, from 1%v down, with % units\n3 method of keeping β-galactosidase / enzyme, cold (prior to use) ;\n4 idea of bringing enzyme and substrate to temperature / equilibrating, before mixing ;\n5 method of keeping reactants / reaction mixture, at, constant / controlled / stated / standardised, temperature ;\n6 same / constant / stated / standardised / known, volume / concentration / mass of, X / inhibitor ;\n7 same / constant / stated / standardised / known, volume of, ONPG / substrate ;\n8 same / constant / stated / standardised / known, volume / concentration, of β-galactosidase / enzyme ;\n9 ref. to measuring absorbance / intensity of colour (on colorimeter) after one set time ;\n10 additional detail of use of colorimeter ;\n11 repeat at least twice / three replicates, and calculate mean ;\n12 idea of repeating, whole experiment / range of concentrations, without X / inhibitor ;\n13 named hazard and risk and precaution ;\n\n1(c)(ii) 1 curve, to the right of / below, original curve ; 2\n2 curve / line, must meet the plateau of original curve on the graph ;\n\n1(c)(iii) 1 correct placement of V ; 2\nmax\n2 correct placement of K ;\nm\n\n1(c)(iv) (reaction with competitive inhibitor / X) has higher / has increased / increases, K value (compared to no inhibitor) ; 1\nm\n© UCLES 2021 Page 7 of 10\n\n1(d) assume ref. to PPI unless specific treatment stated 3\nany three from:\n1 idea that PPI overall is more effective / is immediately effective, on improvement / removal (of symptoms) ;\n2\neither\nat 12 and 16 weeks / later, overlap of error bars means difference (in effect between PPI and H RA) is not significant ;\n2\nor\nat 4 and 8 weeks / earlier, no overlap of error bars – suggesting difference (in effect, between PPI and H RA) may be,\n2\nsignificant ;\n3 no statistical test to compare groups / t test, done (to test for significance) ;\n4 idea that H RA is catching up / may be better in the long term ;\n2\n5 AVP ; ; any two from:\n• less than 50% patients reported no symptoms\n• no information on severity of symptoms pre-trial\n• no data on side effects\n• size of the two test groups not given\n• no data on long term effects (where H RA may be better)\n2\nQuestion Answer Marks", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_51-p07.png", "../answer-assets/9700_s21_ms_51-p08.png" ] }, { "id": "9700-2021-mj-51-q02", "question_id": "9700-2021-mj-51-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "2(a)(i) idea of compare / AW, observed and expected (data / results / ratios / phenotypes) 1\nor\ndata is categoric / discrete / discontinuous / nominal ;\n\n2(a)(ii) idea of no (significant) difference between the observed and the expected (results) 1\nor\nidea of difference between observed and expected (results) is due to chance ;\n© UCLES 2021 Page 8 of 10\n\n2(a)(iii) 3\n( O−E )2\noffspring phenotype O E\nE\npurple axial flowers 1756 1882 (A 1881) 8.44\n(1881.56250) (8.379175)\npurple, terminal flowers 653 627 1.08\n(627.18750) (1.062338)\nwhite, axial flowers 702 627 8.97\n(627.18750) (8.923823)\nwhite, terminal flowers 234 209 ; 2.99 ;\n(209.06250) (2.974608)\nχ2 = 21.48 ;\n(21.339944)\nχ2= 21.33 / 21.34 / 21.48 for mp3 (to allow for using calculator values or rounded values)\n\n2(a)(iv) 7.82 ; 1\n© UCLES 2021 Page 9 of 10\n\n2(a)(v) apply ecf as needed 3\n1 reject (null hypothesis) and state that, the calculated value / χ2, is higher than, 7.82 / the critical value / the critical value\nthey give in (iv) from the table ;\n2 If null hypothesis rejected:\n(between O and E): there is a significant difference / the difference is not due to chance\nidea that there is a less than 5% probability that the difference is due to chance / there is a more than 95% probability\nthat the difference is not due to chance ;\n3 From mp1 If null hypothesis rejected or mp2 If there is a significant difference / AW stated\nidea that: genes are on the same chromosome / are not on different chromosomes / are linked / show autosomal\nlinkage / do not assort independently ;\nA idea of, ‘may be / can be’, throughout\n© UCLES 2021 Page 10 of 10", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_51-p08.png", "../answer-assets/9700_s21_ms_51-p09.png", "../answer-assets/9700_s21_ms_51-p10.png" ] }, { "id": "9700-2021-mj-52-q01", "question_id": "9700-2021-mj-52-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 18, "status": "available", "reason": null, "text": "1(a) independent variable: 2\nconcentration of, copper (II) sulfate ;\ndependent variable:\nvolume of, oxygen ;\n\n1(b)(i) 1 minimum of five stated dilutions and correct units ; 2\n2 method of serial dilution for a minimum of 2 intermediate (concentrations) ;\n© UCLES 2021 Page 7 of 11\n\n1(b)(ii) any six from: 6\n1 maintaining a constant temperature and a suitable method ;\n2 maintaining a constant pH and use a buffer ;\nmp 3 and 4 and 5: if ‘amount’ rather than ‘volume’, penalise only once and ecf the following ones\n3 same / stated, volume of catalase / enzyme\nor\nsame / stated, concentration of catalase / enzyme ;\n4 same / stated, volume of each copper sulfate / inhibitor solution ;\n5 measure / record, volume of oxygen / gas collected, in set time / set intervals or time taken to reach a set volume ;\n6 state a suitable control ;\n7 use new / fresh (named) solutions for each replicate / experiment ;\n8 repeat at least twice / three replicates, and finding mean for at least one concentration ;\n9 named hazard and risk and precaution ;\ne.g.\nhazard risk precaution\nirritant / allergy\ncatalase / enzyme\nmoderate / medium, hazard\nirritant / allergy\nhydrogen peroxide moderate / medium, hazard\nwear gloves / goggles / mask\nPPA\noxidising agent\ncopper(II) sulfate irritant / allergy\nmoderate / medium, hazard\ncorrosive\ntoxic do not pour down sink\n10 AVP ;\n© UCLES 2021 Page 8 of 11\n\n1(b)(iii) 1 axes correctly orientated with labels ; 3\n2 axes labels have correct units ;\n3 line shows downward trend as concentration of copper(II) sulfate increases ;\ne.g.\nvolume of\noxygen / mm3or cm3\nconcentration of copper sulfate\n/ mol dm–3\n\n1(c)(i) All three lines correctly drawn / indicated ; 3\n1\nV or V correctly labelled for lines drawn ;\nmax max\n2\nK correctly labelled (on correct line) ;\nm\n\n1(c)(ii) plateaus below V / does not reach V / V is lower (than without inhibitor) ; 2\nmax max max\nsame / almost same / similar, K ;\nm\nQuestion Answer Marks", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_52-p07.png", "../answer-assets/9700_s21_ms_52-p08.png", "../answer-assets/9700_s21_ms_52-p09.png" ] }, { "id": "9700-2021-mj-52-q02", "question_id": "9700-2021-mj-52-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 12, "status": "available", "reason": null, "text": "2(a)(i) remove / cover, anthers (from plant B) ; 1\n\n2(a)(ii) method of transferring pollen (from anther) to stigma ; 1\nor\nshake anthers, on / over, stigmas ;\n© UCLES 2021 Page 9 of 11\n\n2(b) any three from: 3\nlight, intensity / duration / amount / strength / wavelength / colour ;\ntemperature ;\nfrequency of watering / amount of water ;\nhumidity ;\nCO / O concentration ;\n2 2\ngrowing medium / soil composition ;\nplanting density ;\n\n2(c)(i) 2\n( O−E )2\noffspring phenotype O E\nE\npurple petals 102 62 25.81\nlong pollen grains\nred petals 112 62 40.32\nround pollen grains\npurple petals 14 62 37.16\nround pollen grains\nred petals 20 62 28.45 ;\nlong pollen grains\nχ2 = 131.74 ;\n© UCLES 2021 Page 10 of 11\n\n2(c)(ii) 1 reject and state that their calculated value / χ2,is higher than 7.82 / critical value ; 3\nany two from:\n2 (if the null hypothesis is rejected) There is a significant difference between the expected and observed values\nor\nthere is a less than 5% / 0.05 probability that the difference has occurred due to chance ;\n3 genes, are on the same chromosome / are not on different chromosomes / are linked / do not assort independently\nor\nautosomal linkage\nor\nalleles (likely to be) inherited together ;\n4 the two genes are close together (on the same chromosome) or small number of recombinants ;\n\n2(d) 1 yes in copper sensitive plants and no in copper tolerant plants / only in copper sensitive plants ; 2\n2 decrease, in percentage / %, viability, in sensitive plants / ora\nor\nslight increase, in percentage / %, viability, in tolerant plants ;\n3 in sensitive plants, there is no overlap of (error) bars, which means the difference may be significant\nor\nin tolerant plants, there is an overlap of (error) bars, which means difference is not significant ;\n4 no statistical test was carried out (in copper-sensitive plants) ;\n5 growth of pollen tube does not indicate pollen grain is viable ;\n6 no reference to concentration of copper ions used in the investigation ;\n© UCLES 2021 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_52-p09.png", "../answer-assets/9700_s21_ms_52-p10.png", "../answer-assets/9700_s21_ms_52-p11.png" ] }, { "id": "9700-2021-mj-53-q01", "question_id": "9700-2021-mj-53-q01", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 21, "status": "available", "reason": null, "text": "1(a) idea of: 2\ngrinding with sand to break open the cells / release enzyme ;\nfiltering through cloth to remove, sand / debris / AW ;\n\n1(b)(i) (idea that result / it, is) quantitative / AW ; 1\n\n1(b)(ii) independent variable: 2\nconcentration of catechol / substrate ;\ndependent variable :\nabsorbance (on colorimeter) ;\n© UCLES 2021 Page 7 of 11\n\n1(c)(i) any eight from: 8\n1 ref. to preparing / using, at least five dilutions concentrations of catechol ;\n2 stated range of at least five concentrations from 1% downwards with % units ;\n3 method of keeping catechol oxidase / enzyme solution / banana extract cold ;\n4 idea of bringing enzyme and substrate to temperature / equilibrating, before mixing ;\n5 method of keeping reactants / reaction mixture, at, constant / controlled / stated / standardised, temperature ;\n6 same / constant / stated / standardised / known, volume / concentration / mass of, Y / inhibitor ;\n7 same / constant / stated / standardised / known, volume of, catechol / substrate ;\n8 same / constant / stated / standardised / known, volume / concentration, of catechol oxidase / enzyme / banana extract ;\n9 ref. to measuring absorbance / intensity of colour (on colorimeter) after one set time ;\n10 additional detail of use of colorimeter ;\n11 repeat at least twice / three replicates, and calculate mean ;\n12 idea of repeating, whole experiment / range of concentrations, without, Y / inhibitor ;\n13 named hazard and risk and precaution ;\n\n1(c)(ii) curve should be to the right of the original curve ; 2\ncurve should plateau below the original curve ;\n\n1(c)(iii) correct placement of V and K ; 2\nmax m\n\n1(c)(iv) (reaction with non-competitive inhibitor) has same K value than with no inhibitor ; 1\nm\n© UCLES 2021 Page 8 of 11\n\n1(d) any three from: 3\n1 combination of drugs gives a larger reduction in blood pressure ;\n2 no error bars ;\n3 no, statistical test / t-test, done to compare groups ;\n4 no data on long term results ;\n5 AVP ; ; any two from:\n• no information on blood pressure prior to trial\n• no information on type of blood pressure\n• no information on number of patients in each group\n• no data on side effects\n• ref. to reduction in blood pressure brought about by the placebo alone\n• no data on, age / gender\n© UCLES 2021 Page 9 of 11", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_53-p07.png", "../answer-assets/9700_s21_ms_53-p08.png", "../answer-assets/9700_s21_ms_53-p09.png" ] }, { "id": "9700-2021-mj-53-q02", "question_id": "9700-2021-mj-53-q02", "subject": "9700", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "2(a)(i) any one from: 1\nidea of compare / AW, observed and expected (data / results / ratios / phenotypes) ;\nor\ndata is, categoric / discrete / discontinuous / nominal ;\n\n2(a)(ii) idea of no (significant) difference between the observed and the expected (results) ; 1\nor\nidea of difference between observed and expected (results) is due to chance ;\n\n2(a)(iii) 3\n( O−E )2\noffspring phenotype O E\nE\nwrinkled wings 44 36 1.78\nrosy eyes (36.000) (1.77778)\nwrinkled wings 2 12 8.33\nred eyes (12.000) (8.33333)\nnormal wings 2 12 8.33\nrosy eyes (12.000) (8.33333)\nnormal wings 16 4 ; 36.00 ;\nred eyes (4.000) (36.00000)\nχ2 = 54.44 ;\n(54.44444)\napply ecf as needed\n\n2(a)(iv) n–1 and probability of 0.05 / one less degree of freedom than number of categories and probability of 0.05 ; 1\n© UCLES 2021 Page 10 of 11\n\n2(a)(v) apply ecf as needed 3\n1 reject (null hypothesis) and state that, the calculated value / χ2, is higher than, 7.82 / the critical value ;\n2 If null hypothesis rejected:\n(between O and E): there is a significant difference / the difference is not due to chance\nidea that there is a less than 5 % probability that the difference is due to chance / there is a more than 95% probability that\nthe difference is not due to chance ;\n3 From mp1 If null hypothesis rejected or mp2 If there is a significant difference / AW, stated\nidea that: genes, are on the same chromosome / are not on different chromosomes / are linked / show autosomal\nlinkage / do not assort independently ;\nA idea of, ‘may be / can be’, throughout mp3\n© UCLES 2021 Page 11 of 11", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-May-June/ms/9700_s21_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-may-june/9700_s21_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s21_ms_53-p10.png", "../answer-assets/9700_s21_ms_53-p11.png" ] }, { "id": "9700-2021-on-41-q01", "question_id": "9700-2021-on-41-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "1(a) 4\ndescription letter\nefferent blood vessel B ;\npart of nephron containing cells that respond to ADH F, G ;\npart of nephron where podocyte cells are located C ;\npart of nephron containing cells that are located in the medulla E, G ;\n\n1(b) any five from: 5\n1 microvilli / basal membrane folds, increase / give large, surface area ;\n2 for / many, (named) transport proteins ;\n3 Na+ / sodium ions, and, glucose / amino acids, move / co-transported, into cell (from filtrate / lumen) ;\n4 Na+ / sodium ions, pumped / move (out of cell) to, blood / tissue fluid ;\n5 ref. to active transport ;\n6 many mitochondria, give / for, energy / ATP ;\n7 tight junctions and reason ;\n\n1(c)(i) any two from: 2\n1 as water potential (of blood) increases concentration of ADH (in the blood) decreases ;\n2 two ADH figures related to two % change in water potential figures ;\n3 between 0% and (+)10% change in water potential, ADH (concentration), does not change / is constant / stays the\nsame / plateaus ;\n© UCLES 2021 Page 5 of 21\n\n1(c)(ii) blood, volume / pressure, decreases ; 1\nQuestion Answer Marks", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p05.png", "../answer-assets/9700_w21_ms_41-p06.png" ] }, { "id": "9700-2021-on-41-q02", "question_id": "9700-2021-on-41-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "2(a)(i) any four from: 4\ndifferences\n1 cotton (enzyme / rubisco activase) has a higher, optimum temperature / temperature at which activity is highest ; ora\n2 maximum / highest / peak, activity higher in flax (enzyme / rubisco activase) (than in cotton) ; ora\n3 cotton (enzyme / rubisco activase) can work at higher temperature (than flax) ;\n4 (at stated temp) <30 °C flax (enzyme) has higher activity than cotton ; ora\n5 (at stated temp) >30 °C cotton (enzyme) has higher activity than flax ; ora\nsimilarities\n6 (activity of) both increases then decreases as temperature increases ;\n7 (enzyme / rubisco activase) activity, same / 0.104 (au), at 30 °C ;\n\n2(a)(ii) any three from: 3\n1 cotton, is adapted to / lives in areas with, high(er) temperatures ; ora\n2 ref. to different, genes / alleles (in cotton vs. flax) ;\n3 ref. to different primary structure of rubisco activase (in cotton vs. flax) ;\n4 ref. to different tertiary structure of rubisco activase (in cotton vs. flax) ;\n5 AVP ;\n© UCLES 2021 Page 6 of 21\n\n2(b) any three from: 3\n1 less / no, CO fixation / carboxylation of RuBP ;\n2\n2 less / no, GP, made into / converted to, TP ;\n3 less / no, regeneration of RuBP ;\n4 less / no, glucose / hexose, made ;\n\n2(c) any two from: 2\n1 take, gene / (c)DNA, for rubisco activase ;\n2 from, cotton and insert into, (false) flax / (named crop) plant / embryo ;\n3 to maintain rubisco action at, high temperatures / >37.5 °C / up to 42.5 °C ;\n4 AVP ;\n© UCLES 2021 Page 7 of 21", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p06.png", "../answer-assets/9700_w21_ms_41-p07.png" ] }, { "id": "9700-2021-on-41-q03", "question_id": "9700-2021-on-41-q03", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 13, "status": "available", "reason": null, "text": "3(a) any four from: 4\n1 use random sampling (technique) ;\n2 repeat and find mean / multiply estimates up for whole area ;\n3 (frame) quadrats to measure, plants / vegetation / stationary organisms ;\n4 detail of using quadrat ;\n5 mark-release-recapture for (named) animals ;\n6 detail of, trapping / marking, (named) animals ;\n7 calculate / use, Simpson’s index (of diversity) ;\n8 species richness and, (relative) abundance / species evenness ;\n9 AVP ;\n© UCLES 2021 Page 8 of 21\n\n3(b) any four from: 4\n1 climate change / end of (last) ice age / (global / local) warming ;\n2 arctic fox, species / population, not well-adapted / unable to adapt ;\n3 hunting, removed / caused extinction of, lynx / large predators ;\n4 introduction of, named / alien / invasive / domestic, species / animal ;\n5 may, eat / compete with / spread disease to, native, species / animal ;\n6 overgrazing problem explained ;\n7 may, change / destroy / disrupt, habitats / food webs ;\n8 AVP ;\n© UCLES 2021 Page 9 of 21\n\n3(c) any five from: 5\n1 obtain, healthy / fertile / wild-caught / captive bred, (founder) animals ;\n2 ref. to genetic, variation / diversity / testing ;\n3 (consider if), sufficient / suitable, habitat / area, available ;\n4 (consider if) sufficient, prey / food, available ;\n5 public safety advice / education ;\n6 (organise) compensation for farmers who lose livestock ;\n7 outlaw, killing / disturbing, lynx ;\n8 (plan to) monitor, lynx / other animal / prey, populations ;\n9 (plan to) cull / control / use contraceptives, if population, grows too much / spreads too far ;\n10 AVP ;\nQuestion Answer Marks", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p08.png", "../answer-assets/9700_w21_ms_41-p09.png", "../answer-assets/9700_w21_ms_41-p10.png" ] }, { "id": "9700-2021-on-41-q04", "question_id": "9700-2021-on-41-q04", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a)(i) 1 crime scene DNA may be present in, small amount / minute quantity ; 2\n2 PCR, amplifies / replicates / copies / multiplies, DNA ;\n\n4(a)(ii) 1 (negative) DNA moves to, positive electrode / anode ; 2\n2 smaller / lighter, fragments move, faster / further / longer distance ;\n© UCLES 2021 Page 10 of 21\n\n4(b)(i) any two from: 2\n1 (GEDmatch) database is large(r than police database) ;\n2 police database only covers people, convicted of / suspected of, crime ;\n3 GEDmatch has data for, innocent people / people with no reason to hide their DNA ;\n4 provides multiple leads to guilty people who are hiding their DNA ;\n\n4(b)(ii) any two from: 2\n1 store of / large quantity of / contains, biological / DNA / genome, data / information ;\n2 for, analysis / processing ;\n3 by, computer / software / algorithm / statistics ;\n\n4(b)(iii) any two from: 2\n1 help police / catch criminals / imprison criminals ;\n2 make, society / community, safe(r) ;\n3 ref. to DNA breakthroughs help, justice / law and order ;\n4 sharing own data also shares relations’ data without their consent ;\n5 AVP ;\n© UCLES 2021 Page 11 of 21", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p10.png", "../answer-assets/9700_w21_ms_41-p11.png" ] }, { "id": "9700-2021-on-41-q05", "question_id": "9700-2021-on-41-q05", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 12, "status": "available", "reason": null, "text": "5(a) embryo ; 1\n\n5(b)(i) any two from: 2\n1 as water potential increases the germination index increases ; ora\n2 water potential in MPa and index figure given for two points ;\n\n5(b)(ii) any three from: 3\n1 low / negative, water potential decreases water, uptake / in, seed ; ora\n2 water, needed / used, to activate embryo / produce gibberellin ;\n3 water, needed / used, for hydrolysis (reactions) ;\n4 starch to maltose / maltose to glucose ;\n5 water, needed / used, as a medium for reactions ;\n6 solutes (lowering water potential) may, be toxic / inhibit enzymes ;\n7 AVP ;\n\n5(c) enzyme 2\namylase / maltase / protease ;\nlocation\naleurone layer ;\n\n5(d)(i) less, energy / resources, to make stem so, more to / larger, flowers or less likely to be damaged by, wind / storm / heavy rain 1\nor takes less, water / fertiliser / time to flower ;\n© UCLES 2021 Page 12 of 21\n\n5(d)(ii) any three from: 3\nshort / dwarf, plants:\n1 are, homozygous recessive / lele ;\n2 le / recessive allele, codes for, non-functional / no, enzyme ;\n3 le / recessive allele / non-functional enzyme, gives inactive gibberellin ;\n4 DELLA proteins, not broken down / stay bound to PIF ;\n5 PIF cannot, bind to promoter / start transcription ;\n6 of gene(s) that promote, growth / cell division / cell elongation ;\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p12.png", "../answer-assets/9700_w21_ms_41-p13.png" ] }, { "id": "9700-2021-on-41-q06", "question_id": "9700-2021-on-41-q06", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "6(a) carbon dioxide ; 1\n\n6(b) any one from: 1\n1 triose phosphate dehydrogenated ;\n2 reduced NAD, made / released ;\n\n6(c)(i) ( glycolysis ) + ( Krebs ) 2\n(ATP + reduced NAD) + (ATP + reduced NAD + reduced FAD)\n(4 – 2) + (4 × 3) + 2 + (6 × 3) + (2 × 2) OR\n2 + 12 + 2 + 18 + 4 ;\n38 ;\n© UCLES 2021 Page 13 of 21\n\n6(c)(ii) any two from: 2\n1 ATP / energy, used to transport, pyruvate / reduced NAD / products of glycolysis, into (named part of) mitochondria ;\n2 some protons leak from intermembrane space ;\n3 some energy lost as heat ;\n4 glucose may not be completely broken down / some intermediates are used in different metabolic processes ;\n5 reduced NAD may be used for other (metabolic) reactions ;\n\n6(d) any three from: 3\n1 coenzymes ;\n2 help / for, dehydrogenases / dehydrogenation (reactions) ;\n3 ref. to glycolysis / link reaction / Krebs cycle ;\n4 carry / transfer / transport / bring, hydrogens / H ;\n5 to, ETC / inner mitochondrial membrane / crista(e) ;\n© UCLES 2021 Page 14 of 21\n\n6(e) any three from: 3\n1 less / no, energy (release from electron transfer / ETC) ;\n2 less / no, chemiosmosis ;\n3 fewer / no, protons, move / pumped, to intermembrane space ;\n4 less (steep) / no, proton gradient ;\n5 fewer / no, protons, move / diffuse, through ATP synth(et)ase ;\n6 less / no, ATP synthesised ;\nQuestion Answer Marks", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p13.png", "../answer-assets/9700_w21_ms_41-p14.png", "../answer-assets/9700_w21_ms_41-p15.png" ] }, { "id": "9700-2021-on-41-q07", "question_id": "9700-2021-on-41-q07", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 base / nucleotide, insertion / deletion / substitution ;\n2 frameshift / changed reading frame ;\n3 ref. to stop codon ;\n4 changes / different, primary structure / amino acid sequence ;\n5 changes / different, folding / 3D shape / 3o structure, of enzyme / protein ;\n6 active site does not, bind / fit, substrate / complex molecules ;\n© UCLES 2021 Page 15 of 21\n\n7(b) 1 key e.g. H = normal (allele) h = Hunter (syndrome allele) ; 5\nparental normal male normal female\nphenotype\n2 parental XHY XH Xh ;\ngenotype\ngametes ( XH Y XH Xh )\n3 offspring XH XH XH Xh XH Y Xh Y ;\ngenotypes\n4 offspring normal normal / carrier normal Hunter S ;\nphenotypes female female male male\n5 probability 0.25 / 25% / 1 in 4 ;\n© UCLES 2021 Page 16 of 21", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p15.png", "../answer-assets/9700_w21_ms_41-p16.png" ] }, { "id": "9700-2021-on-41-q08", "question_id": "9700-2021-on-41-q08", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 5, "status": "available", "reason": null, "text": "8 any five from: 5\n1 due to (Great Central) Valley / during migration, populations / they, are separated / geographically isolated ;\n2 no, mating / breeding / gene flow, between, them / populations ;\n3 different (named), selection pressures / environments / conditions / habitats ;\n4 different mutations ;\n5 natural selection ;\n6 genetic drift / founder effect ;\n7 change in allele frequency OR change in / different, gene pool ;\n8 leads to different, morphological / behavioural / biochemical / physiological, features ;\n9 allopatric speciation ;\n© UCLES 2021 Page 17 of 21", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p17.png" ] }, { "id": "9700-2021-on-41-q09", "question_id": "9700-2021-on-41-q09", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 15, "status": "available", "reason": null, "text": "9(a) any seven from 7\n1 (H+) carrier / pump (protein), in cell surface membrane (of guard cell) ;\n2 hydrogen ions / protons / H ions / H+, leave / exit (cell) ;\n3 using, energy / ATP ;\n4 low H+ (in cell) / more negative charge (than outside) ;\n5 K+ channel (proteins) open ;\n6 K+, move into / enter, cell (by facilitated diffusion) ;\n7 Cl – ions, move into / enter (cell) ;\n8 water / solute, potential of cell decreases ;\n9 water moves in (to cell) by osmosis ;\n10 cell / vacuole, volume increases ;\n11 (cells) are / become, turgid ;\n12 thick inner cell wall (of guard cell) ;\n13 AVP ;\n© UCLES 2021 Page 18 of 21\n\n9(b) any eight from: 8\n1 C4, plants / pathway ;\n2 stop / decrease, photorespiration ;\n3 mesophyll cells form (tightly packed) ring ;\n4 around / surrounding, bundle sheath (cells) ;\n5 (initial) CO carbon, fixation in mesophyll and Calvin cycle in bundle sheath ;\n2 /\n6 RuBP / rubisco, in bundle sheath (cells) ;\n7 oxygen / air, cannot reach, RuBP / rubisco / bundle sheath ;\n8 CO combines with, PEP / PEP carboxylase (in mesophyll) ;\n2\n9 to form, oxaloacetate / malate ;\n10 (malate) releases carbon dioxide in bundle sheath (cells) ;\n11 RuBP, carboxylated / reacts with carbon dioxide ;\n12 PEP carboxylase has high optimum temperature / tolerates high temperatures ;\n© UCLES 2021 Page 19 of 21", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p18.png", "../answer-assets/9700_w21_ms_41-p19.png" ] }, { "id": "9700-2021-on-41-q10", "question_id": "9700-2021-on-41-q10", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 15, "status": "available", "reason": null, "text": "10(a) any nine from: 9\n1 Na+ / sodium ion, channels open ;\n2 Na+ / sodium ions, enter, neurone / axon / (nerve) cell ;\n3 membrane (potential) becomes, positive / +40 mV / depolarised ;\n4 (repolarisation / after peak) Na+ / sodium ion, channels close ;\n5 K+ / potassium ion, channels open ;\n6 K+ / potassium ions, leave / move out (of cell) ;\n7 membrane (potential) becomes, negative / –90 mV / repolarised ;\n8 local circuits ;\n9 myelin sheath / Schwann cells, insulates / stops ion movement ;\n10 action potential / depolarisation, only occurs at nodes of Ranvier ;\n11 saltatory conduction ;\n12 fast transmission (of, action potential / impulse) ;\n13 one-way transmission (of, action potential / impulse) ;\n14 AVP ;\n© UCLES 2021 Page 20 of 21\n\n10(b) any six from: 6\n1 maintain / keep / regulate, internal, environment / conditions ;\n2 within, narrow / set, limits or around, optimum value / set point / norm ;\n3 low (body) temperature and consequence ;\n4 high (body) temperature and consequence ;\n5 low blood glucose (concentration) and consequence ;\n6 high blood glucose concentration and consequence ;\n7 low, (blood) water potential / ψ, and consequence ;\n8 high, (blood) water potential / ψ, and consequence ;\n© UCLES 2021 Page 21 of 21", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_41-p20.png", "../answer-assets/9700_w21_ms_41-p21.png" ] }, { "id": "9700-2021-on-42-q01", "question_id": "9700-2021-on-42-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "1(a) 4\nfeature letter\nglomerular filtrate E ;\nbasement membrane C ;\npodocyte cells D ;\ncapillary endothelial cell A ;\n\n1(b) any five from: 5\n1 afferent arteriole, (lumen) wider / has larger diameter, than efferent ;\n2 causes high, blood / hydrostatic, pressure in, glomerulus / capillaries ;\n3 pores / gaps / fenestrations, in capillary endothelium ; I holes in cells\n4 basement membrane acts as a filter / AW ;\n5 detail of podocytes ; e.g. finger-like structures / folds / slit pores\n6 correct ref. to passage of substances ; e.g. basement membrane stops, blood cells / large proteins / molecules above\nRMM 68 000–70 000 or allows urea / glucose / amino acids / ions / water\n7 idea of network of capillaries ;\n\n1(c)(i) any two from: 2\n1 as (mean arterial blood) pressure increases the GFR increases, levels off and increases / AW ;\n2 (plateau occurs) at 100 cm3 min–1 / between 10 and 20 kPa ;\n3 AVP ; e.g. plateau is normal or healthy value\n© UCLES 2021 Page 5 of 24\n\n1(c)(ii) any one from: 1\n1 kidney, damage / disease / cancer ;\n2 dehydration ;\n3 low, blood / hydrostatic, pressure or blood loss ;\n4 AVP ; e.g. other (relevant) disease\nQuestion Answer Marks", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p05.png", "../answer-assets/9700_w21_ms_42-p06.png" ] }, { "id": "9700-2021-on-42-q02", "question_id": "9700-2021-on-42-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "2(a) any one from: 1\n1 industrialisation ;\n2 transportation ;\n3 power stations ;\n4 burning of fuels ;\n© UCLES 2021 Page 6 of 24\n\n2(b) any three from: 3\n1 genetically modified has a higher (dry) mass throughout the experiment ; ora\n2 genetically modified has a (slightly) higher rate of / steeper, increase (in dry mass) ; ora\n3 the largest difference in (dry) mass is after day 8 ;\n4 paired data quote with units ;\ntime / days dry mass / g dm–3\ngenetically modified unmodified difference between the two\n± 0.02 ± 0.02 ± 0.04\n2 0.22 0.13 0.09\n4 0.48 0.34 0.14\n6 0.62 0.48 0.14\n8 0.88 0.74 0.14\n10 1.24 0.96 0.28\n12 1.54 1.31 0.23\n14 1.86 1.52 0.34\nrate of growth over 14 days\ngenetically modified = 1.86 / 14 = 0.13 g dm–3 day–1\nunmodified = 1.52 / 14 = 0.11 g dm–3 day–1\n© UCLES 2021 Page 7 of 24\n\n2(c) any three from: 3\n1 (more rubisco so) greater rate of / more, carbon (dioxide) fixation ; AW\n2 (so) greater rate of / more, GP produced ;\n3 so greater rate of / more TP, produced (from GP) ;\n4 (so) greater rate of / more, regeneration of RuBP ;\n5 (so) greater rate of / more, Calvin cycle ;\n6 AVP ; e.g. carbon fixation is a rate-limiting step / concentration of rubisco is a limiting factor\n\n2(d) any three from: 3\n1 glucose for respiration ;\n2 starch for storage ;\n3 cellulose to make cells walls ;\n4 sucrose for, translocation / described ;\n5 fatty acids and glycerol / lipid, to make membranes\nor\nfatty acids and glycerol / lipid / fats, for storage\nor\nfatty acids to make acetyl CoA (for Krebs cycle) ;\n6 amino acids to make, proteins / enzymes ;\n7 proteins for, growth / repair ;\n© UCLES 2021 Page 8 of 24\n\n2(e) any one from: 1\n1 idea of fast(er) growth rate / reproduction ;\n2 quicker to set up / AW ;\n3 cheaper to set up / AW ;\n4 (as aquatic) not using (useful) land ;\n5 can, culture / grow, algae in the lab ;\nQuestion Answer Marks", "source_pages": [ 6, 7, 8, 9 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p06.png", "../answer-assets/9700_w21_ms_42-p07.png", "../answer-assets/9700_w21_ms_42-p08.png", "../answer-assets/9700_w21_ms_42-p09.png" ] }, { "id": "9700-2021-on-42-q03", "question_id": "9700-2021-on-42-q03", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 12, "status": "available", "reason": null, "text": "3(a) any three from: 3\n1 seed / embryo, absorbs water ;\n2 (stimulates) embryo to produce gibberellin ;\n3 gibberellin moves to aleurone layer ;\n4 gene coding for amylase, expressed / transcribed ;\n5 translation of mRNA (to produce amylase) ;\n6 AVP ; e.g. gibberellin binds to receptor / ref. destruction of DELLA protein\n\n3(b)(i) endosperm ; 1\n© UCLES 2021 Page 9 of 24\n\n3(b)(ii) any four from: 4\n1 amylase activity increases ;\n2 as (seeds) produce more amylase ;\n3 percentage of starch decreases ;\n4 amylase, hydrolyses / breaks down, starch ;\n5 idea of a change at an increasing rate (for either) ; A exponential change\n6 data quote: amylase or starch at two different days ;\ntime / days amylase activity / au percentage of starch remaining\n0 0.0 100\n1 0.2 99\n2 0.8 98\n3 2.4 95\n4 5.0 91\n5 8.4 82\naccept manipulated data\n© UCLES 2021 Page 10 of 24\n\n3(c)(i) any three from: 3\n1 enzyme, denatured / deactivated / inactivated ;\n2 changes, tertiary structure / 3D shape, of amylase ; A enzyme\n3 changes shape of active site ;\n4 active site, no longer complementary / does not bind, to starch / substrate\nor\nno, ESC / enzyme-substrate complexes, formed ;\n5 AVP ; e.g. removes water from embryo for gibberellin synthesis / removes water from endosperm for hydrolytic\nreactions\n\n3(c)(ii) any one from: 1\n1 stops, sugars / glucose, from being used ; ora\n2 ensures (enough) sugars for beer production ;\n© UCLES 2021 Page 11 of 24", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p09.png", "../answer-assets/9700_w21_ms_42-p10.png", "../answer-assets/9700_w21_ms_42-p11.png" ] }, { "id": "9700-2021-on-42-q04", "question_id": "9700-2021-on-42-q04", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "4(a)(i) any four from: 4\n1 obtain single-stranded DNA ;\n2 label DNA with fluorescent, dye / tag / label ;\n3 probes on, chip / microarray ;\n4 each probe is unique to a particular, SNP / gene / allele ;\n5 DNA (added), binds / hybridises, to probes ;\n6 wash off excess DNA (after hybridisation) ;\n7 (view under) UV light / laser scanner / high resolution digital camera ;\n8 fluorescence indicates presence of, SNP / gene ; R gene expressed\n\n4(a)(ii) any two from: 2\n1 large database ;\n2 use database to find, SNPs / probes ;\n3 fast / accurate / efficient ;\n4 ref. to (computer) software / algorithms ;\n5 ref. to statistics / statistical analysis ;\n6 idea of, 17 000 × 500 000 / 8.5 × 109, data points ;\n\n4(b)(i) 1 and 6 ; 1\n© UCLES 2021 Page 12 of 24\n\n4(b)(ii) any two from: 2\n1 all diseases, are autosomal / not associated with X chromosome / not sex-linked ;\n2 all diseases are associated with SNP on chromosome 6 ;\n3 type 1 and type 2 diabetes SNPs are associated with chromosomes 12 and 16 (but not rheumatoid arthritis) ;\n4 type 2 diabetes SNP associated with chromosome 10 (but not type 1 diabetes and rheumatoid arthritis) ;\n5 arthritis and type 1 diabetes have higher level of association (with each other) than with type 2 diabetes ;\n6 rheumatoid arthritis has fewest number of SNPs\nor\ntype 1 and type 2 diabetes has more SNPs (than rheumatoid arthritis) ;\n© UCLES 2021 Page 13 of 24\n\n4(c) any three from: 3\n1 DNA analysis not available for everyone ;\n2 lifestyle change ; A e.g. lose weight / stop smoking / take exercise\n3 early treatment ;\n4 allows people to plan ; e.g. organise care / appoint power of attorney / take out medical insurance / make will / gift\nproperty to children / retire early\n5 decide whether to have children / ref. (therapeutic) termination ;\n6 results may cause, anxiety / stress / panic / depression (if positive)\nor\nreduce worry (if negative) ;\n7 results may affect ability to get, insurance / credit / jobs ;\n8 idea of predictions may not be accurate ;\nQuestion Answer Marks", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p12.png", "../answer-assets/9700_w21_ms_42-p13.png", "../answer-assets/9700_w21_ms_42-p14.png" ] }, { "id": "9700-2021-on-42-q05", "question_id": "9700-2021-on-42-q05", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "5(a) Fig. 5.1: species ; 3\nFig. 5.2: genetic ;\nFig. 5.3: habitat / ecosystem ;\n© UCLES 2021 Page 14 of 24\n\n5(b)(i) plants: 4\n1 quadrats ;\n2 transects ;\n3 ref. to use, ACFOR / Braun-Blanquet\nor\nestimate percentage cover (of species)\ncount species\ncalculate plus species abundance\nrecord species density\nAW species frequency ;\ninsects:\n4 pooters / pitfall traps / nets / light traps / sugar traps ;\n5 mark-release-recapture ;\naccept in either section:\n6 (identification) keys ;\n\n5(b)(ii) estimate biodiversity: Simpson’s index (of biodiversity) ; 2\ntest relationship: Pearson’s linear correlation coefficient / Spearman’s rank correlation ;\n© UCLES 2021 Page 15 of 24\n\n5(c) any three from: 3\nnegative\n1 smaller crop area so lower yield ;\n2 prairie strip insects may feed on crop ;\n3 (so) less, profit / income ; must be linked to mp1 or mp2\npositive\n4 (soil) more fertile / described, so higher yield ;\n5 less / no, fertiliser / phosphorus compounds / nitrogen compounds, used ; ignore minerals\n6 (so) more, profit / income\nor\nreduction in expenses ; must be linked to mp4 or mp5\n© UCLES 2021 Page 16 of 24", "source_pages": [ 14, 15, 16 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p14.png", "../answer-assets/9700_w21_ms_42-p15.png", "../answer-assets/9700_w21_ms_42-p16.png" ] }, { "id": "9700-2021-on-42-q06", "question_id": "9700-2021-on-42-q06", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "6(a)(i) any four from: 4\n1 water soluble ;\n2 (so) easily transported around the cell ;\n3 (ATP) loses, P / phosphate group ;\ni\n4 hydrolysed by ATPase / (ATP is) stable molecule ;\n5 to release energy, immediately / in small packets\nor\nref. to 30.5 kJ (mol–1) ;\n6 can be, recycled / regenerated\nor\nATP ⇄ ADP + P ;\ni\n\n6(a)(ii) any two from: 2\n1 unwinding DNA ;\n2 activating (RNA) nucleotides ;\n3 ref. to mRNA synthesis ;\n4 peptide bond formation / joining amino acids ;\n5 AVP ; e.g. post translation modification / amino acid activation / moving ribosomes along mRNA / movement of mRNA\nfrom nucleus\n© UCLES 2021 Page 17 of 24\n\n6(b)(i) 2\nstatement letter\nthe site of the Krebs Cycle A\na phospholipid bilayer impermeable to H+ ions E / D\nthe site of translation C\n;;\nall correct = 2 marks\n1 or 2 correct = 1 mark\n6b(ii) (2 × π × 0.362 ) + (2 × π × 0.36 × 5.25) 2\nor\n2π × 0.36 (0.36 + 5.25) ;\n12.7\nor\n12.68\nor\n12.69 ;\naccept 3.14 or π in workings\n\n6(b)(iii) 1 (more cristae results in) more, ETC / (named) carrier proteins / ATP synthase ; 2\nor\n(more cristae results in) more, oxidative phosphorylation / chemiosmosis / ATP synthesis ;\n2 (because) cardiac muscle must undergo continuous contractions / AW ;\n© UCLES 2021 Page 18 of 24", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p17.png", "../answer-assets/9700_w21_ms_42-p18.png" ] }, { "id": "9700-2021-on-42-q07", "question_id": "9700-2021-on-42-q07", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) any two from: 2\n1 tyrosine converted to, DOPA / dopaquinone ;\n2 dopaquinone converted to melanin ;\n3 ref. to melanocytes ;\n\n7(b)(i) parental (black x yellow) 6\nphenotype\nparental BbEe x Bbee ;\ngenotype\ngametes BE Be bE be Be be ;\noffspring\ngenotypes ;; BBEe BbEe BbEe BBee Bbee Bbee bbee bbEe\noffspring\nphenotypes ; black black black yellow yellow yellow yellow brown\nratio 3 black : 1 brown : 4 yellow ;\necf to max 3\n\n7(b)(ii) transcription factor ; 1\n© UCLES 2021 Page 19 of 24", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p19.png" ] }, { "id": "9700-2021-on-42-q08", "question_id": "9700-2021-on-42-q08", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 5, "status": "available", "reason": null, "text": "8 any five from: 5\n1 geographical, isolation / separation\nor\nref. to Panama / land, separating populations ;\n2 no, gene flow / interbreeding, between both populations ;\n3 different, environmental conditions / selection pressures ;\n4 random / different, mutations ;\n5 (different), alleles selected for / gene pool / changes in allele frequency ;\n6 over time populations have different, morphological / physiological / behavioural, features ;\n7 eventually reproductive isolation occurs ;\n8 allopatric speciation ;\n© UCLES 2021 Page 20 of 24", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p20.png" ] }, { "id": "9700-2021-on-42-q09", "question_id": "9700-2021-on-42-q09", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 15, "status": "available", "reason": null, "text": "9(a) any nine from: 9\n1 hypothalamus / osmoreceptors, detects changes in water potential of blood ;\n2 (causes) posterior pituitary gland ;\n3 (to) release ADH into blood ;\n4 ADH binds to receptors ;\n5 on cell surface membrane of collecting duct (cells) ;\n6 stimulates enzyme cascade / phosphorylase enzyme produced ;\n7 vesicles, move towards / fuse with, cell surface membrane ;\n8 (vesicles have) aquaporins ;\n9 collecting duct, membranes / cells / walls, more permeable to water ;\n10 water moves, down water potential gradient / by osmosis ;\n11 into, (collecting duct) cells / tissue fluid / blood ;\n12 water potential (of blood) returns to set point ;\n© UCLES 2021 Page 21 of 24\n\n9(b) any six from: 6\n1 dendrites attached to cell body ;\n2 nucleus in, cell body / soma ;\n3 many mitochondria ;\n4 much rough endoplasmic reticulum / Nissl’s granules (in cell body) ;\n5 long axon ;\n6 synaptic knobs / synaptic bulbs / terminal branches / axon terminals ;\n7 Schwann cells / myelin sheath / myelinated ;\n8 nodes of Ranvier ;\n9 cell body in, CNS / brain and spinal cord ;\naccept from labelled diagram\nif sensory neurone described – max 5\n© UCLES 2021 Page 22 of 24", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p21.png", "../answer-assets/9700_w21_ms_42-p22.png" ] }, { "id": "9700-2021-on-42-q10", "question_id": "9700-2021-on-42-q10", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 15, "status": "available", "reason": null, "text": "10(a) any seven from: 7\n1 (dip stick) has immobilised enzymes ;\n2 (dip stick) dipped in urine ; A person, urinates / AW, on stick\n3 glucose oxidase and peroxidase ;\n4 glucose reacts to give hydrogen peroxide ;\n5 (hydrogen peroxide reacts with) colourless substance / chromogen ;\n6 to give, colour change / coloured substance ;\n7 compare with colour chart ;\n8 more glucose gives darker colour / colour intensity gives glucose quantity ;\n9 AVP ; e.g. doesn’t give current blood glucose concentration / not numerical / semi-quantitative\n© UCLES 2021 Page 23 of 24\n\n10(b) any eight from: 8\n1 dominant allele / Le, codes for, functional enzyme ; ora\n2 (enzyme) produces active gibberellin (GA) ;\n3 DELLA (protein) inhibits, transcription factor / PIF\nor\nDELLA (protein) prevents transcription ;\n4 gibberellin / GA, binds to receptor (complex) ; ignore cell surface membrane\n5 ref. to enzyme involved ;\n6 causes DELLA (protein) destruction ; R GA breaks DELLA (protein)\n7 transcription factor / PIF / RNA polymerase, binds to, DNA / promoter ;\n8 (growth) genes, switched on / expressed / transcribed\nor\ntranscription occurs ;\n9 cell walls loosen / acid growth (described) ;\n10 (so) cells can expand when water enters ;\n11 ref. to cell, elongation / division ;\n12 increases internode length ;\n13 AVP ; e.g. ref. to expansins / interaction with auxin / ref. to XET\n© UCLES 2021 Page 24 of 24", "source_pages": [ 23, 24 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_42-p23.png", "../answer-assets/9700_w21_ms_42-p24.png" ] }, { "id": "9700-2021-on-43-q01", "question_id": "9700-2021-on-43-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "1(a) 4\ndescription letter\nefferent blood vessel B ;\npart of nephron containing cells that respond to ADH F, G ;\npart of nephron where podocyte cells are located C ;\npart of nephron containing cells that are located in the medulla E, G ;\n\n1(b) any five from: 5\n1 microvilli / basal membrane folds, increase / give large, surface area ;\n2 for / many, (named) transport proteins ;\n3 Na+ / sodium ions, and, glucose / amino acids, move / co-transported, into cell (from filtrate / lumen) ;\n4 Na+ / sodium ions, pumped / move (out of cell) to, blood / tissue fluid ;\n5 ref. to active transport ;\n6 many mitochondria, give / for, energy / ATP ;\n7 tight junctions and reason ;\n\n1(c)(i) any two from: 2\n1 as water potential (of blood) increases concentration of ADH (in the blood) decreases ;\n2 two ADH figures related to two % change in water potential figures ;\n3 between 0% and (+)10% change in water potential, ADH (concentration), does not change / is constant / stays the\nsame / plateaus ;\n© UCLES 2021 Page 5 of 21\n\n1(c)(ii) blood, volume / pressure, decreases ; 1\nQuestion Answer Marks", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p05.png", "../answer-assets/9700_w21_ms_43-p06.png" ] }, { "id": "9700-2021-on-43-q02", "question_id": "9700-2021-on-43-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "2(a)(i) any four from: 4\ndifferences\n1 cotton (enzyme / rubisco activase) has a higher, optimum temperature / temperature at which activity is highest ; ora\n2 maximum / highest / peak, activity higher in flax (enzyme / rubisco activase) (than in cotton) ; ora\n3 cotton (enzyme / rubisco activase) can work at higher temperature (than flax) ;\n4 (at stated temp) <30 °C flax (enzyme) has higher activity than cotton ; ora\n5 (at stated temp) >30 °C cotton (enzyme) has higher activity than flax ; ora\nsimilarities\n6 (activity of) both increases then decreases as temperature increases ;\n7 (enzyme / rubisco activase) activity, same / 0.104 (au), at 30 °C ;\n\n2(a)(ii) any three from: 3\n1 cotton, is adapted to / lives in areas with, high(er) temperatures ; ora\n2 ref. to different, genes / alleles (in cotton vs. flax) ;\n3 ref. to different primary structure of rubisco activase (in cotton vs. flax) ;\n4 ref. to different tertiary structure of rubisco activase (in cotton vs. flax) ;\n5 AVP ;\n© UCLES 2021 Page 6 of 21\n\n2(b) any three from: 3\n1 less / no, CO fixation / carboxylation of RuBP ;\n2\n2 less / no, GP, made into / converted to, TP ;\n3 less / no, regeneration of RuBP ;\n4 less / no, glucose / hexose, made ;\n\n2(c) any two from: 2\n1 take, gene / (c)DNA, for rubisco activase ;\n2 from, cotton and insert into, (false) flax / (named crop) plant / embryo ;\n3 to maintain rubisco action at, high temperatures / >37.5 °C / up to 42.5 °C ;\n4 AVP ;\n© UCLES 2021 Page 7 of 21", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p06.png", "../answer-assets/9700_w21_ms_43-p07.png" ] }, { "id": "9700-2021-on-43-q03", "question_id": "9700-2021-on-43-q03", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 13, "status": "available", "reason": null, "text": "3(a) any four from: 4\n1 use random sampling (technique) ;\n2 repeat and find mean / multiply estimates up for whole area ;\n3 (frame) quadrats to measure, plants / vegetation / stationary organisms ;\n4 detail of using quadrat ;\n5 mark-release-recapture for (named) animals ;\n6 detail of, trapping / marking, (named) animals ;\n7 calculate / use, Simpson’s index (of diversity) ;\n8 species richness and, (relative) abundance / species evenness ;\n9 AVP ;\n© UCLES 2021 Page 8 of 21\n\n3(b) any four from: 4\n1 climate change / end of (last) ice age / (global / local) warming ;\n2 arctic fox, species / population, not well-adapted / unable to adapt ;\n3 hunting, removed / caused extinction of, lynx / large predators ;\n4 introduction of, named / alien / invasive / domestic, species / animal ;\n5 may, eat / compete with / spread disease to, native, species / animal ;\n6 overgrazing problem explained ;\n7 may, change / destroy / disrupt, habitats / food webs ;\n8 AVP ;\n© UCLES 2021 Page 9 of 21\n\n3(c) any five from: 5\n1 obtain, healthy / fertile / wild-caught / captive bred, (founder) animals ;\n2 ref. to genetic, variation / diversity / testing ;\n3 (consider if), sufficient / suitable, habitat / area, available ;\n4 (consider if) sufficient, prey / food, available ;\n5 public safety advice / education ;\n6 (organise) compensation for farmers who lose livestock ;\n7 outlaw, killing / disturbing, lynx ;\n8 (plan to) monitor, lynx / other animal / prey, populations ;\n9 (plan to) cull / control / use contraceptives, if population, grows too much / spreads too far ;\n10 AVP ;\nQuestion Answer Marks", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p08.png", "../answer-assets/9700_w21_ms_43-p09.png", "../answer-assets/9700_w21_ms_43-p10.png" ] }, { "id": "9700-2021-on-43-q04", "question_id": "9700-2021-on-43-q04", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a)(i) 1 crime scene DNA may be present in, small amount / minute quantity ; 2\n2 PCR, amplifies / replicates / copies / multiplies, DNA ;\n\n4(a)(ii) 1 (negative) DNA moves to, positive electrode / anode ; 2\n2 smaller / lighter, fragments move, faster / further / longer distance ;\n© UCLES 2021 Page 10 of 21\n\n4(b)(i) any two from: 2\n1 (GEDmatch) database is large(r than police database) ;\n2 police database only covers people, convicted of / suspected of, crime ;\n3 GEDmatch has data for, innocent people / people with no reason to hide their DNA ;\n4 provides multiple leads to guilty people who are hiding their DNA ;\n\n4(b)(ii) any two from: 2\n1 store of / large quantity of / contains, biological / DNA / genome, data / information ;\n2 for, analysis / processing ;\n3 by, computer / software / algorithm / statistics ;\n\n4(b)(iii) any two from: 2\n1 help police / catch criminals / imprison criminals ;\n2 make, society / community, safe(r) ;\n3 ref. to DNA breakthroughs help, justice / law and order ;\n4 sharing own data also shares relations’ data without their consent ;\n5 AVP ;\n© UCLES 2021 Page 11 of 21", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p10.png", "../answer-assets/9700_w21_ms_43-p11.png" ] }, { "id": "9700-2021-on-43-q05", "question_id": "9700-2021-on-43-q05", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 12, "status": "available", "reason": null, "text": "5(a) embryo ; 1\n\n5(b)(i) any two from: 2\n1 as water potential increases the germination index increases ; ora\n2 water potential in MPa and index figure given for two points ;\n\n5(b)(ii) any three from: 3\n1 low / negative, water potential decreases water, uptake / in, seed ; ora\n2 water, needed / used, to activate embryo / produce gibberellin ;\n3 water, needed / used, for hydrolysis (reactions) ;\n4 starch to maltose / maltose to glucose ;\n5 water, needed / used, as a medium for reactions ;\n6 solutes (lowering water potential) may, be toxic / inhibit enzymes ;\n7 AVP ;\n\n5(c) enzyme 2\namylase / maltase / protease ;\nlocation\naleurone layer ;\n\n5(d)(i) less, energy / resources, to make stem so, more to / larger, flowers or less likely to be damaged by, wind / storm / heavy rain 1\nor takes less, water / fertiliser / time to flower ;\n© UCLES 2021 Page 12 of 21\n\n5(d)(ii) any three from: 3\nshort / dwarf, plants:\n1 are, homozygous recessive / lele ;\n2 le / recessive allele, codes for, non-functional / no, enzyme ;\n3 le / recessive allele / non-functional enzyme, gives inactive gibberellin ;\n4 DELLA proteins, not broken down / stay bound to PIF ;\n5 PIF cannot, bind to promoter / start transcription ;\n6 of gene(s) that promote, growth / cell division / cell elongation ;\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p12.png", "../answer-assets/9700_w21_ms_43-p13.png" ] }, { "id": "9700-2021-on-43-q06", "question_id": "9700-2021-on-43-q06", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "6(a) carbon dioxide ; 1\n\n6(b) any one from: 1\n1 triose phosphate dehydrogenated ;\n2 reduced NAD, made / released ;\n\n6(c)(i) ( glycolysis ) + ( Krebs ) 2\n(ATP + reduced NAD) + (ATP + reduced NAD + reduced FAD)\n(4 – 2) + (4 × 3) + 2 + (6 × 3) + (2 × 2) OR\n2 + 12 + 2 + 18 + 4 ;\n38 ;\n© UCLES 2021 Page 13 of 21\n\n6(c)(ii) any two from: 2\n1 ATP / energy, used to transport, pyruvate / reduced NAD / products of glycolysis, into (named part of) mitochondria ;\n2 some protons leak from intermembrane space ;\n3 some energy lost as heat ;\n4 glucose may not be completely broken down / some intermediates are used in different metabolic processes ;\n5 reduced NAD may be used for other (metabolic) reactions ;\n\n6(d) any three from: 3\n1 coenzymes ;\n2 help / for, dehydrogenases / dehydrogenation (reactions) ;\n3 ref. to glycolysis / link reaction / Krebs cycle ;\n4 carry / transfer / transport / bring, hydrogens / H ;\n5 to, ETC / inner mitochondrial membrane / crista(e) ;\n© UCLES 2021 Page 14 of 21\n\n6(e) any three from: 3\n1 less / no, energy (release from electron transfer / ETC) ;\n2 less / no, chemiosmosis ;\n3 fewer / no, protons, move / pumped, to intermembrane space ;\n4 less (steep) / no, proton gradient ;\n5 fewer / no, protons, move / diffuse, through ATP synth(et)ase ;\n6 less / no, ATP synthesised ;\nQuestion Answer Marks", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p13.png", "../answer-assets/9700_w21_ms_43-p14.png", "../answer-assets/9700_w21_ms_43-p15.png" ] }, { "id": "9700-2021-on-43-q07", "question_id": "9700-2021-on-43-q07", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 base / nucleotide, insertion / deletion / substitution ;\n2 frameshift / changed reading frame ;\n3 ref. to stop codon ;\n4 changes / different, primary structure / amino acid sequence ;\n5 changes / different, folding / 3D shape / 3o structure, of enzyme / protein ;\n6 active site does not, bind / fit, substrate / complex molecules ;\n© UCLES 2021 Page 15 of 21\n\n7(b) 1 key e.g. H = normal (allele) h = Hunter (syndrome allele) ; 5\nparental normal male normal female\nphenotype\n2 parental XHY XH Xh ;\ngenotype\ngametes ( XH Y XH Xh )\n3 offspring XH XH XH Xh XH Y Xh Y ;\ngenotypes\n4 offspring normal normal / carrier normal Hunter S ;\nphenotypes female female male male\n5 probability 0.25 / 25% / 1 in 4 ;\n© UCLES 2021 Page 16 of 21", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p15.png", "../answer-assets/9700_w21_ms_43-p16.png" ] }, { "id": "9700-2021-on-43-q08", "question_id": "9700-2021-on-43-q08", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 5, "status": "available", "reason": null, "text": "8 any five from: 5\n1 due to (Great Central) Valley / during migration, populations / they, are separated / geographically isolated ;\n2 no, mating / breeding / gene flow, between, them / populations ;\n3 different (named), selection pressures / environments / conditions / habitats ;\n4 different mutations ;\n5 natural selection ;\n6 genetic drift / founder effect ;\n7 change in allele frequency OR change in / different, gene pool ;\n8 leads to different, morphological / behavioural / biochemical / physiological, features ;\n9 allopatric speciation ;\n© UCLES 2021 Page 17 of 21", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p17.png" ] }, { "id": "9700-2021-on-43-q09", "question_id": "9700-2021-on-43-q09", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 15, "status": "available", "reason": null, "text": "9(a) any seven from 7\n1 (H+) carrier / pump (protein), in cell surface membrane (of guard cell) ;\n2 hydrogen ions / protons / H ions / H+, leave / exit (cell) ;\n3 using, energy / ATP ;\n4 low H+ (in cell) / more negative charge (than outside) ;\n5 K+ channel (proteins) open ;\n6 K+, move into / enter, cell (by facilitated diffusion) ;\n7 Cl – ions, move into / enter (cell) ;\n8 water / solute, potential of cell decreases ;\n9 water moves in (to cell) by osmosis ;\n10 cell / vacuole, volume increases ;\n11 (cells) are / become, turgid ;\n12 thick inner cell wall (of guard cell) ;\n13 AVP ;\n© UCLES 2021 Page 18 of 21\n\n9(b) any eight from: 8\n1 C4, plants / pathway ;\n2 stop / decrease, photorespiration ;\n3 mesophyll cells form (tightly packed) ring ;\n4 around / surrounding, bundle sheath (cells) ;\n5 (initial) CO carbon, fixation in mesophyll and Calvin cycle in bundle sheath ;\n2 /\n6 RuBP / rubisco, in bundle sheath (cells) ;\n7 oxygen / air, cannot reach, RuBP / rubisco / bundle sheath ;\n8 CO combines with, PEP / PEP carboxylase (in mesophyll) ;\n2\n9 to form, oxaloacetate / malate ;\n10 (malate) releases carbon dioxide in bundle sheath (cells) ;\n11 RuBP, carboxylated / reacts with carbon dioxide ;\n12 PEP carboxylase has high optimum temperature / tolerates high temperatures ;\n© UCLES 2021 Page 19 of 21", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p18.png", "../answer-assets/9700_w21_ms_43-p19.png" ] }, { "id": "9700-2021-on-43-q10", "question_id": "9700-2021-on-43-q10", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 15, "status": "available", "reason": null, "text": "10(a) any nine from: 9\n1 Na+ / sodium ion, channels open ;\n2 Na+ / sodium ions, enter, neurone / axon / (nerve) cell ;\n3 membrane (potential) becomes, positive / +40 mV / depolarised ;\n4 (repolarisation / after peak) Na+ / sodium ion, channels close ;\n5 K+ / potassium ion, channels open ;\n6 K+ / potassium ions, leave / move out (of cell) ;\n7 membrane (potential) becomes, negative / –90 mV / repolarised ;\n8 local circuits ;\n9 myelin sheath / Schwann cells, insulates / stops ion movement ;\n10 action potential / depolarisation, only occurs at nodes of Ranvier ;\n11 saltatory conduction ;\n12 fast transmission (of, action potential / impulse) ;\n13 one-way transmission (of, action potential / impulse) ;\n14 AVP ;\n© UCLES 2021 Page 20 of 21\n\n10(b) any six from: 6\n1 maintain / keep / regulate, internal, environment / conditions ;\n2 within, narrow / set, limits or around, optimum value / set point / norm ;\n3 low (body) temperature and consequence ;\n4 high (body) temperature and consequence ;\n5 low blood glucose (concentration) and consequence ;\n6 high blood glucose concentration and consequence ;\n7 low, (blood) water potential / ψ, and consequence ;\n8 high, (blood) water potential / ψ, and consequence ;\n© UCLES 2021 Page 21 of 21", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_43-p20.png", "../answer-assets/9700_w21_ms_43-p21.png" ] }, { "id": "9700-2021-on-51-q01", "question_id": "9700-2021-on-51-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a)(i) independent variable temperature ; 2\ndependent variable volume of carbon dioxide / time to collect stated or fixed volume of CO ;\n2\n\n1(a)(ii) idea that: 1\nensures glucose and yeast are, uniformly distributed / homogeneously mixed / evenly mixed / completely mixed / AW ;\n\n1(a)(iii) any seven from: 7\n1 use a minimum of five different temperatures ;\n2 state a suitable range of identified temperatures ;\n3 idea of same / constant / stated / standardised / known, volume of, yeast-glucose / mixture (in the test-tube) ;\n4 method of maintaining a, constant / stated, temperature ;\n5 leave mixture to equilibrate to (each) temperature ;\n6 leave for, set time / stated time, and measure volume (of carbon dioxide)\nor\ntime how long to collect same volume (of carbon dioxide) from (each) sample ;\n7 use a control using, killed yeast / water replacing yeast ;\n8 ref. to a minimum of, two repeats / three replicates (for each temperature), and calculating means ;\n9 idea of repeat investigation with narrower range of temperatures (around that which seems the one giving maximum\nrate) ;\n10 low risk ;\n‘medium risk’ needs hazard and risk and precaution.\nA yeast + allergy/irritant + gloves / mask / goggles /PPE\n11 AVP e.g. maintaining a constant pH and using a buffer ;\n© UCLES 2021 Page 7 of 11\n\n1(a)(iv) 1 horizontal axis labelled temperature / oC 2\nand\nvertical axis labelled volume of carbon dioxide / cm3 / mm3 ;\n2 curve starts low, reaches a maximum and then decreases ;\n\n1(b) 1 flask 2 (provides the evidence) as in C. tropicalis there is lower CO (production / volume / AW) ; 3\n2\n2 (for flask 2, C. tropicalis compared to S. cerevisiae) 65% v 93% (after 30 minutes) CO as % of maximum or\n2\nmanipulated figure i.e. 28% different ;\n3 idea that: when transferred from conditions with oxygen to conditions with no oxygen yeasts have to use fermentation /\nanaerobic respiration but C. tropicalis does so at a much slower rate (as no Crabtree effect) thus less CO produced\n2\nora ;\n© UCLES 2021 Page 8 of 11", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_51-p07.png", "../answer-assets/9700_w21_ms_51-p08.png" ] }, { "id": "9700-2021-on-51-q02", "question_id": "9700-2021-on-51-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "2(a) idea of no (clear), relationship / trend ; 1\nor\nas latitude increases, (bird) species diversity / numbers of (bird) species, (slightly) decreases / (might) show a downward\ntrend ;\n\n2(b)(i) any three from: 3\n1 data (for latitude and number of species) is, paired / linked ;\n2 number of bird species and latitude / (i.e. the data points) within samples are independent of each other ;\n3 the data, is ordinal / is interval / is discrete / can be ranked ;\n4 (scatter) graph / Fig. 2.2, suggests a, (decreasing) relationship / correlation ;\n5 there are, 17 (paired) observations / more than 5 (paired) observations ;\n6 idea that bird species selected randomly / AW ;\n\n2(b)(ii) idea that 1\nthere is no, correlation / relationship, between latitude and the number of (bird) species ;\n\n2(b)(iii) any four from: 4\n1 critical value (for p = 0.05%) = 0.485\nor\ncritical value for p = 0.01% = 0.615 ;\n2 value for r / calculated value, is < than critical value ;\ns\n3 null hypothesis is accepted ;\n4 there is no significant correlation (between latitude and number of bird species) ;\n5 there is a (weak) negative correlation (between latitude and number of bird species as shown by the negative value for\nr ) ;\ns\n© UCLES 2021 Page 9 of 11\n\n2(c) any three from 3\nall marking points are ideas that:\nlimitations of the data\n1 only used counts of bird species (may not apply to all species) ;\n2 do not know the, number of individuals of each species / relative abundance of each species / species evenness ;\nlimitations of sampling\nbirds\n3 hard to identify some (bird) species / miss some (bird) species / some (bird) species look similar / miss birds that fly\naway / birds migrate / only resident birds or species counted / qualified ref to volunteers / AW ;\nlatitudes sampled\n4 nothing above 40N / nothing before 37N / need wider range of latitudes / AW ;\n5 no data on latitudes south of the equator ;\nsampling sites\n6 not random / only sampled in certain locations / sample locations do not cover the whole of the peninsula / many near\nthe coast / locations may not be representative of the peninsula / only 17 sites / sampling sites do not extend beyond\nthe peninsular / AW ;\nhabitats\n7 no information on habitats (at locations) / not all location may be equally suited for birds / different habitats have\ndifferent conditions / AW ;\ntimings\n8 only sampled, on one day / in one year / sampled in, winter / one season ; ora\n© UCLES 2021 Page 10 of 11\n\n2(d) any three from: 3\n1 catch birds within area and count total captured and mark and release them ;\n2 detail\ne.g. idea of: marking technique not, harmful / too obvious\ne.g. idea of: giving time for populations to mix before second sample taken – days or weeks not more ;\n3 catch second sample and count total number of birds and number of marked birds ;\n4 ref. to Lincoln / Petersen, index ;\n© UCLES 2021 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_51-p09.png", "../answer-assets/9700_w21_ms_51-p10.png", "../answer-assets/9700_w21_ms_51-p11.png" ] }, { "id": "9700-2021-on-52-q01", "question_id": "9700-2021-on-52-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 17, "status": "available", "reason": null, "text": "1(a)(i) independent variable 2\ntype of sugar\nor\nglucose / monosaccharide and maltose / disaccharide ;\ndependent variable\nheight / length, of gas ;\n\n1(a)(ii) to allow yeast / cells, to be evenly distributed ; 1\n\n1(a)(iii) any seven from: 7\n1 same / stated, concentration of glucose and maltose solutions ;\n2 same / stated, volume of each sugar solution ;\n3 same / stated, volume of yeast suspension (for each tube) / equally divide yeast suspension between (each tube) ;\n4 same / stated, volume of water in each (large) tube ;\n5 method of maintaining a constant temperature ;\n6 maintaining a constant pH and use a buffer ;\n7 measure / record, height of gas / liquid, in set time\nor\nmeasure / record, time taken, to reach a set height of gas / liquid ;\n8 use of a ruler / AW for measuring gas / liquid ;\n9 control, using killed yeast / replace yeast with water ;\n10 repeat at least twice / three replicates, and finding mean (for at least one sugar) ;\n11 low risk ;\n© UCLES 2021 Page 8 of 11\n\n1(b)(i) any one from: 1\ndivide the volume of gas collected in a stated time, by the (same) time ;\n1÷ time to reach a stated volume of gas ;\nuse a tangent to the line and divide volume by time / calculate gradient ;\n\n1(b)(ii) any three from: 3\n1 rate of respiration is higher for glucose (than maltose) / ora ;\n2 initial rate of reaction / respiration faster ;\n3 gas / CO ,production is higher with glucose / ora ;\n2\n4 maltose is broken down before it can be respired / glucose can be respired immediately ;\n5 maltase / enzyme, needed to break down maltose ;\n\n1(c) any three from: 3\n1 not subjective / ora ;\n2 more accurate / ora ;\n3 more precise / ora ;\n4 can continuously record data (with data logger / computer) ;\n5 meter can be used if colour blind / ora ;\n6 meter does not pose a risk or hazard / ora ;\n© UCLES 2021 Page 9 of 11", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_52-p08.png", "../answer-assets/9700_w21_ms_52-p09.png" ] }, { "id": "9700-2021-on-52-q02", "question_id": "9700-2021-on-52-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "2(a) any one from: 1\nfrog, age / size / mass / stage of maturity / from same population ;\nlight intensity ;\nhumidity ;\ntime of day ;\ntime of year ;\nduration of recording ;\nbackground noise ;\n\n2(b) as (body) temperature increases the interval between calls decreases ; 1\n\n2(c)(i) any three from: 3\n1 data (for temperature and calls) is, paired / linked ;\n2 data is continuous ;\n3 data shows normal distribution ;\n4 scatter diagram, suggests a linear, relationship / correlation ;\n5 there are at least five (paired) observations ;\n\n2(c)(ii) there is no, correlation / relationship, between the intervals between calls and temperature ; 1\n\n2(c)(iii) any two from: 2\nsignificant because\n1 (critical value for p = 0.05 / 5% is) 0.279\nor\n(critical value for p = 0.01 / 1% is) 0.361 ;\n2 value for r / 0.717, is > than critical value (so null hypothesis is rejected / accept the alternative hypothesis) / ora ;\n© UCLES 2021 Page 10 of 11\n\n2(d) any two from: 2\n1 duration of each call ;\n2 number of calls in a set time ;\n3 number / frequency, of pulses, within each call ;\n4 length of time between pulses within each call ;\n5 sound frequency (kHz) / pitch ;\n6 duration of each pulse ;\n\n2(e) any three from: 3\n1 capture frogs and count / find number / record number and mark and release them ;\n2 suitable marking so not harmful / too obvious / not removed\nor\nappropriate time between first and second capture so frogs time to mix ;\n3 capture second sample and count / find number / record number of frogs and count / find number / record number, of\nmarked frogs ;\n4 use Lincoln / Petersen, index ;\n© UCLES 2021 Page 11 of 11", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_52-p10.png", "../answer-assets/9700_w21_ms_52-p11.png" ] }, { "id": "9700-2021-on-53-q01", "question_id": "9700-2021-on-53-q01", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a)(i) independent variable temperature ; 2\ndependent variable volume of carbon dioxide / time to collect stated or fixed volume of CO ;\n2\n\n1(a)(ii) idea that: 1\nensures glucose and yeast are, uniformly distributed / homogeneously mixed / evenly mixed / completely mixed / AW ;\n\n1(a)(iii) any seven from: 7\n1 use a minimum of five different temperatures ;\n2 state a suitable range of identified temperatures ;\n3 idea of same / constant / stated / standardised / known, volume of, yeast-glucose / mixture (in the test-tube) ;\n4 method of maintaining a, constant / stated, temperature ;\n5 leave mixture to equilibrate to (each) temperature ;\n6 leave for, set time / stated time, and measure volume (of carbon dioxide)\nor\ntime how long to collect same volume (of carbon dioxide) from (each) sample ;\n7 use a control using, killed yeast / water replacing yeast ;\n8 ref. to a minimum of, two repeats / three replicates (for each temperature), and calculating means ;\n9 idea of repeat investigation with narrower range of temperatures (around that which seems the one giving maximum\nrate) ;\n10 low risk ;\n‘medium risk’ needs hazard and risk and precaution.\nA yeast + allergy/irritant + gloves / mask / goggles /PPE\n11 AVP e.g. maintaining a constant pH and using a buffer ;\n© UCLES 2021 Page 7 of 11\n\n1(a)(iv) 1 horizontal axis labelled temperature / oC 2\nand\nvertical axis labelled volume of carbon dioxide / cm3 / mm3 ;\n2 curve starts low, reaches a maximum and then decreases ;\n\n1(b) 1 flask 2 (provides the evidence) as in C. tropicalis there is lower CO (production / volume / AW) ; 3\n2\n2 (for flask 2, C. tropicalis compared to S. cerevisiae) 65% v 93% (after 30 minutes) CO as % of maximum or\n2\nmanipulated figure i.e. 28% different ;\n3 idea that: when transferred from conditions with oxygen to conditions with no oxygen yeasts have to use fermentation /\nanaerobic respiration but C. tropicalis does so at a much slower rate (as no Crabtree effect) thus less CO produced\n2\nora ;\n© UCLES 2021 Page 8 of 11", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_53-p07.png", "../answer-assets/9700_w21_ms_53-p08.png" ] }, { "id": "9700-2021-on-53-q02", "question_id": "9700-2021-on-53-q02", "subject": "9700", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "2(a) idea of no (clear), relationship / trend ; 1\nor\nas latitude increases, (bird) species diversity / numbers of (bird) species, (slightly) decreases / (might) show a downward\ntrend ;\n\n2(b)(i) any three from: 3\n1 data (for latitude and number of species) is, paired / linked ;\n2 number of bird species and latitude / (i.e. the data points) within samples are independent of each other ;\n3 the data, is ordinal / is interval / is discrete / can be ranked ;\n4 (scatter) graph / Fig. 2.2, suggests a, (decreasing) relationship / correlation ;\n5 there are, 17 (paired) observations / more than 5 (paired) observations ;\n6 idea that bird species selected randomly / AW ;\n\n2(b)(ii) idea that 1\nthere is no, correlation / relationship, between latitude and the number of (bird) species ;\n\n2(b)(iii) any four from: 4\n1 critical value (for p = 0.05%) = 0.485\nor\ncritical value for p = 0.01% = 0.615 ;\n2 value for r / calculated value, is < than critical value ;\ns\n3 null hypothesis is accepted ;\n4 there is no significant correlation (between latitude and number of bird species) ;\n5 there is a (weak) negative correlation (between latitude and number of bird species as shown by the negative value for\nr ) ;\ns\n© UCLES 2021 Page 9 of 11\n\n2(c) any three from 3\nall marking points are ideas that:\nlimitations of the data\n1 only used counts of bird species (may not apply to all species) ;\n2 do not know the, number of individuals of each species / relative abundance of each species / species evenness ;\nlimitations of sampling\nbirds\n3 hard to identify some (bird) species / miss some (bird) species / some (bird) species look similar / miss birds that fly\naway / birds migrate / only resident birds or species counted / qualified ref to volunteers / AW ;\nlatitudes sampled\n4 nothing above 40N / nothing before 37N / need wider range of latitudes / AW ;\n5 no data on latitudes south of the equator ;\nsampling sites\n6 not random / only sampled in certain locations / sample locations do not cover the whole of the peninsula / many near\nthe coast / locations may not be representative of the peninsula / only 17 sites / sampling sites do not extend beyond\nthe peninsular / AW ;\nhabitats\n7 no information on habitats (at locations) / not all location may be equally suited for birds / different habitats have\ndifferent conditions / AW ;\ntimings\n8 only sampled, on one day / in one year / sampled in, winter / one season ; ora\n© UCLES 2021 Page 10 of 11\n\n2(d) any three from: 3\n1 catch birds within area and count total captured and mark and release them ;\n2 detail\ne.g. idea of: marking technique not, harmful / too obvious\ne.g. idea of: giving time for populations to mix before second sample taken – days or weeks not more ;\n3 catch second sample and count total number of birds and number of marked birds ;\n4 ref. to Lincoln / Petersen, index ;\n© UCLES 2021 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2021-Oct-Nov/ms/9700_w21_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2021-oct-nov/9700_w21_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w21_ms_53-p09.png", "../answer-assets/9700_w21_ms_53-p10.png", "../answer-assets/9700_w21_ms_53-p11.png" ] }, { "id": "9700-2022-m-42-q01", "question_id": "9700-2022-m-42-q01", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) any two from: 2\n1 high birth rate / short generation time / AW ;\n2 few / no, predators ;\n3 little competition ;\n4 plenty of food available / wide range of food types eaten / omnivore ;\n5 no / fewer, diseases ;\n6 well adapted / no selection pressures against them ; A description\n\n1(a)(ii) any three from: 3\n1 directional selection ;\n2 blonde spines have a selective advantage / described / AW ;\n3 allele frequency for blonde spines increases / increased homozygosity (for recessive or blonde allele) ;\n4 inbreeding ;\n5 small gene pool (at start) / little genetic variation ;\n6 founder effect / genetic drift / bottleneck effect ; A description\n© UCLES 2022 Page 5 of 22\n\n1(b) any four from: 4\naccept local for native throughout\nbecause alien species:\n1 compete with native species ;\n2 for, food / same niche / light / resources\nor\nreduce food source of native species ;\n3 feed on / predators of, native species ;\n4 can cause extinction in native species ;\n5 can breed more successfully than native species ;\n6 often have no, natural predator / grazers ;\n7 may disrupt, habitats / ecosystems / food webs / food chains ;\nignore environment\n8 cause reduction in biodiversity ;\n9 may introduce disease ;\n© UCLES 2022 Page 6 of 22", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p05.png", "../answer-assets/9700_m22_ms_42-p06.png" ] }, { "id": "9700-2022-m-42-q02", "question_id": "9700-2022-m-42-q02", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\n1 no / less, ATP for the, sodium-potassium pump / active transport of Na+ and K+ ;\n2 reduces / prevents, (re-establishment of) resting potential ;\n3 reduces transmission of action potential (along the axon) ;\n\n2(a)(ii) any two from: 2\n1 decreases (speed) / lower (speed than expected) ;\n2 in both, nerves / median and peroneal / arm and leg ;\n3 processed data quote ; e.g. median mean 43 m s–1 / peroneal mean 31.3 m s–1\n4 AVP ; e.g. person 1 not affected so much\n\n2(a)(iii) any two from: 2\n1 takes longer for impulses to reach, neuromuscular junction / muscles ;\n2 fewer / slower, muscle contractions ;\n3 walking problem described ; e.g. reduced muscle control / walks slower / stumbles / trips\n4 slower reflexes ;\n© UCLES 2022 Page 7 of 22\n\n2(b) accept ‘neurone activity’ for ‘balance time’ throughout 4\n(had benefit is justified because):\n1 (mice with therapy) rate of decline of balance time, slower / less steep, from, 18 to 20 months / initially / at the start\nor\n(mice with therapy) have a longer balance time ;\n(not cure is justified since):\n2 (mice with therapy and mice with no therapy)\nhave, same / similar, balance time, at 23 months / at the end\nor\nmice with therapy have a, downwards trend / decrease in balance time\nor\nmice with therapy have shorter balance time (compared to mice without GAN) ;\n(results are not affected by age is not justified because):\n3 mice without GAN increase balance time, during the experiment / with age\nor\nbalance time decreases for mice with GAN, during the experiment / with age ;\n4 comparative figures to support any marking point\nor\nref. to need for statistical test ;\n© UCLES 2022 Page 8 of 22", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p07.png", "../answer-assets/9700_m22_ms_42-p08.png" ] }, { "id": "9700-2022-m-42-q03", "question_id": "9700-2022-m-42-q03", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 14, "status": "available", "reason": null, "text": "3(a) any five from: 5\nmax four from mp1–mp6:\n1 (sickle cell anaemia is) homozygous recessive ;\n2 ref. to beta / β, globin / polypeptide\nor\nHBB (allele / gene) ;\n3 base / nucleotide, substitution\nor\nmis-sense mutation\nor\nchange in, triplet / codon\nor\nGAG to GTG / A to T ;\n4 causes, change in amino acid (sequence) / glutamic acid to valine ;\n5 valine is non-polar ;\n6 causes change in, 3D shape / tertiary structure / quaternary structure / globular structure (of haemoglobin) ;\n7 haemoglobin has lower affinity for oxygen ;\n8 (in red blood cells) haemoglobin, less soluble / sticks together / forms fibres ;\n9 (red blood) cells become sickle shaped ;\n© UCLES 2022 Page 9 of 22\n\n3(b)(i) decrease (in ADH) (accept no ADH secreted) 1\nand\nreduce water reabsorption (in the collecting duct)\nor\ndecrease (in ADH)\nand\nincreased volume of / more dilute, urine (formed) ;\n\n3(b)(ii) idea that fluid / water, is forced (from blood) into alveoli ; R diffusion / osmosis 1\n\n3(c) any four from: 4\ndescribe:\n1 having kidney disease increases the risk of TACO ; ora\n2 AKI has highest risk (of TACO) ;\n3 data quote to support mp1 (comparison) ;\nreasons:\n4 kidney disease reduces ability to remove excess water ;\n5 more water retained increases blood volume ;\n6 AVP ; e.g. CKD + D less risk as dialysis helps to restore water volume\n© UCLES 2022 Page 10 of 22\n\n3(d) any two from: 3\n1 fewer sodium (ions) reabsorbed / more sodium (ions) in filtrate ;\n2 decreases water potential of filtrate\nor\nincreases water potential of the medulla ;\n3 less water reabsorbed, by osmosis / down water potential gradient ;\n4 increases volume of urine ;\nplus:\n5 so blood volume (from transfusion) is reduced ;\n© UCLES 2022 Page 11 of 22", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p09.png", "../answer-assets/9700_m22_ms_42-p10.png", "../answer-assets/9700_m22_ms_42-p11.png" ] }, { "id": "9700-2022-m-42-q04", "question_id": "9700-2022-m-42-q04", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 15, "status": "available", "reason": null, "text": "4(a)(i) label line to where white chromatid crosses over grey chromatid ; 1\n\n4(a)(ii) any four from: 4\n1 (crossing over is) between non-sister chromatids ;\n2 (non-sister chromatids have) different combinations of alleles ;\n3 exchange alleles ;\n4 (chromatids have) new combinations of alleles ;\n5 linkage groups broken ;\n6 idea that gametes have unique combination of alleles ;\n7 random fusion of gametes (during fertilisation) ;\n\n4(b)(i) any two from: 2\n1 (first) generation of offspring (from parental cross) ;\n2 (parents are) homozygous / true bred / pure bred / pure breeding ;\n3 F1 generation will be heterozygous ;\n© UCLES 2022 Page 12 of 22\n\n4(b)(ii) 3\nexpected (𝑂−𝐸)(cid:2870)\nphenotype O E O – E (O – E)2\nratio\n𝐸\nfull band\nand 9 99 76.5 22.5 506.25 6.62\nrays\nfull band\nand 3 21 25.5 –4.5 20.25 0.79\nno rays\nbroken band\nand 3 8 25.5 –17.5 306.25 12.01\nrays\nbroken band\nand 1 8 8.5 –0.5 0.25 0.03\nno rays\n1 mark for E and O – E correct ;\n(𝑂−𝐸)2\n1 mark for (O – E)2 and correct ;\n𝐸\nχ2\n= 19.45 ;\necf for 1 mistake in one box\n© UCLES 2022 Page 13 of 22\n\n4(b)(iii) any three from: 3\n1 19.45 / chi-squared value, is greater than, 7.81 / critical value (at p = 0.05) ;\n2 results are / observed ratio is, significantly different to expected ratio ;\n3 so differences are not due to chance ;\n4 due to, increase in full band phenotypes / decrease in broken band phenotypes ;\n\n4(b)(iv) any two from: 2\n1 epistasis ;\n2 linkage ;\n3 lethal allele ;\n4 chance deviations ;\n5 environmental effects ;\n6 mutations ;\n7 small sample size ;\n© UCLES 2022 Page 14 of 22", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p12.png", "../answer-assets/9700_m22_ms_42-p13.png", "../answer-assets/9700_m22_ms_42-p14.png" ] }, { "id": "9700-2022-m-42-q05", "question_id": "9700-2022-m-42-q05", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 8, "status": "available", "reason": null, "text": "5(a)(i) haemophilia (A) ; 1\n\n5(a)(ii) any two from: 2\naccept ora throughout\n1 large / unlimited, supply ;\n2 no risk of infection ;\n3 no / fewer, ethical issues ;\n4 less chance of, rejection / immune response / allergic response / side effects ;\n5 cheap / quick, to produce ;\n6 no need to wait for donor ;\n\n5(b)(i) reverse transcriptase ; 1\n\n5(b)(ii) 1 genes cut from (donor) DNA ; 2\n2 genes synthesised (chemically) from nucleotides ;\n\n5(c) any two from: 2\n1 required, for gene expression / to start transcription ;\n2 (so) transcription factor can bind (to promoter) ;\n3 so RNA polymerase can bind (to promoter) ;\n© UCLES 2022 Page 15 of 22", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p15.png" ] }, { "id": "9700-2022-m-42-q06", "question_id": "9700-2022-m-42-q06", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "6(a)(i) 1 CO uptake below zero / CO released / CO uptake is negative / CO uptake is –1.6 μmol m–2 s–1 ; 3\n2 2 2 2\nplus any two from:\n2 little photosynthesis occurring / AW ; R no photosynthesis\n3 due to low light intensity ;\n4 rate of respiration higher than rate of photosynthesis ;\nA idea that there is more respiration than photosynthesis\n\n6(a)(ii) any three from: 3\n1 as light intensity increases rate of CO uptake increases / AW ;\n2\n2 data quote to support mp1 ; e.g. carbon uptake is –0.2 μmol m–2 s–1 at 2000 lux and 6.5 μmol m–2 s–1 at 7000 lux\n3 (because) rate of, photosynthesis / light-dependent reactions / light-independent reactions, increases ;\n4 light intensity is limiting factor ;\n\n6(a)(iii) light intensity is no longer limiting 1\nor\ncarbon dioxide concentration / temperature, now limiting ;\n\n6(b)(i) hydrolytic / extracellular / protease / proteinase / peptidase / AW ; 1\n\n6(b)(ii) amino acid(s) / proteins / nucleotides ; 2\nglycerate-3-phosphate / GP\nor\ntriose phosphate / TP ;\n© UCLES 2022 Page 16 of 22", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p16.png" ] }, { "id": "9700-2022-m-42-q07", "question_id": "9700-2022-m-42-q07", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "7(a) any seven from: 7\n1 reduced, NAD / FAD ;\n2 releases hydrogen / hydrogen splits into proton and electron ;\n3 ref. to, inner mitochondrial membrane / cristae ;\n4 electrons pass through, electron transport chain / ETC ;\n5 ref. to energy release ;\n6 protons transferred, through inner membrane / into intermembrane space ;\n7 proton gradient established / high proton concentration in intermembrane space ;\n8 protons diffuse through ATP synth(et)ase ;\n9 ATP produced from ADP and Pi ;\n10 ref. to chemiosmosis ;\n11 oxygen acts as final electron acceptor (to form water) / described ;\n© UCLES 2022 Page 17 of 22\n\n7(b) any four from: 4\n1 population B produces more ATP (than population A) ; ora\n2 production of ATP increases at a higher rate for population B (than for population A) ; ora\n3 paired data quote ;\n4 population B carries out, glycolysis / substrate-linked phosphorylation, and oxidative phosphorylation ;\n5 population A carries out (only) glycolysis / respiration in anaerobic conditions / (ethanol) fermentation / substrate-linked\nphosphorylation\nor\npopulation A cannot carry out oxidative phosphorylation ;\nQuestion Answer Marks", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p17.png", "../answer-assets/9700_m22_ms_42-p18.png" ] }, { "id": "9700-2022-m-42-q08", "question_id": "9700-2022-m-42-q08", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 8, "status": "available", "reason": null, "text": "8(a) 1 sympatric ; 3\nany two from:\n2 no geographical barrier / not geographically isolated ;\n3 ref. to behavioural isolation / described ;\n4 ref. to reproductive isolation / described ;\n© UCLES 2022 Page 18 of 22\n\n8(b) any three from: 3\nora in terms of easier for crop yields\n1 longer time to, grow / mature ;\n2 fewer offspring (per cross / AW) ;\n3 feature can only be measured in, about 50% of offspring / females ;\n4 milk yield must be measured over period of time ;\n5 ref. to ethical issues ;\n6 ref. to difficulty in identifying suitable males for use in crosses ;\n7 cattle require more, care / support\nor\nmore expensive ;\n8 AVP ; e.g. more dangerous to carry out breeding of large cattle\n\n8(c) any two from: 2\n1 mass / quantity / size ;\n2 disease resistance ;\n3 resistance to, insects / pests ;\n4 rate of growth ;\n5 drought resistance ;\n6 resistance to herbicides ;\n7 AVP ; e.g. resistance to, flooding / wind\n© UCLES 2022 Page 19 of 22", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p18.png", "../answer-assets/9700_m22_ms_42-p19.png" ] }, { "id": "9700-2022-m-42-q09", "question_id": "9700-2022-m-42-q09", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 8, "status": "available", "reason": null, "text": "9(a) 1 individuals (within a population) can, breed / mate / reproduce ; 3\n2 to produce fertile offspring ;\n3 are reproductively isolated (from other species) / AW ;\n\n9(b) any one from: 1\n1 for organisms that, do not breed sexually / are asexual ;\n2 for, fossil / extinct, organisms ;\n3 morphological differences are easier to determine ;\n4 often not possible to observe reproductive behaviour ;\n5 time required for mating behaviour may take too long (to be observed) / not possible to achieve conditions in which\nmating can occur (while being observed) ;\n© UCLES 2022 Page 20 of 22\n\n9(c) any four from: 4\nmax three:\n1 both are prokaryotes\nor\nboth have no, nucleus / (double) membrane-bound organelles ;\n2 both have circular DNA ;\n3 both have 70S ribosomes ;\n4 both reproduce by, binary fission / budding / fragmentation ;\nmax three:\n5 bacteria cell wall made of peptidoglycan whereas Archaea cell wall does not have peptidoglycan ;\n6 bacteria cell membrane has ester-linked lipids whereas Archaea cell membrane has ether-linked lipids ;\n7 have different ribosomal RNA ;\n8 Bacteria do not have (DNA associated with) histones whereas Archaea do have (DNA associated with) histones ;\n9 Bacteria form spores whereas Archaea do not form spores ;\n© UCLES 2022 Page 21 of 22", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p20.png", "../answer-assets/9700_m22_ms_42-p21.png" ] }, { "id": "9700-2022-m-42-q10", "question_id": "9700-2022-m-42-q10", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "10(a) A – chloroplast ; 3\nB – vacuole ;\nC – cell wall ; A cell surface membrane\n\n10(b) any four from: 4\n1 abscisic acid binds to receptors on cell surface membrane (of guard cell) ;\n2 proton pumps are inhibited / AW ;\n3 stimulates Ca2+ uptake / opens Ca2+ channels ;\n4 Ca2+ acts as second messenger ;\n5 K+ diffuses out of the (guard) cell ;\n6 water potential of (guard) cell increases ;\n7 water leaves (guard) cell, by osmosis / down water potential gradient ;\n8 (guard) cell becomes flaccid / cell volume decreases (so stoma closes) ;\n© UCLES 2022 Page 22 of 22", "source_pages": [ 22 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_42-p22.png" ] }, { "id": "9700-2022-m-52-q01", "question_id": "9700-2022-m-52-q01", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "1(a) idea of replace (live) water plant / Egeria densa with: 1\ndead / AW, water plant (of the same volume)\nor\nsterile / inert / glass beads / AW, material (of same volume)\nor\npond water with sodium hydrogencarbonate (no water plant) ;\n\n1(b)(i) any seven from: 7\n1 use, lamp / AW, at different distances from plant\nor\nuse, lamp / AW, with different power ratings / wattages (at same distances) ;\n2 use a minimum of five, different / stated, light intensities / AW ;\n3 use, a light meter / an app, to measure light intensity ;\n4 carry out investigation, in a darkened room / with no other light source / AW ;\n5 measure / note / record, the distance the, meniscus / AW, moves along the capillary tube / scale, in a fixed time\nor\nmeasure / note / record, the time the, meniscus / AW, takes to travel, a fixed distance on the capillary tube / scale ;\n6 use, same / stated, length of water plant / Egeria densa ;\n7 use, same / stated, mass / concentration, of sodium hydrogencarbonate ;\n8 use a method to reduce heating effect of lamp ;\n9 idea of equilibration / acclimatisation, of, water plant / Egeria densa / whole apparatus (to each light intensity) ;\n10 use at least three measurements (at each light intensity / AW,) and calculate a mean ;\n11 safety comment with hazard, risk and precaution ;\n© UCLES 2022 Page 5 of 9\n\n1(b)(ii) horizontal axis labelled: 3\ndistance from light bulb / light intensity / power rating of light bulb / AW\nand\nvertical axis labelled:\nrate of photosynthesis / rate of movement of meniscus / distance meniscus moved (in set time) / time taken for meniscus to\nmove (a set distance) ;\ncorrect units:\n(distance from light bulb) cm / mm\n(light intensity) lux / cd (candela) / alternative units\n(power rating of bulb) W\nand\n(rate of photosynthesis) cm min–1 / mm min–1 / cm s–1 / mm s–1\n(rate of movement of meniscus) cm min–1 / mm min–1 / cm s–1 / mm s–1\n(distance meniscus moved) cm / mm\n(time for meniscus to move) min / s ;\nappropriately shaped line ;\npositive gradient (may level off at higher light intensities) for, light intensity / power rating of light bulb, against, rate of\nphotosynthesis / rate of movement / distance moved\nnegative gradient (may level off at higher light intensities) for, light intensity / power rating of light bulb against time to\nmove set distance\nnegative gradient (may level off at shorter distances) for distance from light bulb against, rate of photosynthesis / rate of\nmovement / distance moved\npositive gradient (may level off at shorter distances) for distance from light bulb against time to move set distance\n\n1(c)(i) 0.88 ; 1\n© UCLES 2022 Page 6 of 9\n\n1(c)(ii) idea of: 1\n1 difficulty in achieving, concentrated / not spread out / AW, spot of extract ;\n2 each pigment, spreads out during migration / gives long streak / runs into each other / overlaps / AW (so difficult to\nmeasure accurately) ;\n3 pigment may, fade / be too pale to see clearly / AW, (so difficult to measure accurately) ;\n4 uniformity / quality / grade, of (chromatography) paper ;\n5 type of solvent ;\n6 different, laboratory / ambient / AW, conditions ;\nQuestion Answer Marks", "source_pages": [ 5, 6, 7 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_52-p05.png", "../answer-assets/9700_m22_ms_52-p06.png", "../answer-assets/9700_m22_ms_52-p07.png" ] }, { "id": "9700-2022-m-52-q02", "question_id": "9700-2022-m-52-q02", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "2(a) type of woodland / 1\npresence or absence of native tree species / AW ;\n\n2(b)(i) three standardised variables ; 1\nfrom:\n25 traps / same number, of traps in each area\n25 traps / same number, of traps in each trapping session\nmass / 10 g, food (for rodents) / bait\ntime interval / 24 hours, before checking trap\nfour / same number of, days / sessions (for each area)\nmonth / April / season / time of year\n\n2(b)(ii) any suitable method of generating, random numbers / coordinates / positions ; 2\nuse the numbers generated, as coordinates / grid reference, to locate each trap site ;\n© UCLES 2022 Page 7 of 9\n\n2(c)(i) 0.716 / 0.717 / 0.718 ; ; 2\nif answer is incorrect, ALLOW 1 mark max for:\ncorrect answer to, two significant figures / more than three significant figures\n1 – calculated Σ(n/N)2\n\n2(c)(ii) any three from: 3\nconclusions:\n1 the biodiversity / (species) diversity, in the area with a mixture of native tree species and saltcedar trees is,\ngreater / higher / AW, than the, biodiversity / (species) diversity, in the area of only saltcedar trees ;\n2 the area with a mixture of native tree species and saltcedar trees, has more, (rodent) species / types (than the area with\nonly saltcedar trees) / AW ;\nexplanations (max two):\n3 idea of (diversity is lower in the area with only saltcedar trees because) fewer food sources (for rodents) ; ora\n4 saltcedar trees provide less, protection / shelter / nesting sites / niches / AW ; ora\n5 AVP ;\n\n2(d)(i) both error bars correctly plotted ; 1\n\n2(d)(ii) any two from: 2\n1 how close, the calculated / sample, mean is (likely to be) to, the true / actual / real / AW, mean ;\n2 there is overlap in the, SE / error, bars (of the two means) ;\n3 (this indicates that) there is no (statistically) significant difference (between the two means) ;\n\n2(d)(iii) idea that: 1\nthere is no difference between the abundance of the deer mouse in, areas with only saltcedar trees and in areas with a\nmixture of native tree species and saltcedar trees / the two types of woodland ;\n© UCLES 2022 Page 8 of 9", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_52-p07.png", "../answer-assets/9700_m22_ms_52-p08.png" ] }, { "id": "9700-2022-m-52-q03", "question_id": "9700-2022-m-52-q03", "subject": "9700", "year": 2022, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 4, "status": "available", "reason": null, "text": "3 any four from: 4\n1 brine soak / treatment 4, kills, 100% / all, slipper limpets ;\n2 brine soak / treatment 4 and, chilled conditions / 4 °C to 5 °C, kills fewer mussels (than brine soak at 12 °C to 13 °C) ;\n3 repeat brine rinse / treatment 3, and at 12 °C to 13 °C kills all slipper limpets and very few mussels (so could be best) ;\nor\nrepeat brine rinse / treatment 3, and at 4 °C to 5 °C kills nearly all slipper limpets and no mussels (so could be best) ;\n4 appropriate paired data quote ;\n5, 6 ref. to reason for uncertainty ; ;\ne.g. only tested 30 individuals / not enough replicates\nno data on long-term impact\nno results for, small / <30 mm / young, mussels\ndid not test with mixture of slipper limpets and mussels\nidea that conclusion not tested statistically\nidea that there is a cost implication (for the different treatments)\n© UCLES 2022 Page 9 of 9", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2022-March/ms/9700_m22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-feb-march/9700_m22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m22_ms_52-p09.png" ] }, { "id": "9700-2022-mj-41-q01", "question_id": "9700-2022-mj-41-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) Eukarya ; 2\nAnimalia ;\n\n1(a)(ii) any one from: 1\nwarning to predators / to deter predators ;\nAVP ;\n\n1(b) any three from: 3\n1 Ca2+ (stays) in, cytoplasm / sarcoplasm ;\n2 Ca2+, binds / bound, to troponin ;\n3 tropomyosin, shifted / does not cover (myosin) binding sites (on actin) ;\n4 myosin-actin, cross bridges / bonds, exist / remain ;\n5 sarcomere(s) / muscle, contracted / shortened / paralysed ;\n\n1(c) any three from: 3\n1 Ca2+, enters / diffuses into, synaptic knob ;\n2 through (voltage-gated) calcium (ion) channels ;\n3 vesicles containing acetylcholine ;\n4 move to / fuse with, presynaptic membrane ;\n5 exocytosis of acetylcholine ;\n© UCLES 2022 Page 7 of 19", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p07.png" ] }, { "id": "9700-2022-mj-41-q02", "question_id": "9700-2022-mj-41-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 14, "status": "available", "reason": null, "text": "2(a) any four from: 4\nstructure function\n1 thylakoid(s) / granum / grana light dependent reaction / photophosphorylation ;\n2 thylakoid membrane(s) have (named), pigments / photosystems / LHC / electron carriers / ETC /\nATP synthase ;\n3 thylakoid membranes / grana, to absorb (more) light ;\nhave large surface area / are\nmany in number\n4 stroma for light independent reaction /\nCalvin cycle ;\n5 stroma has, (named) enzymes / RuBP / reduced NADP ;\n6 stroma colourless OR so light reaches thylakoids OR\nstroma contains water as a medium for reactions / for photolysis\n7 DNA / ribosomes make (named), chloroplast proteins / proteins for photosynthesis ;\n8 starch grains / lipid droplets store, (named) product of photosynthesis / (chemical) energy ;\n9 envelope compartmentalisation ;\n\n2(b) any three from: 3\n1 light excites electrons in, P700 / PS1 (reaction centre chlorophyll) ;\n2 electrons passed, along carriers / to ETC ;\n3 H+ / protons, pumped into thylakoid, space / lumen ;\n4 H+ / protons, diffuse (back to stroma) through ATP synth(et)ase ;\n5 makes ATP ;\n6 AVP ;\n© UCLES 2022 Page 8 of 19\n\n2(c) any seven from: 7\ndescription\nD1 identify wavelengths for chlorophyll (a) absorption ;\nD2 identify wavelengths for phycoerythrin absorption ;\nD3 identify wavelengths for phycocyanin absorption ;\nD4 chlorophyll (a), has peaks / absorbs mainly, in blue and red ;\nD5 phycoerythrin absorbs in blue and green and yellow ;\nD6 phycocyanin absorbs in (green) yellow and red ;\nexplanation\nE7 red algae / deep water, get(s) green (and yellow) light ;\nE8 chlorophyll (a) absorbs, no / little, green (and yellow) light ;\nE9 phycoerythrin / phycocyanin / accessory pigments, absorbs wavelengths not absorbed by chlorophyll (a) ;\nE10 combined pigments absorb, greater range of / any / all, wavelengths ;\nE11 increases / more / high(er) rate of, light dependent stage / photosynthesis ;\nE12 (so) more / lots of, (named) organic compounds / growth ;\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p08.png", "../answer-assets/9700_s22_ms_41-p09.png" ] }, { "id": "9700-2022-mj-41-q03", "question_id": "9700-2022-mj-41-q03", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "3(a) anabolic / condensation / polymerisation ; 1\n\n3(b) 1 to, phosphorylate / add phosphate to, glucose ; 2\nand any one from:\n2 stops glucose leaving the cell ;\n3 activates glucose / makes glucose less stable ;\n4 to make fructose (1,6) bi(s)phosphate ;\n\n3(c) cytoplasm and mitochondrial matrix ; 1\n© UCLES 2022 Page 9 of 19\n\n3(d) any two from: 2\n1 decarboxylated / loses carbon dioxide ;\n2 dehydrogenated / oxidised / loses H ;\n3 , 2C / acetyl, (group) joins coenzyme A to make acetyl coA ;\n\n3(e) any three from: 3\nmitochondria chloroplasts\n1 oxidative phosphorylation photophosphorylation ;\n2 inner mitochondrial membrane / crista(e) thylakoid membrane ;\n3 reduced NAD / reduced FAD, give e– / H+ photolysis / water / PS1 / chlorophyll,\ngive e– / H+ ;\n4 (H+ ) intermembrane space (H+ ) thylakoid, space / lumen ;\n5 oxygen, final, e– / H+, acceptor NADP final, e– / H+, acceptor ;\n6 (makes) water / H O (makes) reduced NADP ;\n2\n© UCLES 2022 Page 10 of 19", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p09.png", "../answer-assets/9700_s22_ms_41-p10.png" ] }, { "id": "9700-2022-mj-41-q04", "question_id": "9700-2022-mj-41-q04", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "4(a) 5\nstatement genetic engineering gene editing\nusing a plasmid\nIt can produce a transgenic organism.   ;\nIt can modify the characteristics of an organism.   ;\nIt can delete unwanted DNA.  ;\nIt uses an enzyme that cuts DNA.   ;\nIt can use RNA to precisely locate the target gene.  ;\n\n4(b)(i) A ; 1\n\n4(b)(ii) any three from: 3\n1 more food / increase yield / help solve global demand for food ;\n2 improves quality of, fruit / oranges / crop ;\n3 more income for, growers / farmers ;\n4 cheaper / lower cost, fruit / oranges / food (to consumer) ;\n5 spend less on / use less / no need for, (bactericidal) chemicals / pesticides ;\n© UCLES 2022 Page 11 of 19", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p11.png" ] }, { "id": "9700-2022-mj-41-q05", "question_id": "9700-2022-mj-41-q05", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 14, "status": "available", "reason": null, "text": "5(a) any four from: 4\n1 geographical isolation / allopatric (sub)speciation ;\n2 little / no, (inter)breeding / gene flow, between populations ;\n3 different, selection / selective, pressures (on each population) ;\n4 different mutations (in each population) ;\n5 adaptation to, environment / habitat / climate / food / vegetation ;\n6 gives, morphological / ecological / behavioural, differences ;\n\n5(b)(i) any two from: 2\n1 natural / selection ;\n2 dark, colour / fur, selected for / adaptive / good, in woods / warm / shade ;\n3 camouflage / right colour, protects against, (named) predators ;\n\n5(b)(ii) any two from: 2\n1 genetic drift / not natural selection ;\n2 as small size in north not, adaptive / beneficial ;\n3 (small) lose heat faster / harder to keep warm ;\n4 smaller fat reserves not good with unstable food supply ;\n5 less food in north reduces, growth / size ;\n6 AVP ;\n\n5(c) any three from: 3\n1 (hybrid populations have) more, genetic variation / alleles ;\n2 genes / mutations / alleles, from both (sub)species ;\n3 more potential to adapt / can adapt better (in future) ;\n4 genes / alleles, for migration may let some find new habitats ;\n5 have, genes / alleles, for, warm and cold / different temperatures ;\n© UCLES 2022 Page 12 of 19\n\n5(d) any three from: 3\n1 obtain, blood / tissue / DNA ;\n2 (test) both (sub)species / migratory and non-migratory ;\n3 use PCR to amplify DNA ;\n4 use, (gel) electrophoresis / DNA profiling / DNA fingerprinting, and EITHER compare results OR to see genetic,\ndifferences / changes ;\n5 sequence DNA and, count / identify, differences / changes ;\n6 check / test, for correlation between, DNA / genetic profiles / alleles / markers, and migratory behaviour ;\n7 use, databases / bioinformatics, to find, name / role of, genes / sequences (that, differ / are associated with migration) ;\n8 AVP ;\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p12.png", "../answer-assets/9700_s22_ms_41-p13.png" ] }, { "id": "9700-2022-mj-41-q06", "question_id": "9700-2022-mj-41-q06", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 10, "status": "available", "reason": null, "text": "6(a) homeostasis / negative feedback ; 1\n\n6(b)(i) blood(stream) / circulation ; 1\n\n6(b)(ii) A – adenyl,(-yl) / (-ate), cyclase ; 2\nB – cyclic AMP / cAMP ;\n\n6(b)(iii) amplifies signal / expands message ; 1\n\n6(b)(iv) break down glycogen / glycogen  glucose / glycogenolysis ; 1\n\n6(c) any four from: 4\n1 blood on, pad / strip, inserted into, biosensor / glucometer ;\n2 glucose oxidase ;\n3 (glucose)  gluconic acid and hydrogen peroxide ;\n4 (electric) current / flow of electrons / voltage ;\n5 (current) proportional to glucose, quantity / concentration ;\n6 digital / numerical, reading (on screen) ;\n© UCLES 2022 Page 13 of 19", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p13.png" ] }, { "id": "9700-2022-mj-41-q07", "question_id": "9700-2022-mj-41-q07", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "7(a) gene 2\nlength of DNA coding for a polypeptide ;\nallele\nalternative / different, form / version, of a gene ;\n\n7(b) parents phenotypes red eyes apricot eyes 3\nparents genotypes CRCH CACW\ngametes ( CR CH CA CW )\noffspring genotypes CRCA CRCW CHCA CHCW ;\noffspring phenotypes red eyes (red eyes) apricot eyes honey eyes ;\nratio 2 : 1 : 1 ;\n\n7(c) 1 cross with, white-eyed fly / CWCW ; 3\nany two from:\n2 if all red-eyed then CRCR ;\n3 if (some red-eyed and) some apricot-eyed then CRCA ;\n4 if (some red-eyed and) some honey-eyed then CRCH ;\n5 if (some red-eyed and) some white-eyed then CRCW ;\n© UCLES 2022 Page 14 of 19", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p14.png" ] }, { "id": "9700-2022-mj-41-q08", "question_id": "9700-2022-mj-41-q08", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "8(a)(i) any three from: 3\n1 habitat loss ;\n2 for, agriculture / building / roads / forestry / mines / development ;\n3 hunting / fishing ;\n4 collecting plants ;\n5 humans aid spread of (animal / plant) disease ;\n6 humans aid spread of, alien / invasive / competing, species ;\n7 (named) pollution / pesticides ;\n\n8(a)(ii) 290007000 290007000 22000 2\n1 or ;\n20001950 50 50\n2 440 ;\n© UCLES 2022 Page 15 of 19\n\n8(b) any seven from: 7\n1 (named) food ;\n2 (named) medicines ;\n3 wood / fibres / paper / rubber ;\n4 genetic diversity for future use ;\n5 science / technology / research ;\n6 education ;\n7 aesthetic / wellbeing ;\n8 (eco)tourism / attract visitors ;\n9 ethical / moral / stewardship ;\n10 local cultural significance ;\n11 maintain / protect / stability of, food chains / food webs ;\n12 pollination / ecosystem services ;\n13 protect against, soil erosion / coastal erosion / flooding ;\n14 soil formation ;\n15 (named) mineral, cycles / recycling OR ref. to stage in cycle of named element ;\n16 climate stability ;\n© UCLES 2022 Page 16 of 19", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p15.png", "../answer-assets/9700_s22_ms_41-p16.png" ] }, { "id": "9700-2022-mj-41-q09", "question_id": "9700-2022-mj-41-q09", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 6, "status": "available", "reason": null, "text": "9(a) 2\nletter feature\nB location of Calvin cycle ;\nD made of cellulose ;\n\n9(b) any four from: 4\n1 H+ pumped, out of guard cell / into cell wall of guard cell ;\n2 inside of cell becomes (relatively) negatively charged ;\n3 K+ enters cell by facilitated diffusion ;\n4 water potential of cell decreases ;\n5 water enters cell by osmosis ;\n6 cell, expands / increases in volume / becomes turgid ;\n7 stoma opens due to thick inner wall ;\n© UCLES 2022 Page 17 of 19", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p17.png" ] }, { "id": "9700-2022-mj-41-q10", "question_id": "9700-2022-mj-41-q10", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "10(a) 3\nmotor sensory\n1 transmits impulses from CNS to effector transmits impulses from, receptors / (named) sense\nand ;\norgans, to CNS\nplus two from:\nmotor sensory\n2 cell body at end of, neurone / axon cell body, in middle of / part-way along, neurone OR cell\nand ;\nbody not at end of, neurone / axon\n3 cell body in, CNS / brain / spinal cord and cell body in (dorsal root) ganglion ;\n4 long axon OR short axon OR\nand ;\naxon axon and dendron\n5 dendrites attached to cell body and dendrites attached to dendron ;\n\n10(b) any three from: 3\n1 no myelin slow and myelin fast(er) / myelin increases speed ;\n2 no myelin = 0.5–2 m s–1 and with myelin > 5 / up to 120 m s–1 ;\n3 as axon diameter increases speed increases ;\n4 diameter (+ units once) and speed (+ units once) for two neurones ;\n© UCLES 2022 Page 18 of 19\n\n10(c) any three from: 3\nA – any one reason from:\n1 Na+ / sodium, channels already open OR\nNa+ has already entered neurone OR\nno more Na+ channels to open OR\nless Na+ outside to diffuse in OR\nless steep Na+ concentration gradient ;\nB – any one reason from:\n2 sodium channels are, inactive / unresponsive OR\npotassium channels are open OR\nmembrane is, impermeable / less permeable, to Na+ OR\nmembrane is more permeable to K+ ;\nC – any one reason from:\n3 harder to reach threshold OR\npotassium channels are (still) open OR\nsodium-potassium pumps need to restore the resting potential ;\n4 hyperpolarisation at C ;\n© UCLES 2022 Page 19 of 19", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_41-p18.png", "../answer-assets/9700_s22_ms_41-p19.png" ] }, { "id": "9700-2022-mj-42-q01", "question_id": "9700-2022-mj-42-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "1(a)(i) DOPA / dopaquinone / melanin ; 1\n\n1(a)(ii) cyclic AMP / cAMP ; A calcium ions 1\n\n1(a)(iii) any two from: 2\n1 albino / albinism ;\n2 no pigment or melanin in skin / pale skin\nor\nwhite hair ; Ignore fair, skin / hair\n3 red / pink, eyes / irises ; A blue\n4 poor vision / described\nor eyes sensitive to light\nor jerky eye movements ; Ignore blindness\n\n1(b) symbols ; e.g. B allele for black fur 4\nb allele for (light) brown fur\nparental genotypes Bb x Bb\n;\ngametes B b B b\noffspring genotypes BB Bb (Bb) bb ;\noffspring phenotypes black black (black) (light) brown ;\naccept gametes mark from a Punnett square\n© UCLES 2022 Page 5 of 22", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p05.png" ] }, { "id": "9700-2022-mj-42-q02", "question_id": "9700-2022-mj-42-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 15, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\n1 ref. to light energy / photons ;\n2 for, light-dependent stage / photophosphorylation / photolysis / photoexcitation / photoactivation ;\n3 to make, reduced NADP / ATP ;\n4 to open stomata (for CO to enter) ;\n2\n\n2(a)(ii) correctly showing that TP reduces to a plateau below GP ; 2\ncorrectly showing that RuBP increases to a plateau ;\n© UCLES 2022 Page 6 of 22\n\n2(a)(iii) 1. decrease in / no, CO , diffusing / moving, to, 3\n2\nair spaces / palisade cells / mesophyll cells / chloroplasts / stroma ;\nany two from:\n2 stress response / AW ;\n3 ref. to abscisic acid / ABA ;\n4 ref. to action of Ca2+ as a second messenger ;\n5 stomata close ;\n\n2(b)(i) 2820.5 7.5 2\n 100 or  100 ; A 20.4 or 20.6\n20.5 20.5\nA 37.3 or 35.9\nanswer to 1 decimal place\n36.6 (%) ;\napply ecf\n© UCLES 2022 Page 7 of 22\n\n2(b)(ii) any four from: 4\nno mention of increased or more – ecf and max 3\n1 Sox4 plants have an extra copy of SBPase gene ;\n2 (overall) increased, expression / transcription, of SBPase gene\n(so more SBPase) ;\n3 increased (rate of) / more, regeneration / production, of RuBP ;\n4 (so) increased / more,\ncarbon fixation / Calvin cycles / light independent reaction / TP / GP ;\n5 more, glucose / sucrose, for respiration / ATP production\nor\nmore, starch / lipid, for storage\nor\nmore cellulose for cell walls ;\n6 more, amino acids / proteins, for growth ;\n7 more, cell division / cell elongation / mitosis ;\n8 AVP ; e.g.(new) SBPase / SBPase gene, more efficient\n\n2(b)(iii) nitrogen needed to produce: 2\nnucleotides for,\ntranscription (of SBPase gene) / expression (of SBPase gene) / mRNA production ;\namino acids for, protein synthesis / SBPase production / enzyme production ;\n© UCLES 2022 Page 8 of 22", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p06.png", "../answer-assets/9700_s22_ms_42-p07.png", "../answer-assets/9700_s22_ms_42-p08.png" ] }, { "id": "9700-2022-mj-42-q03", "question_id": "9700-2022-mj-42-q03", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "3(a) any four from: 4\naccept ora\n1 pyruvate converted to, acetyl group / 2C group / acetyl CoA (in link reaction) ;\n2 NAD needed (in link reaction) ;\n3 (where) NAD becomes reduced ;\n4 reduced NAD goes to ETC ;\n5 ETC / oxidative phosphorylation, works if oxygen is present\nor\noxygen is the final electron acceptor ;\n6 (so) reduced NAD is oxidised / NAD is regenerated ;\n\n3(b) any five from: 5\n1 glycolysis ;\n2 phosphorylation of glucose ;\n3 splitting of fructose (1,6) bi(s)phosphate / AW ;\n4 (into) two, triose phosphate / TP ;\n5 (TP) oxidised / dehydrogenated, to pyruvate ;\n6 net 2 ATP / 4 ATP, produced ;\n7 (2) reduced NAD produced ;\n© UCLES 2022 Page 9 of 22", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p09.png" ] }, { "id": "9700-2022-mj-42-q04", "question_id": "9700-2022-mj-42-q04", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "4(a) 5\nstatement genetic engineering gene editing\nusing a plasmid\nIt may cause the   ;\norganism to produce a\ndifferent protein.\nIt may cause a single  ;\nbase pair in a gene to\nbe changed.\nThe success of the  ;\ntechnique can be\nevaluated using marker\ngenes.\nIt may use the CRISPR  ;\nsystem.\nIt uses DNA ligase.  ;\n\n4(b)(i) C ; 1\n© UCLES 2022 Page 10 of 22\n\n4(b)(ii) any three from: 3\n1 increased / high, (crop) yield ;\n2 idea of less food shortages / more food production / helps solve global demand for food ;\n3 less need to remove weeds (by hand) ;\n4 more income for, growers / farmers\nor\nref. to economic benefit for, country / region ;\n5 cheaper / lower cost, to buy ;\n6 AVP ; e.g. less need for deforestation of other land\n© UCLES 2022 Page 11 of 22", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p10.png", "../answer-assets/9700_s22_ms_42-p11.png" ] }, { "id": "9700-2022-mj-42-q05", "question_id": "9700-2022-mj-42-q05", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 14, "status": "available", "reason": null, "text": "5(a) any four from: 4\n1 geographical isolation / barrier qualified ; Ignore separation\n2 no, interbreeding / gene flow (between European and American populations) ;\nIgnore reproductive isolation here (needs to be late on in process)\n3 different, environmental (conditions) / selection pressures ;\n4 random / different, mutations ;\n5 different, alleles selected for / gene pool / changes in allele frequency ;\n6 populations have different, morphological / physiological / behavioural, features ;\n7 after, a long time / many generations, reproductive isolation occurs / cannot interbreed to produce fertile offspring ;\n8 allopatric (speciation) ;\n© UCLES 2022 Page 12 of 22\n\n5(b) any three from: 3\n1 not possible / difficult, to come to a (reliable) conclusion ; A AW\n2 small difference in height / heights are similar\n(so natural selection not more important than genetic drift) ;\n3 taller / lighter, bison could be an advantage in reaching higher vegetation\n(so natural selection may be important) ;\n4 difference in mass, may not be due to genetic factors /\nmay be due to nutrient value of diet /\nmay be due to quantity of food,\n(so natural selection may not be important) ;\n5 genetic drift (in ancestral population) may have led to,\nEuropean bison being, taller / lighter\nor\nAmerican bison being, shorter / heavier ;\n\n5(c) 1 European bison has a, close / recent / common, ancestor with that of, cattle / Bos 3\nor\nEuropean bison is more closely related to, cattle / Bos, (than to American bison) ;\n2 European bison may have interbred with, cattle / Bos ;\n3 mitochondria are inherited from, mother / female ;\n© UCLES 2022 Page 13 of 22\n\n5(d) any four from: 4\n1 obtain / use, blood / cells / tissue / DNA ;\n2 from, both species / cattle and European bison ;\n3 use PCR to, replicate / amplify, DNA ;\n4 use, electrophoresis (described) / DNA profiling / DNA fingerprinting,\nto see genetic differences / compare the banding (patterns) ;\n5 sequence DNA and, count / identify, (percentage) difference / similarity\nor\nsequence DNA and compare the, nucleotide / base, sequence ;\n6 use, genome / DNA, microarray ; R for gene expression\n7 ref. to bioinformatics / database / (computer) software ;\n8 similarity indicates, close relationship / more recent split ;\n9 if they can breed to produce (viable) offspring (they are closely related) ;\n© UCLES 2022 Page 14 of 22", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p12.png", "../answer-assets/9700_s22_ms_42-p13.png", "../answer-assets/9700_s22_ms_42-p14.png" ] }, { "id": "9700-2022-mj-42-q06", "question_id": "9700-2022-mj-42-q06", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "6(a) G – embryo to aleurone layer ; 2\nA – aleurone layer to endosperm ;\n\n6(b) any three from: 3\n1 hydrolyses / breaks down / digests / converts, starch / amylose ;\n2 in endosperm ;\n3 to, maltose / glucose ;\n4 (glucose) used by embryo ;\n5 (glucose used) for, respiration / growth ;\n© UCLES 2022 Page 15 of 22\n\n6(c) any four from: 4\naccept distilled water for A, 500mg dm-3 for B and 1000mg dm-3 for C.\n1 seeds of B and C germinated before seeds of A\nor\nseeds soaked in gibberellin germinated before\nseeds soaked in distilled water ; ora\n2 rate of (increase in percentage) germination was, highest in C\nor\nhigher in C than, B / A\nor\nhigher as the concentration of\ngibberellin increases ; ora\n3 final / day 10 / maximum (percentage) germination was, highest in C\nor\nhigher in C than, B / A\nor\nhigher as the concentration of\ngibberellin increases ; ora\n4 data quote between two groups ;\nmp1 – A by day 6 and B and C by day 2\nmp1 – A germinates four days after B and C ora\nmp2 – A – 2.2 B – 5.2 C – 9.2, percentage germination day-1\nmp3 – A – 22% B – 52% C – 92%\nmp3 – A to C = 70% more, A to B = 30% more, B to C = 40% more\n5 percentage germination in C levels off after 9 days ;\n6 AVP ; e.g. no seeds germinate by day 1\n© UCLES 2022 Page 16 of 22", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p15.png", "../answer-assets/9700_s22_ms_42-p16.png" ] }, { "id": "9700-2022-mj-42-q07", "question_id": "9700-2022-mj-42-q07", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "7(a) RNA polymerase attached to promoter ; 2\nrepressor detached from operator ;\n\n7(b)(i) structural (gene) ; 1\n\n7(b)(ii) lactose permease ; A beta-galactoside permease 2\nmovement / transport, of lactose into cell\nor\nmakes (cell surface) membrane (more) permeable to lactose ;\n\n7(c) 1 population increases, then levels off, increases, then levels off / AW ; 4\nany three from:\n2 (first increase) glucose, metabolised / respiration ;\n3 (first levelling off) glucose has run out ;\n4 (first levelling off) lactose, hydrolysed / broken down, into, glucose / galactose ;\n5 (second increase) glucose / galactose, metabolised / respired ;\n6 (second levelling off) lactose / glucose / galactose, has run out ;\n7 AVP ; e.g. idea of time delay\n(for, lactose permease / beta galactosidase, to work)\n© UCLES 2022 Page 17 of 22", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p17.png" ] }, { "id": "9700-2022-mj-42-q08", "question_id": "9700-2022-mj-42-q08", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "8(a) microvilli ; A brush border 1\n\n8(b) no movement of, chemicals / substances / ions, between the, 1\nchemoreceptor / cells / (cells) A ;\nIgnore food\nA named dissolved substance\n© UCLES 2022 Page 18 of 22\n\n8(c) any seven from: 7\n1. Na+ ions enter, (chemo)receptor cell / A, through,\nmicrovilli / Y / channel (proteins) ;\n2 cell surface membrane depolarised ;\n3 receptor potential ;\n4 ref. to threshold ;\n5 (voltage-gated) Ca2+ / calcium, channels open ;\n6 Ca2+ ions enter, cytoplasm / cell / A ; A presynaptic knob\n7 vesicles (of neurotransmitter), move towards / fuse with,\ncell surface membrane / presynaptic membrane ;\n8 exocytosis (described) / secretion, of (named) neurotransmitter ;\n9 neurotransmitter binds to receptor on,\npostsynaptic / (sensory) neurone / B, membrane ;\n10 Na+ / sodium, channels open\nor\nNa+ enter (sensory) neurone / B ;\n11 postsynaptic membrane / (sensory) neurone membrane, depolarised ;\n12 ref. to threshold ;\nallow either mp4 or mp12\n© UCLES 2022 Page 19 of 22", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p18.png", "../answer-assets/9700_s22_ms_42-p19.png" ] }, { "id": "9700-2022-mj-42-q09", "question_id": "9700-2022-mj-42-q09", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 7, "status": "available", "reason": null, "text": "9(a) to generate a high, blood pressure / hydrostatic pressure ; 2\nIgnore to increase the blood pressure\nto force, plasma / fluid / water,\nthrough basement membrane / into the Bowman’s capsule / into lumen ;\nR osmosis / diffuse\nIgnore named substance e.g. glucose\n\n9(b)(i) A – basement membrane ; 2\nB – podocyte ;\n\n9(b)(ii) any three from: 3\nA basement membrane\n1 acts as a, filter / filtration barrier ;\n2 only, named molecules / ions / molecules less than 68 000–70 000 (R)MM,\ncan pass through\nor\nred blood cells / large proteins, cannot pass through ;\nB podocyte\n3 has, gaps / slits / projections / pores ;\n4 allows, fluid / water / filtrate, to pass into the, lumen / Bowman’s capsule ;\n5 produces, A / basement membrane ;\n© UCLES 2022 Page 20 of 22", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p20.png" ] }, { "id": "9700-2022-mj-42-q10", "question_id": "9700-2022-mj-42-q10", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 11, "status": "available", "reason": null, "text": "10(a) any three from: 3\n1 marking, not harmful (described) / cannot be removed (described) ;\n2 constant population size ;\n3 no, births / deaths (described)\nor\nno, immigration / emigration / migration ;\n4 (sufficient time for) marked individuals to mix with rest of population ;\n5 (penguins are) mobile ;\n\n10(b) any three from: 3\n1 loss of habitat / example ;\n2 climate change ;\n3 predation ;\n4 competition for, food / resources / breeding sites / example ;\n5 new disease ;\n6 pollution / example ;\n7 numbers get so low that population can’t recover / AW ;\n\n10(c) 13 000 / 1.3  104 ; 1\n© UCLES 2022 Page 21 of 22\n\n10(d) any four from: 4\n1 multicellular ;\n2 eukaryote / eukaryotic / (cells) contain a nucleus ;\n3 specialised cells / tissues / organs ;\n4 heterotrophic (nutrition) / described ;\n5 nervous system ;\n6 cilia / flagella ;\n7 mobile / motile ;\n© UCLES 2022 Page 22 of 22", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_42-p21.png", "../answer-assets/9700_s22_ms_42-p22.png" ] }, { "id": "9700-2022-mj-43-q01", "question_id": "9700-2022-mj-43-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) 1 loop of Henle ; 2\n2 collecting duct ;\n\n1(a)(ii) antidiuretic hormone / ADH ; A vasopressin 1\n\n1(a)(iii) 1 as the RMT increases the concentration of urine increases ; A positive correlation 4\n2 two pairs of comparative figures ;\nRMT urine conc.\nbeaver 1.4 0.90\nkangaroo rat 8.6 10.50\nany three from:\nkangaroo rat\n3 little water available / AW ; Ignore desert Ignore rivers & lakes for ora\n4 loop of Henle / collecting duct, is longer ;\n5 (so) more reabsorption of water occurs ; Ignore retaining more water\n6 (so) urine (of kangaroo rat) more concentrated / small volume of urine ;\nallow ora for beaver\n© UCLES 2022 Page 5 of 23\n\n1(b) any two from: 2\n1 ref. to metabolic water / water from respiration ;\n2 it obtains water through the (named) food it eats ;\n3 AVP ; e.g. behavioural response / no or less sweating\n© UCLES 2022 Page 6 of 23", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p05.png", "../answer-assets/9700_s22_ms_43-p06.png" ] }, { "id": "9700-2022-mj-43-q02", "question_id": "9700-2022-mj-43-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) any four from: 4\nsimilarities\n1 photoactivation of chlorophyll / AW, occurs in both ; A excite electrons (for AW)\n2 ETC involved in both ;\n3 ATP produced in both ;\ndifferences\ncyclic non-cyclic\n4 only PSI PSI and PSII both involved ;\n5 no, reduced NADP / oxygen, produced reduced NADP / oxygen, produced ;\n6 no photolysis photolysis ;\nor or\nno oxygen-evolving oxygen-evolving\ncomplex involved complex involved\n7 electrons emitted from PSI electrons emitted from PSII are replaced by water ;\nreturned to PSI or\nor water is source of electrons\nPS1 is source of electrons\n© UCLES 2022 Page 7 of 23\n\n2(a)(ii) any two from: 2\n1 no ATP and reduced NADP made ;\n2 no, GP / TP, made\nor\nno, Calvin cycle / light-independent reaction ;\n3 no regeneration of RuBP ;\n\n2(b)(i) any four from: 4\n1 as the CO concentration increases, the rate of fixation of CO increases ;\n2 2\n2 (as) CO concentration is the limiting factor ;\n2\n3 as the CO concentration increases, the rate of fixation of CO , remains the same / plateaus ;\n2 2\n4 (as) CO concentration is no longer the limiting factor\n2\nor\ntemperature / light intensity / RuBP regeneration, is the limiting factor ;\n5 paired data quote with units to support, mp1 / mp3 ;\nCO concentration / mg m–3 CO fixation rate / µmol CO m–2 s–1\n2 2 2\nmp1 50 ±10 1 ±0.25\n1200–1280 42 A 41.75\nmp3 from 1200–1910 42 A 41.75\n© UCLES 2022 Page 8 of 23\n\n2(b)(ii) any three from: 3\nassume Sox4 – accept ora for wild\n1 the rate of fixation of CO is higher in Sox4 compared to wild type\n2\nor\nSox4 reaches a higher (maximum) rate of CO fixation ;\n2\n2 (wild type) 42 vs (Sox4) 47 mol CO m–2s–1 ;\n2\n3 (Sox4 has) more SBPase\nor\nthere is a faster (rate of) regeneration of RuBP\nor\n(new) SBPase more effective ;\n4 more RuBP to react with, CO / rubisco ;\n2\n© UCLES 2022 Page 9 of 23", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p07.png", "../answer-assets/9700_s22_ms_43-p08.png", "../answer-assets/9700_s22_ms_43-p09.png" ] }, { "id": "9700-2022-mj-43-q03", "question_id": "9700-2022-mj-43-q03", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "3(a) any two from: 2\nsubstrate-linked (phosphorylation) ; A substrate level phosphorylation\nchemiosmosis / oxidative (phosphorylation) ;\n\n3(b) any six from: 6\n1 hydrogen / electron, carriers ; R hydrogen ions / hydrogen molecules\n2 in glycolysis NAD becomes reduced ;\n3 (so that) triose phosphate becomes, oxidised / dehydrogenated ;\n4 in the link reaction NAD becomes reduced ;\n5 (so that) pyruvate becomes, oxidised / dehydrogenated\nor\nfor production of acetyl coenzyme A ;\n6 in the Krebs cycle both NAD and FAD become reduced ;\n7 to regenerate oxaloacetate ;\n8 (deliver, hydrogen / H+ and e–), to inner mitochondrial membrane / to cristae / to ETC / for oxidative phosphorylation / for\nchemiosmosis ;\n9 ref. to ATP production ;\n10 ref. to recycling of, NAD / FAD ;\n© UCLES 2022 Page 10 of 23\n\n3(c) any two from: 2\n1 ref. to increase / decrease / control, of (rate of the) link reaction ;\n2 allows build-up of acetyl CoA to be used in the Krebs cycle ;\n3 enzyme becomes active again when, coenzyme A increases / ratio falls ;\n4 allows more coenzyme A, to enter / return to, the link reaction ;\nA not enough CoA to enter the link reaction ora\n5 AVP ; e.g. end product inhibition\n© UCLES 2022 Page 11 of 23", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p10.png", "../answer-assets/9700_s22_ms_43-p11.png" ] }, { "id": "9700-2022-mj-43-q04", "question_id": "9700-2022-mj-43-q04", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "4(a) 5\nstatement genetic engineering gene editing\nusing a plasmid\nIt can add a new phenotypic characteristic to an organism.   ;\nIt can change an A-T base pair to C-G.  ;\nIt can inactivate a desired selected gene in an organism.  ;\nIt may change DNA in a way that cannot be told apart from a\n ;\nnatural mutation.\nIt requires a DNA donor and a recipient.  ;\n\n4(b)(i) A ; 1\n\n4(b)(ii) any three from: 3\n1 less food waste ; A increases quality of food\n2 idea of less food shortages / more food production / helps solve global demand for food ;\n3 more income for, growers / farmers\nor\nref. economic benefit for, country / region ;\n4 crop can be grown, when there is a water shortage / in poor quality soil / in harsh environment ;\n© UCLES 2022 Page 12 of 23", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p12.png" ] }, { "id": "9700-2022-mj-43-q05", "question_id": "9700-2022-mj-43-q05", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 14, "status": "available", "reason": null, "text": "5(a) any four from: 4\n1 (partial) geographical, isolation / separation / barrier;\n2 little / no, interbreeding / gene flow (between puma populations) ;\n3 different, environmental (conditions) / selection pressures ;\n4 e.g. climate / vegetation / habitat / available prey ;\n5 random / different, mutations ;\n6 different, alleles selected for / gene pool / changes in allele frequency ;\n7 allopatric (sub speciation) ;\n\n5(b) any three from: 3\n1 obtain, blood / cells / tissue / DNA ;\n2 from two (or more) individuals, at different locations / across range / from North and South America / from the different\nsubspecies ;\n3 use PCR to, replicate / amplify DNA ;\n4 use, gel electrophoresis / DNA profiling / DNA fingerprinting ;\n5 sequencing of DNA ;\n6 use, genome / DNA, microarray ; R for gene expression\n7 ref. to bioinformatics / database / (computer) software ;\n8 compare similarity (of different sub species);\n© UCLES 2022 Page 13 of 23\n\n5(c)(i) any two from: 2\ndiscontinuous (no mark) because:\n1 feature either present or absent ;\n2 categoric ;\n3 no range / no intermediates\nor\nqualitative data\nor\ndoes not show a normal distribution curve;\n\n5(c)(ii) any three from: 3\n1 these features are controlled by, genes / alleles ;\n2 ref. to genetic drift ;\n3 (population went through a) bottleneck ;\n4 low / reduced, number of alleles / genetic diversity / genetic variation / genetic polymorphism (in population) ;\nA some alleles lost\n5 inbreeding ;\n6 low / reduced, heterozygosity or high / increased, homozygosity ;\n7 rare / deleterious, recessive alleles show their effects (as homozygous) ;\n8 AVP ; e.g. number of breeding males reduced even more as some have, non-functional / undescended, testes\n© UCLES 2022 Page 14 of 23\n\n5(c)(iii) any two from: 2\n1 Texas is closest to Florida ; ora A / B, distant / far away\n2 (Texas and Florida pumas) are most closely-related / most genetically similar share most recent common ancestor ;\nora A / B\n3 Texas and Florida, climates / habitats / environment, are similar ; ora for A / B\n4 AVP ; e.g. Texas has too many pumas", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p13.png", "../answer-assets/9700_s22_ms_43-p14.png", "../answer-assets/9700_s22_ms_43-p15.png" ] }, { "id": "9700-2022-mj-43-q06", "question_id": "9700-2022-mj-43-q06", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "6(a) 1 microvilli ; A brush border I papillae 3\n2 increase surface area ;\n3 (so), more (Na+) channels / more Na+ enter ;\n© UCLES 2022 Page 15 of 23\n\n6(b) any six from: 6\n1 vesicles of neurotransmitter are stimulated to move ;\n2 vesicles fuse with, cell surface membrane / presynaptic membrane ;\n3 exocytosis (described) / secretion, of (named) neurotransmitter ;\n4 neurotransmitter diffuses across, synapse / (synaptic) cleft / gap between cells A and B ;\n5 neurotransmitter binds to receptors ;\n6 on, cell surface / postsynaptic / (sensory) neurone / B, membrane ;\n7 Na+ / sodium, channels open ;\n8 Na+ enter, (sensory) neurone / B ;\n9 postsynaptic membrane / (sensory) neurone membrane, depolarised ;\n10 ref. to threshold ;\n© UCLES 2022 Page 16 of 23", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p15.png", "../answer-assets/9700_s22_ms_43-p16.png" ] }, { "id": "9700-2022-mj-43-q07", "question_id": "9700-2022-mj-43-q07", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "7(a) gene – a length of DNA / a sequence of DNA nucleotides, that codes for a particular, protein / polypeptide ; 2\nlocus – the position of a, gene / allele, on a chromosome ;\n\n7(b) parent genotype ( AaBb  AaBb ) 6\nparent phenotype brown (brown) ;\ngametes AB Ab aB ab  ( AB Ab aB ab ) ;\nAB Ab aB ab\nAB AABB AABb AaBB AaBb\nAb AABb AAbb AaBb Aabb\naB AaBB AaBb aaBB aaBb\nab AaBb Aabb aaBb aabb ;;\noffspring phenotypes linked to genotypes ;\nratio – 9 brown : 3 black : 4 white ;\n© UCLES 2022 Page 17 of 23\n\n7(c) any three from: 3\n1 (base), substitution / deletion / insertion\nor\nframe shift ;\n2 ref. to change in, primary / secondary / tertiary, structure (of polypeptide / protein)\nor\nchange in, 3D / active site, shape ;\n3 ref. to stop codon ;\n4 (so) no / inactive, tyrosinase produced ;\n5 tyrosine not converted to, DOPA / dopaquinone ;\n6 melanin not formed ;\n© UCLES 2022 Page 18 of 23", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p17.png", "../answer-assets/9700_s22_ms_43-p18.png" ] }, { "id": "9700-2022-mj-43-q08", "question_id": "9700-2022-mj-43-q08", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "8(a) any two from: 2\n1 loss of habitat / described ;\n2 climate change / global warming ;\n3 predation ; I hunting\n4 competition for, food / resources / breeding sites / example ; A not enough food\n5 new disease ;\n6 numbers get so low that population can’t recover / AW ;\n\n8(b) any three from: 3\n1 trade ban (if species is in danger of extinction) ;\n2 if species is not (yet) at risk of extinction permit required ;\n3 ref. to border controls / checks ; A fines / punishment if caught\n4 (provide countries with) lists of species that are, rare / endangered ;\n5 encourages governments, to join CITES / to abide by CITES regulations ;\n6 AVP ; e.g. every few years they have a conference with their members\n© UCLES 2022 Page 19 of 23\n\n8(c) any four from: 4\n1 captive breeding / description ;\n2 assisted reproduction / example ;\n3 reintroduce into the wild ;\n4 medical care ;\n5 education / public awareness ;\n6 research ;\n7 projects in the field ;\n8 ref. to maintaining genetic databases, to avoid inbreeding\nor\nworking with other zoos ;\n© UCLES 2022 Page 20 of 23", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p19.png", "../answer-assets/9700_s22_ms_43-p20.png" ] }, { "id": "9700-2022-mj-43-q09", "question_id": "9700-2022-mj-43-q09", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 6, "status": "available", "reason": null, "text": "9(a) A – axon / axoplasm ; 2\nB – Schwann cell nucleus ;\n\n9(b) 1 myelinated has faster speed (of transmission of action potential) ; 4\nplus\nany three from:\n2 (myelinated) Na+ channels only occur at nodes of Ranvier\nor\n(non-myelinated) Na+ channels occur along length of neurone ;\n3 (myelinated) depolarisation only occurs at nodes\nor\n(non-myelinated) depolarisation occurs along length of neurone ;\n4 (myelinated) long local circuits\nor\n(non-myelinated) short local circuits ;\n5 (myelinated) saltatory conduction / described ;\n6 AVP ; e.g. 100 ms–1 v 2 ms–1\n© UCLES 2022 Page 21 of 23", "source_pages": [ 21 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p21.png" ] }, { "id": "9700-2022-mj-43-q10", "question_id": "9700-2022-mj-43-q10", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 10, "status": "available", "reason": null, "text": "10(a)(i) any three from: 3\n1 as the, blood glucose / glucose concentration, increases the, blood insulin / insulin concentration, increases ; A positive\ncorrelation\n2 data quote with unit ;\ndata quote for mp1\ntime of day blood glucose conc / mmol dm–3 time of day blood insulin conc / pmol dm–3\n±1.5 min ±0.025 ±1.5 min ±1\n07.00 4.3 07.15 30\n08.00 6.2 08.00 280\ndata quote for mp5\ntime of day blood glucose conc / mmol dm–3 time of day blood insulin conc / pmol dm–3\n±1.5 min ±0.025 ±1.5 min ±1\n08.00 6.2 08.00 280\n09.00 4.45 09.00 120\n3 increase in, blood glucose / glucose concentration, causes release of insulin (from pancreas) ; ora\n4 insulin stimulates the conversion of glucose to glycogen / glycogenesis\nor\ninsulin increases permeability (of liver / muscle) cells to glucose / AW ;\n5 insulin causes, blood glucose / glucose concentration, to return back to set point ;\n6 ref. to negative feedback ;\n© UCLES 2022 Page 22 of 23\n\n10(a)(ii) any three from: 3\nmax 2 if only glucose or insulin curve mentioned\n1 ref. to delay before both graphs increase / AW ;\n2 peaks for both would be lower ;\n3 both curves would take longer to decrease ;\n4 time is needed for starch to be, broken down / converted (to glucose) ;\n5 to glucose ;\n\n10(b) any four from: 4\n1 ref. to adenylyl cyclase ;\n2 formation of, cyclic AMP / cAMP ;\n3 cAMP acts as a second messenger ;\n4 activation of (protein) kinase ;\n5 enzyme cascade ;\n6 amplification of signal ;\n7 glycogenolysis / gluconeogenesis / described ;\n8 glucose released into blood ;\n© UCLES 2022 Page 23 of 23", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_43-p22.png", "../answer-assets/9700_s22_ms_43-p23.png" ] }, { "id": "9700-2022-mj-51-q01", "question_id": "9700-2022-mj-51-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 16, "status": "available", "reason": null, "text": "1(a)(i) independent variable: 2\n(type of) habitat / described ;\ndependent variable:\ndensity / number / AW, of stomata ;\n\n1(a)(ii) Radius / diameter (of field of view / image / circle / Fig 1.2) ; 2\nnumber of stomata ;\n\n1(a)(iii) 2 marks for density range: 2\n0.014–0.019 ; ;\nif outside this range one mark for:\nstomatal number:\n61 (full) – 69 (all) ;\narea:\n4069 – 4301 ;\n© UCLES 2022 Page 6 of 10\n\n1(a)(iv) any six from: 6\n1 ref. to method of, random / systematic sampling of plants ;\n2 (take leaves) from same species, that is present in both habitats ;\n3 collect a minimum of 5 leaf samples (in both habitats) ;\n4 same position / age, of leaf (on plant) ;\n5 impressions to be taken from, lower / upper / both / same, surface(s) (of leaves) ;\n6 (impressions viewed using) same, magnification / lens / size of field of view ;\n7 count stomata (in field of view) ;\n8 details of systematic counting / count only whole stomata / take a photograph and mark ;\n9 repeat, (same) experiment (both habitats) minimum of twice, and calculate a mean ;\n10 safety: hazard and risk and mitigation ;\n\n1(b)(i) 73 (%) ; 1\n© UCLES 2022 Page 7 of 10\n\n1(b)(ii) support – max 2 marks: 3\n1 stomatal density on upper surface is higher in plants grown in high light intensity ora ;\n2 difference in (mean) stomatal density on upper surface (between the two light intensities) is greater than the difference\nbetween the lower surfaces ora ;\n3 stomatal density on lower surface is similar / very close ;\n4 leaf 1 stomatal density on lower surface is less than in plants grown in low light intensity ora ;\n5 calculate pair of stomatal densities (for 1 to 4) ;\ndoesn’t support – max 2 marks:\n6 mean stomatal density, on lower / both, surface(s) is higher in plants grown in high light intensity ora ;\n7 for 2 out of 3 leaves / leaf 2 and 3, stomatal density is not higher only on the upper surface / is higher on lower / both,\nsurface(s) ;\n8 calculate pair of stomatal densities (for 6 / 7) ; ecf\n9 no statistical analysis done ;\n10 data only, for one species / L. esculentum ;\n© UCLES 2022 Page 8 of 10", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_51-p06.png", "../answer-assets/9700_s22_ms_51-p07.png", "../answer-assets/9700_s22_ms_51-p08.png" ] }, { "id": "9700-2022-mj-51-q02", "question_id": "9700-2022-mj-51-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 14, "status": "available", "reason": null, "text": "2(a)(i) any one from: 1\n(faecal samples) can be, collected remotely / AW, without harming the chimpanzees / investigators ;\n(faecal samples) are, non-invasive / less stressful for chimpanzees / limits human interaction / no risk of infection / no need to\nanesthetise chimpanzees ;\n\n2(a)(ii) any two from: 2\nmake into a, suspension / solution / liquify faeces ;\nfiltered / centrifuged (to remove solids) ;\n\n2(a)(iii) idea of: 1\ngenetic profiling / DNA fingerprinting / DNA profiling / DNA sequencing / genetic analysis / (DNA) electrophoresis ;\n\n2(b) any three from: 3\n1 (some) SIV antibodies will bind to HIV antigens ;\n2 details of, which / number of lines / bands, match / don’t match / AW ;\n3 (some) SIV and HIV antibodies have similar (protein), structures / shape ;\n4 HIV– people do not contain (HIV) antibodies / SIV– chimpanzees do not contain (SIV) antibodies ;\n5 the tests are valid as there is a line in each of the control regions ;\n\n2(c)(i) 1 allows for, valid / meaningful, comparison (between SIV+ and SIV– chimpanzees) ; 2\n2 the groups have different, initial / original numbers ;\n\n2(c)(ii) no difference between the, life expectancy / AW, of chimpanzees that are SIV+ and SIV– ; 1\n© UCLES 2022 Page 9 of 10\n\n2(c)(iii) mp1: 2\nprobability / it, is where null hypothesis is rejected ora ;\nor\nprobability / it, is where critical values are chosen ;\nmp2:\nless than, 0.05 / 5% / 5 in 100, probability that the, result / it, is not significant / is due to chance ;\nor\nmore than, 0.95 / 95% / 95 in 100, probability that the, result / it, is significant / is not due to chance ;\n\n2(c)(iv) any two from: 2\nidea that:\n1 results, may not be due to death from SIV / may be due to disappearance ;\n2 death could be due to, hunting / accident / fighting / predators / lack of food / disease (infectious or other) / AW ;\n3 ages of chimps were estimated ;\n4 uninfected chimpanzees may catch SIV during the investigation ;\n5 no data on, male/female chimps (as life expectancy may differ) ;\n© UCLES 2022 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_51-p09.png", "../answer-assets/9700_s22_ms_51-p10.png" ] }, { "id": "9700-2022-mj-52-q01", "question_id": "9700-2022-mj-52-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 18, "status": "available", "reason": null, "text": "1(a)(i) width of red area after soaking 1\nor\nwidth of red area remaining ;\n\n1(a)(ii) axes correctly labelled for independent and dependent variable ; 2\nline / smooth curve, showing inverse correlation ;\n\n1(b)(i) any seven from: 7\n1 use, same / same age, beetroot ;\n2 minimum 5 cubes with different, size / dimensions ;\n3 widths evenly spaced / if stated must be within range 0.5–5 cm ;\n4 equipment for cutting / measurement of cubes ;\n5 calculate / AW, the SA:V ratio ;\n6 cubes are fully, covered / submerged, (by calcium hypochlorite) ;\n7 remove after, same / stated, time (minutes) ;\n8 method of maintaining the same temperature (once cubes are immersed) ;\n9 method of drying cubes (after soaking) ;\n10 cut in half and measure the width of the red tissue after soaking ;\n11 repeat experiment a minimum of twice and calculate a mean ;\n12 named hazard and risk and precaution ;\nhazard risk precaution\ncalcium Irritant / harmful / gloves / goggles\nhypochlorite toxic / corrosive PPE / tweezers\nscalpel cuts / injury, to cut away from\nskin fingers /\ncut on a tile\nbeetroot allergen gloves\n© UCLES 2022 Page 7 of 10\n\n1(b)(ii) Initialvolumeofredcubevolumefinalredcube 2\n1 ;\nInitialvolumeofredcube\n2 100 ;\n\n1(c)(i) 17% (student 4 at 65°C) ; 2\nmean given of 89.3 at 25°C ;\n\n1(c)(ii) any two from: 2\n1 all (cubes of) same, size / volume / dimension / number / SA:V ;\n2 use, same / same age of, beetroot ;\n3 sufficient water to cover the cubes completely ;\n4 same volume of water in each beaker ;\n5 same colorimeter ;\n6 stir / AW, before taking sample for colorimeter reading ;\n7 check / AW, temperature of water in beakers have equilibrated ;\n8 zero colorimeter / calibrate, before each readings ;\n9 use thermostatically controlled water-bath ;\n\n1(c)(iii) 1 more (betalain) released as temperature increased 2\nor\nas temperature increases more betalain released ;\nmax 1 from:\n2 membrane, fluidity / permeability / AW, increases as temperature increases ;\n3 membrane proteins denature, at high(er) temperatures ;\n© UCLES 2022 Page 8 of 10", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_52-p07.png", "../answer-assets/9700_s22_ms_52-p08.png" ] }, { "id": "9700-2022-mj-52-q02", "question_id": "9700-2022-mj-52-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 12, "status": "available", "reason": null, "text": "2(a) any three from: 3\n1 capture a large sample (from one area / more than one area) ;\n2 count / record, the number caught ;\n3 test and, count / record, the number infected ;\n4 number / population, of infected divided by, population / total number,  100 ;\n5 mark-release-recapture method and Lincoln Index ;\n\n2(b)(i) numbers (of infected badgers / cows) per unit area ; 2\nallow (valid) comparison (between infected cows and infected badgers) ;\n\n2(b)(ii) any three from: 3\n1 method of testing (for bTB in badgers and cows) ;\n2 year of data collection ;\n3 type / breed / of, cattle ;\n4 cattle kept, outdoors / indoors ;\n5 number of areas counted each year ;\n6 season / time of year, (data collected) ;\n\n2(c)(i) no, correlation / relationship, between the number of infected badgers and the number of affected cows. 1\nor\nno, correlation / relationship, in the occurrence of infection between badgers and cows ;\n© UCLES 2022 Page 9 of 10\n\n2(c)(ii) max 2 3\nsupport\n1 combined data / A–J / graph / Fig 2.2, shows a positive, correlation / relationship / correct correlation described ;\n2 combined data / A–J / graph / Fig 2.2, shows a significant, correlation / relationship ;\n3 (so) culling (infected) badgers lowers infection in cattle ;\nmax 2\ndoes not support – graph\n4 separated data / A–H and D–J are clustered ;\nor\nno data between 0.4 and 0.6 per km2 ;\n5 data taken from different years ;\ndoes not support – table\n6 separated data / A–H and D–J, shows a negative, correlation / relationship ;\n7 separated data / A–H and D–J, does not show a significant, correlation / relationship ;\n8 correlation does not mean causation ;\n9 only data sets from 10 areas / only 10 out of 30 study areas sampled ;\n10 data only from England / one country ;\n© UCLES 2022 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_52-p09.png", "../answer-assets/9700_s22_ms_52-p10.png" ] }, { "id": "9700-2022-mj-53-q01", "question_id": "9700-2022-mj-53-q01", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 19, "status": "available", "reason": null, "text": "1(a)(i) concentration / water potential, of sucrose (solution) ; 1\n\n1(a)(ii) (the coloured sucrose drop / it) would sink / AW ; 1\n\n1(a)(iii) 1 water, leaves potato (by osmosis) ; 2\n2 (sucrose) solution, becomes less dense ;\n\n1(b)(i) (add) 8 cm3 of stock solution with 12 cm3 of (distilled) water ; 1\n\n1(b)(ii) ref. to hazard and risk ; 1\n\n1(b)(iii) Any six from: 6\n1 use minimum of 5 different concentrations of sucrose solution ;\n2 method of maintaining the same temperature (once potato pieces are immersed) ;\n3 use same, type / age, of potato ;\n4 all pieces of potato are, the same / stated, dimensions ;\n5 method to create potato of a certain dimensions ;\n6 potato pieces are fully covered / submerged (by sucrose solution) ;\n7 remove after same / stated time ;\n8 ref. to measuring mass of potato before and after ;\n9 method of drying potato pieces (before measuring final mass) ;\n10 repeat experiment a minimum of twice and calculate a mean ;\n11 idea of repeat with new concentrations of sucrose to get closer to the equivalent sucrose concentration ;\n\n1(c) –1.15 ; 1\n© UCLES 2022 Page 7 of 10\n\n1(d)(i) any one from: 1\n1 data is continuous ;\n2 data is normally distributed ;\n3 comparing (two) means ;\n4 standard deviations are approximately the same ;\n5 fewer than 30 values / samples (for each potato) ;\n\n1(d)(ii) no difference between, the water potential of, the two types of potato / Record and Kerr’s Pink (potato) ; 1\n\n1(d)(iii) 38 ; 1\n\n1(d)(iv) any three from: 3\n1 critical value (at df = 38 and p = 0.05%) = 2.024 ;\n2 calculated (t–) value / 1.890 is < than critical (t–) value / 2.024 ; ora\n3 null hypothesis is accepted ;\n4 there is no significant difference (between the means of the water potentials of the two varieties of potato) ;\nQuestion Answer Marks", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_53-p07.png", "../answer-assets/9700_s22_ms_53-p08.png" ] }, { "id": "9700-2022-mj-53-q02", "question_id": "9700-2022-mj-53-q02", "subject": "9700", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "2(a) to, absorb / remove / take up, the carbon dioxide produced (during respiration of blowfly larvae) ; 1\n\n2(b) direction 1\nthe coloured fluid will, move upwards\nand\nexplanation\n(oxygen is, taken in / used in respiration) so,\ndecreases the, volume / pressure of gas (in test-tube) ;\n© UCLES 2022 Page 8 of 10\n\n2(c) 1 remove substance X ; 2\n2 replace X with an inert material / glass beads / AW ;\n\n2(d) any one from: 1\ntemperature ;\nnumber of, (blowfly) larvae ;\nmass of, (blowfly) larvae ;\nage of, (blowfly) larvae ;\nfood source for, (blowfly) larvae ;\nmass / number of, substance X / inert material / beads ;\ntime to, equilibrate ;\ntime, for measurement (of meniscus movement) ;\n\n2(e) any two from: 2\n1 the larvae were not fully adjusted / equilibrated ;\n2 the larvae were at a lower temperature (than the apparatus) ;\n3 the larvae were less active ;\n\n2(f) 5.34 ;; 2\nincorrect answer max one for working:\n(  0.52  68) ÷10 ;\n© UCLES 2022 Page 9 of 10\n\n2(g) 0.56 ;; 2\nincorrect answer max one for working:\n3.00 / 5.34 ;\n© UCLES 2022 Page 10 of 10", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2022-May-June/ms/9700_s22_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-may-june/9700_s22_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s22_ms_53-p08.png", "../answer-assets/9700_s22_ms_53-p09.png", "../answer-assets/9700_s22_ms_53-p10.png" ] }, { "id": "9700-2022-on-41-q01", "question_id": "9700-2022-on-41-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 habitat loss ;\n2 competition with / disease from, farm / invasive / alien, animals / species ;\n3 climate change ;\n4 hunting / poaching / killing by humans ;\n5 AVP ;\n\n1(b) any three from: 3\n1 global / international / worldwide (authority / advisory) ;\n2 (to give advice to) conserve / protect, nature / biodiversity / habitats ;\n3 assess / categorise, species conservation status ;\n4 ref. Red List (of Threatened Species) ;\n5 influence, governments / policy ;\n6 educate / raise awareness ;\n7 AVP ;\n© UCLES 2022 Page 5 of 19\n\n1(c) any four from: 4\n1 mating / IVF / (super-ovulate female plus) AI ;\n2 remove embryo (from, mated / artificially inseminated, female) ;\n3 check / select, healthy / normal / best, embryos ;\n4 may freeze embryos for, storage / later use ;\n5 implant embryos in (different female) uterus ;\n6 ref. surrogate (mother) ;\n7 ref. (named female reproductive) hormone(s) ;\n8 AVP ;\n© UCLES 2022 Page 6 of 19", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p05.png", "../answer-assets/9700_w22_ms_41-p06.png" ] }, { "id": "9700-2022-on-41-q02", "question_id": "9700-2022-on-41-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "2(a) chlorophyll a / chlorophyll b / () carotene ; 1\n\n2(b) any two from: 2\n1 action (spectrum) shows rate of photosynthesis for light, wavelengths / colours ;\n2 absorption (spectrum) shows how much each, wavelength / colour, is absorbed ;\n3 higher absorption gives higher photosynthesis ;\n\n2(c) any three from: 3\n1 ref. (named) enzymes ;\n2 high(er) temperature increases rate ;\n3 (temperature affects) photophosphorylation / light-dependent / Calvin cycle / light-independent / ESC formation ; ora\n4 enzymes denature at, too high a temperature / very high temperature / above optimum temperature ;\n5 AVP ;\n\n2(d) any three from: 3\n1 RuBP joins with CO to make, 6C intermediate / GP ;\n2\n2 GP to TP ;\n3 (GP → TP) uses ATP and reduced NADP ;\n4 TP → glucose / hexose → starch ;\n5 condensation / polymerisation / glycosidic bonds ;\n© UCLES 2022 Page 7 of 19", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p07.png" ] }, { "id": "9700-2022-on-41-q03", "question_id": "9700-2022-on-41-q03", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 14, "status": "available", "reason": null, "text": "3(a)(i) any pair (max 2) from: 2\n1 cristae / folds, let inner membrane expand ;\n2 when water enters (matrix), by osmosis / down water potential gradient ;\n3 inner membrane (relatively) impermeable to water ;\n4 (so) water does not enter (matrix), by osmosis / down water potential gradient ;\n5 inner membrane moves (H+) ions out of matrix ;\n6 so less water enters (matrix), by osmosis / down water potential gradient ;\n\n3(a)(ii) any three names plus explanations from: 3\n1 pyruvate, for link reaction / to bind to coenzyme A / to make acetyl (CoA) / to make reduced NAD / be dehydrogenated ;\n2 oxaloacetate to, accept acetyl / make citrate ;\n3 citrate to, make reduced NAD / be dehydrogenated ;\n4 enzymes to catalyse, link reaction / Krebs cycle ;\n5 oxygen to, accept electrons / accept protons / form water ;\n6 water as a, solvent / medium for reactions ;\n7 DNA / RNA, to make (named) respiratory, enzymes / proteins ;\n© UCLES 2022 Page 8 of 19\n\n3(a)(iii) any one from: 1\n1 so H+, cannot move through / must move through ATP synthase ;\n2 to maintain proton gradient ;\n\n3(b)(i) any four from: 4\n1 (H atoms) split into protons and electrons ;\n2 electrons, flow / move, down ETC ;\n3 (releases) energy used to move H+ to intermembrane space ;\n4 more / build-up of, H+ / positive charge, in intermembrane space ;\n5 (causes / sets up) proton / electrochemical, gradient ;\n\n3(b)(ii) any two from: 2\n1 (P) by facilitated diffusion or through a protein, channel / carrier ;\ni\n2 P and H+ move together ;\ni\n3 (as) H+ ions diffuse (through ATP synth(et)ase / to matrix) ;\n\n3(b)(iii) 1 constant / sufficient / correct, supply / amount of, ADP / reactant ; 2\n2 (so) ATP can continue to be made / so enough ATP can be made ;\n© UCLES 2022 Page 9 of 19", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p08.png", "../answer-assets/9700_w22_ms_41-p09.png" ] }, { "id": "9700-2022-on-41-q04", "question_id": "9700-2022-on-41-q04", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 add DNA to give a new (named), characteristic / protein ;\n2 restriction, enzyme / endonuclease, to obtain, gene / allele / section of DNA\nor\nrestriction, enzyme / endonuclease, to cut plasmid ;\n3 combine gene with / insert gene into, vector / plasmid ;\n4 introduce, (recombinant) vector / plasmid, to, bacterium / (named host) cell ;\n5 clone / multiply, (named, recombinant / GM) organism ;\n6 AVP ;\n\n4(b)(i) 1 stem cells, proliferate / divide / multiply / make new cells ; 2\n2 (correct) gene is, inherited by / passed on to / present in, new cells ;\n\n4(b)(ii) any two from: 2\n1 to switch gene on / so gene is expressed / allow transcription ;\n2 at right time / all the time / in sufficient quantities ;\n3 to allow binding of, RNA polymerase / transcription factors ;\n© UCLES 2022 Page 10 of 19\n\n4(b)(iii) any two from: 2\n1 retrovirus / new gene, could / must not, insert in wrong place / disrupt other genes ;\n2 could / must not, cause cancer ;\n3 could / must not, cause, infection / disease ;\n4 could / must not, cause, immune / allergic, response ;\n5 AVP ;\n\n4(c) any three from: 3\n1 HD is caused by a dominant allele ;\n2 adding a ‘normal’ recessive allele would not work ;\n3 gene editing can / we need to, delete / remove / inactivate, HD / mutant, allele / DNA ;\n4 ref. (surplus CAG) repeats / triplets / stutter ;\n© UCLES 2022 Page 11 of 19", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p10.png", "../answer-assets/9700_w22_ms_41-p11.png" ] }, { "id": "9700-2022-on-41-q05", "question_id": "9700-2022-on-41-q05", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "5(a) any five from: 5\n1 evolution / speciation / natural selection ;\n2 random / spontaneous ;\n3 mutations (occurred) ;\n4 adapting some plants to, alpine habitat / high altitude / mountains ;\n5 (in this habitat) these plants, survived / were selected for ;\n6 (selection pressure is / must resist) cold / strong winds / thin soil ;\n7 alleles for alpine features passed to offspring ;\n8 change in, allele frequency / gene pool (of population) ;\n9 population become, morphologically / physiologically / biochemically, different ;\n10 less, herbivores / competition, in new niche ;\n11 AVP ;\n\n5(b)(i) any three from: 3\n1 time period = from 0.95 million years (to present) ;\n2 mountains high enough to exceed treeline ;\n3 this provides alpine, habitat / region / niches ;\n© UCLES 2022 Page 12 of 19\n\n5(b)(ii) any two from: 2\n1 compare / find similarities in / find differences in, DNA ;\n2 of alpine species and related (lowland) species ;\n3 find (time) when species, evolved / separated / diverged / speciated ;\n4 many, DNA / base / nucleotide, differences / changes / mutations, means they, separated a long time ago / have a\ndistant common ancestor ;\n5 AVP ;\n© UCLES 2022 Page 13 of 19", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p12.png", "../answer-assets/9700_w22_ms_41-p13.png" ] }, { "id": "9700-2022-on-41-q06", "question_id": "9700-2022-on-41-q06", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 13, "status": "available", "reason": null, "text": "6(a) any four from: 4\n1 breed / cross, plants with desired (named) characteristics ;\n2 breed, better / best, offspring, repeatedly / for many generations ;\n3 (correct ref. to) inbreeding / line breeding ;\n4 (correct ref. to) hybridisation / outbreeding / outcrossing ;\n5 (gives) hybrid vigour / heterosis / outbreeding enhancement (in offspring) ;\n6 F1 have, same genotype / uniform phenotype ;\n7 AVP ;\n\n6(b)(i) any one from: 1\n1 (IR8) less likely to, fall over / lodge / collapse ;\n2 (IR8) higher proportion / more, of plant is, edible / grain ;\n\n6(b)(ii) check for, genes / alleles / DNA, for high yield and flood tolerance ; 1\n\n6(b)(iii) any one from: 1\n1 to, maintain high yield / increase yield / give higher yield ;\n2 to avoid inbreeding depression or to maintain, hybrid vigour / heterosis ;\n© UCLES 2022 Page 14 of 19\n\n6(c)(ii) any four from: 4\nvariety A:\n1 gibberellin binds to, receptor / GID1 ;\n2 DELLA protein breaks down ;\n3 PIF / transcription factor (released) to, bind to DNA / transcribe genes ;\n4 stem / internode / cell, elongation / growth, occurs ;\n5 A, is lele / has no Le allele ;\n6 A does not produce its own (active) gibberellin ;\nvariety B:\n7 does not respond to / no effect from, gibberellin ;\n8 lacks / has non-functional, gibberellin receptor ;\n\n6(c)(ii) any two from: 2\n1 (BZR1) binds to promoter ;\n2 to switch gene on / so gene is expressed / allow transcription ;\n3 allows binding of RNA polymerase (to DNA / promoter) ;\n© UCLES 2022 Page 15 of 19", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p14.png", "../answer-assets/9700_w22_ms_41-p15.png" ] }, { "id": "9700-2022-on-41-q07", "question_id": "9700-2022-on-41-q07", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "7(a) 1 symbols B / XB = (allele for) black (fur) 5\nG / XG = (allele for) ginger (fur) ;\nparents phenotypes tortoiseshell female ginger male\n2 parents genotypes XBXG XGY ;\n3 gametes XB XG XG Y ;\n4 offspring genotypes XBXG XBY XGXG XGY ;\n5 offspring phenotypes tortoiseshell black ginger ginger\nfemale male female male ;\n\n7(b) any three from: 3\n1 TYR codes for tyrosinase ;\n2 converts tyrosine into DOPA ;\n3 converts DOPA into dopaquinone ;\n4 dopaquinone converted to melanin ;\nQuestion Answer Marks", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p16.png" ] }, { "id": "9700-2022-on-41-q08", "question_id": "9700-2022-on-41-q08", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "8(a) A – distal convoluted tub(ul)e ; 3\nB – cortex ;\nC – loop of Henlé ;\n© UCLES 2022 Page 16 of 19\n\n8(b) any three from: 3\n1 as ADH concentration increases urine concentration increases ;\n2 as ADH concentration increases urine flow rate decreases ;\n3 as urine flow rate decreases urine concentration increases ;\n4 data quote with units ;\n5 AVP ;\n\n8(c) any five from: 5\n1 ADH binds to cell, surface / membrane, receptor (of collecting duct cells) ;\n2 ref. G protein / adenyl(ate) cyclase ;\n3 second messenger / cAMP ;\n4 protein kinase activated ;\n5 vesicles, move towards / fuse with, cell (surface) membrane ;\n6 correct ref. aquaporins ;\n7 collecting duct / cells / membrane, (more) permeable to water ;\n8 more water, leaves, lumen / nephron\nor\nmore water enters, blood / medulla ;\n© UCLES 2022 Page 17 of 19", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p16.png", "../answer-assets/9700_w22_ms_41-p17.png" ] }, { "id": "9700-2022-on-41-q09", "question_id": "9700-2022-on-41-q09", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "9(a) any four from: 4\nmotor / neurone\n1 resting potential higher ;\n2 –70 mV (motor) versus –90 mV (muscle) ;\n3 smaller change in membrane potential / smaller depolarisation ;\n4 110 mV (motor) versus 130 mV (muscle) ;\n5 action potential / depolarisation, takes less time / is faster ;\n6 (action potential) 2.7 ms (motor) versus 4 ms (muscle)\nor\n(depolarisation) 1 ms (motor) versus 2 ms (muscle) ;\n7 hyperpolarisation / relative refractory period, occurs ;\n\n9(b)(i) any three from: 3\n1 transverse / T- , tubules depolarised ;\n2 Ca2+ diffuse out of sarcoplasmic reticulum ;\n3 Ca2+ bind to troponin ;\n4 tropomyosin, moves from / exposes, binding sites ;\n5 for myosin on actin ;\n6 cross-bridges form / myosin (head) binds to actin ;\n© UCLES 2022 Page 18 of 19\n\n9(b)(ii) any one from: 1\n1 cross bridges break / myosin heads detach, at different times ;\n2 AVP ;\nQuestion Answer Marks", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p18.png", "../answer-assets/9700_w22_ms_41-p19.png" ] }, { "id": "9700-2022-on-41-q10", "question_id": "9700-2022-on-41-q10", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 5, "status": "available", "reason": null, "text": "10 1 internal ; 5\n2 negative feedback ;\n3 receptor(s) ;\n4 endocrine / islets of Langerhans /  and  ;\n5 glycogen ;\n© UCLES 2022 Page 19 of 19", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_41-p19.png" ] }, { "id": "9700-2022-on-42-q01", "question_id": "9700-2022-on-42-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "1(a) any three from: 3\n1 Red List ;\n2 e.g. threatened / endangered / extinct etc., species ;\n3 ref. education / spreads awareness ;\n4 provides a global forum for sharing expertise / AW ;\n5 provides advice about conservation issues ;\n\n1(b) 1 cattle at edge / old and weak cattle, (easy) for lions to kill (for food) ; 2\n2 (so) the remaining cattle can survive / AW ;\n\n1(c) any four from: 4\n1 female given, hormone / FSH / gonadotropins ;\n2 ref. to superovulation / AW ;\n3 (secondary) oocytes / ova, harvested / AW ; Ignore eggs\n4 detail of harvest ; e.g. use of fine needle / using ultrasound\n5 sperm / semen, added to (secondary) oocytes / ova ;\n6 cultured / AW, for several days / until embryo or blastocyst stage ; Ignore number of cells\n7 embryo / blastocyst, placed in uterus ;\n© UCLES 2022 Page 5 of 19", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p05.png" ] }, { "id": "9700-2022-on-42-q02", "question_id": "9700-2022-on-42-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "2(a)(i) any four from: 4\n1 glycolysis ;\n2 glucose to pyruvate ;\n3 pyruvate to ethanal by, decarboxylation / CO removal ;\n2\n4 ethanal, reduced / hydrogenated, to ethanol ;\n5 reduced NAD to NAD ; A regeneration of NAD\n6 AVP ; e.g. ethanol / alcohol, dehydrogenase or pyruvate decarboxylase\n\n2(a)(ii) any two from: 2\n1 can survive (in absence of oxygen) ;\n2 (as) ATP still produced (from glycolysis) ;\n3 glycolysis can continue ;\n4 as NAD recycled ;\n\n2(b) any two from: 2\n1 GM strain has higher (concentration of ethanol / ethanol production)\nor\nGM strain has steeper increase (in concentration of ethanol / ethanol production) ; ora\n2 (both GM and non-GM) (concentration of ethanol / ethanol production) increases then levels off ;\n3 comparative figs to support trend ; e.g.\n(mp1) (max concentration) for GM 19 g dm–3 and non-GM 1 g dm–3\n(mp2) (levels off at) 18 g dm–3 for GM and 1 g dm–3 for non-GM\n© UCLES 2022 Page 6 of 19\n\n2(c) any two from: 2\n1 similar / same, concentration of starch hydrolysed ;\n2 similar / same, concentration of glucose available (to yeast) ;\n3 enzymes work at the same rate (in both methods) ;\n4 AVP ; e.g. GM yeast cells produce more enzymes\n\n2(d) any one from: 1\n1 more (named) fuel or electricity needed ;\n2 need to add enzymes ;\n3 AVP ; e.g. (whole method) takes longer\n© UCLES 2022 Page 7 of 19", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p06.png", "../answer-assets/9700_w22_ms_42-p07.png" ] }, { "id": "9700-2022-on-42-q03", "question_id": "9700-2022-on-42-q03", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "3(a)(i) D ; 2\nB ;\n\n3(a)(ii) any four from: 4\n1 thylakoid stacks or discs / many thylakoids, for, increased or large, surface area ;\n2 increased or large, surface area maximises the absorption of light (energy) / AW ; Ignore trap (light energy)\nmp 3–5 thylakoid membranes / grana contain\n3 photosynthetic / named / primary / accessory, pigments to absorb light (energy) ;\n4 electron carriers / ETC, to, transfer / release, energy (from excited electrons) ;\n5 photosystems / antenna complex and reaction centre, are light harvesting structures ;\n6 thylakoid space or lumen to, form proton gradient / have high concentration of protons ;\n7 thylakoid membrane is (relatively) impermeable, to maintain the proton gradient (for chemiosmosis) ;\n8 ATP synthase to make ATP ;\n9 contains oxygen-evolving complex / OEC, for the photolysis of water ;\n© UCLES 2022 Page 8 of 19\n\n3(b)(i) any three from: 3\n1 the pH is higher in the light than in the dark ora\nor\nthe pH increases (from dark) to light\nor\nthe pH decreases (from light) to dark ;\n2 the pH, increases sharply / AW, when changed to light ;\n3 the pH, levels off / AW, in light ;\n4 the pH decreases, gradually / less steeply, when returned to the dark\nor\ndecrease in pH does not return to original (dark) pH ;\n5 ref. to fluctuations anywhere / described ;\n6 comparative figures to support ;\n(mp1) dark(1) ~ pH 7.31–7.6 vs light ~ 7.52–7.61 vs dark (2) ~ 7.51–7.38\n(mp2) from pH 7.36–7.56 in 36 s (1½ squares and each square 24 s)\n(mp4) from pH 7.56–7.4 in 288 s (12 squares)\n\n3(b)(ii) any three from: 3\n1 the stroma has higher pH when H+ ions, move, out (of stroma) / into thylakoid, space / lumen ;\n2 (leads to) increased H+ concentration in the thylakoid, space / lumen ;\n3 (then) H+ diffuse back (into stroma) through ATP synthase ;\n4 AVP ; e.g. idea not to support theory\n© UCLES 2022 Page 9 of 19", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p08.png", "../answer-assets/9700_w22_ms_42-p09.png" ] }, { "id": "9700-2022-on-42-q04", "question_id": "9700-2022-on-42-q04", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 manipulate DNA to modify organism’s characteristics / AW ;\n2 gene / allele / (section of) DNA, obtained using restriction, enzyme / endonuclease ;\n3 use of reverse transcriptase to make, gene / allele / (section of) DNA, using mRNA ;\n4 gene / allele / (section of) DNA, inserted into, vector / plasmid, using ligase ;\n5 add / insert, (recombinant), vector / plasmid, into, (host) cell / bacterium ;\n6 clone / multiply, cell / bacteria ; A put bacteria in a fermenter\n7 gene is expressed and, protein / factor XIII / factor IX, is made ;\n8 AVP ; e.g. artificial / chemical, synthesis of new gene\n\n4(b)(i) any three from: 3\n1 haemophilia B (first) because (F9) gene is small enough to fit into virus / 1.6kbp and 4.7kbp ; ora\n2 haemophilia A (first) because it is more common ; ora\ntherapy not attempted\n3 (because) disease can be managed by recombinant proteins ;\n4 gene therapy (trials) involve, risk of harm / side effects / allergic reactions / immune response ;\ntherapy attempted\n5 provides a cure / AW ;\n6 taking clotting factors etc. can involve risk of harm ;\n© UCLES 2022 Page 10 of 19\n\n4(b)(ii) any two from: 2\n1 to allow binding of, RNA polymerase / transcription factors ;\n2 to switch gene on / so gene is expressed / allow transcription (of gene) ;\n3 at right time / all the time / in sufficient quantities ;\n4 in correct tissue ;\n\n4(b)(iii) any two from: 2\ndecrease success because:\n1 antibodies / immune response, may, destroy / attack / AW, virus / vector ;\n2 (so) limiting / stopping, delivery of, gene / allele / DNA, to cells ;\n3 destroys GM cells\nor\ndestroys cells that have successfully taken up the, virus / gene / allele / DNA ;\n\n4(c) any two from: 2\nlist rule\n1 (gene editing) is, precise / exact / accurate ;\n2 patient’s own gene can be, edited / corrected\nor\nno introduction of, gene / allele ;\n3 no need to introduce promoter ;\n4 less / no, risk of cancer\nor\nless / no, immune response ;\n© UCLES 2022 Page 11 of 19", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p10.png", "../answer-assets/9700_w22_ms_42-p11.png" ] }, { "id": "9700-2022-on-42-q05", "question_id": "9700-2022-on-42-q05", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "5(a) 1 at 95 °C, (DNA) denatures / (dsDNA) splits into single strands / H bonds break ; 3\n2 at 50 °C, primers, anneal / bind, (to ssDNA) ;\n3 at 72 °C, complementary / second, (DNA) strand is made ; A DNA replicated / (ssDNA) is made into dsDNA\n\n5(b) any four from 1–7: 5\n1 M. pygmaea (populations) geographically isolated / separated by sea or water ;\n2 M. pulvinaris (populations) geographically isolated / mountain tops separated ;\nM. pygmea or M. pulvinaris / South Island or Stewart Island species:\n3 no / little, interbreeding / gene flow, between populations ;\n4 different, selection pressures / environment ;\n5 different / random, mutations ;\n6 different changes in allele frequencies / different gene pools ;\n7 (so) allopatric speciation could be occurring (within either species) / AW ;\nM. pottsiana / North Island species:\n8 no geographical isolation ;\n9 (so) interbreeding / gene flow, occurs, within / between, population(s) ;\n10 similar, selection pressures / environment ;\n© UCLES 2022 Page 12 of 19\n\n5(c) any two from: 2\n1 genetic drift / bottleneck / founder effect ;\n2 migration ;\n3 mutation ;\n4 artificial selection / selective breeding ;\n© UCLES 2022 Page 13 of 19", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p12.png", "../answer-assets/9700_w22_ms_42-p13.png" ] }, { "id": "9700-2022-on-42-q06", "question_id": "9700-2022-on-42-q06", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 13, "status": "available", "reason": null, "text": "6(a)(i) any three from: 3\n1 trp operon regulatory gene / trpR, codes for an inactive repressor\nand\nlac operon regulatory gene / lacI, codes for active repressor ;\n2 lac operon does not have an attenuator ; ora\n3 lac operon has fewer structural genes\nor\n3 vs 5 structural genes ;\n4 lac operon uses, an inducer / (allo)lactose\nand\ntrp operon uses, a repressor / tryptophan ;\n5 (allo)lactose, binds / inactivates, repressor, so repressor, leaves / cannot bind to, operator\nand\ntryptophan, binds / activates, repressor, so repressor can bind to operator ;\n6 (allo)lactose causes genes to be, transcribed / switched on / expressed\nand\ntryptophan causes genes to be not, transcribed / switched on / expressed ;\n\n6(a)(ii) any one from: 1\n1 (share) one promoter ;\n2 all, enzymes / proteins / products, work together ;\n\n6(a)(iii) structural genes: 2\ncode for, enzymes / structural proteins / non-regulatory proteins / rRNA / tRNA ;\nregulatory genes:\ncode for, proteins / products, that control, gene expression / transcription ;\nA code for, transcription factors / repressor proteins\n© UCLES 2022 Page 14 of 19\n\n6(a)(iv) any two from: 2\n1 end-product inhibition / negative feedback / feedback inhibition ;\n2 tryptophan, binds to / activates, repressor\nor\ntryptophan allows repressor to bind to operator ;\n3 tryptophan, stops / reduces, trpA or gene transcription / trpA or gene expression /\nprotein synthesis / tryptophan synthase being made ;\n\n6(b)(i) any four from: 4\n1 (gibberellin) binds to receptor ;\n2 ref. enzyme ;\n3 (enzyme causes) DELLA breakdown ;\n4 DELLA no longer, binds to / inhibits, transcription factor / PIF ;\n5 (so) transcription factor / PIF / RNA polymerase, binds to, DNA / promoter ;\n6 (growth) genes, switched on / expressed / transcribed ;\n\n6(b)(ii) mark first answer 1\ntranscription factor(s) ;\n© UCLES 2022 Page 15 of 19", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p14.png", "../answer-assets/9700_w22_ms_42-p15.png" ] }, { "id": "9700-2022-on-42-q07", "question_id": "9700-2022-on-42-q07", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "7(a) dominant – allele always has effect on phenotype / allele expressed in homozygote and heterozygote / allele always 2\nexpressed ;\nrecessive – allele only has effect on phenotype if dominant allele absent / only expressed in homozygote ;\n\n7(b) symbols ZB = allele for bronze feathers 5\nZb = allele for brown feathers ;\nparents phenotypes bronze male brown female\nparents genotypes ZBZb x ZbW ;\ngametes ZB Zb Zb W ;\noffspring genotypes ZBZb ZBW ZbZb ZbW ;\noffspring phenotypes bronze male bronze female brown male brown female;\necf for putting allele on W\necf for incorrect symbols with no superscript\necf for different letters for alleles\nno sex chromosomes = no marks\n\n7(c) 1 cross with brown female ; 3\n2 if all offspring bronze then male is, homozygous / ZBZB ;\n3 if (some offspring are bronze and) some are brown then male is, heterozygous / ZBZb ;\n© UCLES 2022 Page 16 of 19", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p16.png" ] }, { "id": "9700-2022-on-42-q08", "question_id": "9700-2022-on-42-q08", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "8(a) C pointing to the microvilli adjacent to the proximal convoluted tubule lumen ; 2\nP pointing to the basal membrane adjacent to the blood capillary ;\nlabel line must touch a membrane (not a space)\n\n8(b) any five from: 5\n1 microvilli for large surface area (for reabsorption) ;\n2 (large surface area) for many, cotransporters / carrier proteins ;\n3 cotransporter (proteins) to absorb sodium ions with, glucose / amino acids ; A idea of secondary active transport\n4 tight junctions between cells so substances have to pass through the cells / AW ;\n5 many mitochondria to produce ATP ;\n6 (ATP) for the sodium (potassium) pumps\nor\n(ATP) to pump / actively transport, sodium ions (into the blood) ;\n7 folded basal membrane for many sodium (potassium) pumps ;\n\n8(c) 2.00 2\n;\n0.03\n67 ;\n2.00–0.03\nif given then accept 66 ecf for second mark point only\n0.03\n© UCLES 2022 Page 17 of 19", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p17.png" ] }, { "id": "9700-2022-on-42-q09", "question_id": "9700-2022-on-42-q09", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 6, "status": "available", "reason": null, "text": "9(a) 3\nphase of action potential state of voltage-gated channels\nA 2\nC 1\nE 3\nF 3\nG 2 ;;;\n5 correct = 3 marks\n3/4 correct = 2 marks\n1/2 correct = 1 mark\n\n9(b) any three from: 3\n1 Schwann cells, wrap around the axon / form the myelin sheath ;\n2 insulates (axon) / prevents movement of ions ;\n3 depolarisation / action potentials, can only occur at nodes (of Ranvier) ;\n4 ref. to long(er) local circuits / (nodes are) 1–3 mm apart ;\n5 action potentials, move by saltatory conduction / jump from node to node ;\n6 speed of transmission is, fast(er) / 100 m s–1 ;\n© UCLES 2022 Page 18 of 19", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p18.png" ] }, { "id": "9700-2022-on-42-q10", "question_id": "9700-2022-on-42-q10", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 7, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 decreasing / low, blood glucose concentration causes, increase in glucagon concentration / glucagon secretion ;\n2 glucagon acts on liver cells ;\n3 glycogenolysis / described ; R is glucagon breaks down glycogen\n4 gluconeogenesis / described ;\n5 so, glucose is released into the blood / blood glucose concentration increases ;\n6 ref. to negative feedback ;\n\n10(b) complementary ; 3\nG-protein ;\nadenyl(yl) cyclase ;\n© UCLES 2022 Page 19 of 19", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_42-p19.png" ] }, { "id": "9700-2022-on-43-q01", "question_id": "9700-2022-on-43-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 habitat loss ;\n2 competition with / disease from, farm / invasive / alien, animals / species ;\n3 climate change ;\n4 hunting / poaching / killing by humans ;\n5 AVP ;\n\n1(b) any three from: 3\n1 global / international / worldwide (authority / advisory) ;\n2 (to give advice to) conserve / protect, nature / biodiversity / habitats ;\n3 assess / categorise, species conservation status ;\n4 ref. Red List (of Threatened Species) ;\n5 influence, governments / policy ;\n6 educate / raise awareness ;\n7 AVP ;\n© UCLES 2022 Page 5 of 19\n\n1(c) any four from: 4\n1 mating / IVF / (super-ovulate female plus) AI ;\n2 remove embryo (from, mated / artificially inseminated, female) ;\n3 check / select, healthy / normal / best, embryos ;\n4 may freeze embryos for, storage / later use ;\n5 implant embryos in (different female) uterus ;\n6 ref. surrogate (mother) ;\n7 ref. (named female reproductive) hormone(s) ;\n8 AVP ;\n© UCLES 2022 Page 6 of 19", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p05.png", "../answer-assets/9700_w22_ms_43-p06.png" ] }, { "id": "9700-2022-on-43-q02", "question_id": "9700-2022-on-43-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "2(a) chlorophyll a / chlorophyll b / () carotene ; 1\n\n2(b) any two from: 2\n1 action (spectrum) shows rate of photosynthesis for light, wavelengths / colours ;\n2 absorption (spectrum) shows how much each, wavelength / colour, is absorbed ;\n3 higher absorption gives higher photosynthesis ;\n\n2(c) any three from: 3\n1 ref. (named) enzymes ;\n2 high(er) temperature increases rate ;\n3 (temperature affects) photophosphorylation / light-dependent / Calvin cycle / light-independent / ESC formation ; ora\n4 enzymes denature at, too high a temperature / very high temperature / above optimum temperature ;\n5 AVP ;\n\n2(d) any three from: 3\n1 RuBP joins with CO to make, 6C intermediate / GP ;\n2\n2 GP to TP ;\n3 (GP → TP) uses ATP and reduced NADP ;\n4 TP → glucose / hexose → starch ;\n5 condensation / polymerisation / glycosidic bonds ;\n© UCLES 2022 Page 7 of 19", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p07.png" ] }, { "id": "9700-2022-on-43-q03", "question_id": "9700-2022-on-43-q03", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 14, "status": "available", "reason": null, "text": "3(a)(i) any pair (max 2) from: 2\n1 cristae / folds, let inner membrane expand ;\n2 when water enters (matrix), by osmosis / down water potential gradient ;\n3 inner membrane (relatively) impermeable to water ;\n4 (so) water does not enter (matrix), by osmosis / down water potential gradient ;\n5 inner membrane moves (H+) ions out of matrix ;\n6 so less water enters (matrix), by osmosis / down water potential gradient ;\n\n3(a)(ii) any three names plus explanations from: 3\n1 pyruvate, for link reaction / to bind to coenzyme A / to make acetyl (CoA) / to make reduced NAD / be dehydrogenated ;\n2 oxaloacetate to, accept acetyl / make citrate ;\n3 citrate to, make reduced NAD / be dehydrogenated ;\n4 enzymes to catalyse, link reaction / Krebs cycle ;\n5 oxygen to, accept electrons / accept protons / form water ;\n6 water as a, solvent / medium for reactions ;\n7 DNA / RNA, to make (named) respiratory, enzymes / proteins ;\n© UCLES 2022 Page 8 of 19\n\n3(a)(iii) any one from: 1\n1 so H+, cannot move through / must move through ATP synthase ;\n2 to maintain proton gradient ;\n\n3(b)(i) any four from: 4\n1 (H atoms) split into protons and electrons ;\n2 electrons, flow / move, down ETC ;\n3 (releases) energy used to move H+ to intermembrane space ;\n4 more / build-up of, H+ / positive charge, in intermembrane space ;\n5 (causes / sets up) proton / electrochemical, gradient ;\n\n3(b)(ii) any two from: 2\n1 (P) by facilitated diffusion or through a protein, channel / carrier ;\ni\n2 P and H+ move together ;\ni\n3 (as) H+ ions diffuse (through ATP synth(et)ase / to matrix) ;\n\n3(b)(iii) 1 constant / sufficient / correct, supply / amount of, ADP / reactant ; 2\n2 (so) ATP can continue to be made / so enough ATP can be made ;\n© UCLES 2022 Page 9 of 19", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p08.png", "../answer-assets/9700_w22_ms_43-p09.png" ] }, { "id": "9700-2022-on-43-q04", "question_id": "9700-2022-on-43-q04", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 add DNA to give a new (named), characteristic / protein ;\n2 restriction, enzyme / endonuclease, to obtain, gene / allele / section of DNA\nor\nrestriction, enzyme / endonuclease, to cut plasmid ;\n3 combine gene with / insert gene into, vector / plasmid ;\n4 introduce, (recombinant) vector / plasmid, to, bacterium / (named host) cell ;\n5 clone / multiply, (named, recombinant / GM) organism ;\n6 AVP ;\n\n4(b)(i) 1 stem cells, proliferate / divide / multiply / make new cells ; 2\n2 (correct) gene is, inherited by / passed on to / present in, new cells ;\n\n4(b)(ii) any two from: 2\n1 to switch gene on / so gene is expressed / allow transcription ;\n2 at right time / all the time / in sufficient quantities ;\n3 to allow binding of, RNA polymerase / transcription factors ;\n© UCLES 2022 Page 10 of 19\n\n4(b)(iii) any two from: 2\n1 retrovirus / new gene, could / must not, insert in wrong place / disrupt other genes ;\n2 could / must not, cause cancer ;\n3 could / must not, cause, infection / disease ;\n4 could / must not, cause, immune / allergic, response ;\n5 AVP ;\n\n4(c) any three from: 3\n1 HD is caused by a dominant allele ;\n2 adding a ‘normal’ recessive allele would not work ;\n3 gene editing can / we need to, delete / remove / inactivate, HD / mutant, allele / DNA ;\n4 ref. (surplus CAG) repeats / triplets / stutter ;\n© UCLES 2022 Page 11 of 19", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p10.png", "../answer-assets/9700_w22_ms_43-p11.png" ] }, { "id": "9700-2022-on-43-q05", "question_id": "9700-2022-on-43-q05", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "5(a) any five from: 5\n1 evolution / speciation / natural selection ;\n2 random / spontaneous ;\n3 mutations (occurred) ;\n4 adapting some plants to, alpine habitat / high altitude / mountains ;\n5 (in this habitat) these plants, survived / were selected for ;\n6 (selection pressure is / must resist) cold / strong winds / thin soil ;\n7 alleles for alpine features passed to offspring ;\n8 change in, allele frequency / gene pool (of population) ;\n9 population become, morphologically / physiologically / biochemically, different ;\n10 less, herbivores / competition, in new niche ;\n11 AVP ;\n\n5(b)(i) any three from: 3\n1 time period = from 0.95 million years (to present) ;\n2 mountains high enough to exceed treeline ;\n3 this provides alpine, habitat / region / niches ;\n© UCLES 2022 Page 12 of 19\n\n5(b)(ii) any two from: 2\n1 compare / find similarities in / find differences in, DNA ;\n2 of alpine species and related (lowland) species ;\n3 find (time) when species, evolved / separated / diverged / speciated ;\n4 many, DNA / base / nucleotide, differences / changes / mutations, means they, separated a long time ago / have a\ndistant common ancestor ;\n5 AVP ;\n© UCLES 2022 Page 13 of 19", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p12.png", "../answer-assets/9700_w22_ms_43-p13.png" ] }, { "id": "9700-2022-on-43-q06", "question_id": "9700-2022-on-43-q06", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 13, "status": "available", "reason": null, "text": "6(a) any four from: 4\n1 breed / cross, plants with desired (named) characteristics ;\n2 breed, better / best, offspring, repeatedly / for many generations ;\n3 (correct ref. to) inbreeding / line breeding ;\n4 (correct ref. to) hybridisation / outbreeding / outcrossing ;\n5 (gives) hybrid vigour / heterosis / outbreeding enhancement (in offspring) ;\n6 F1 have, same genotype / uniform phenotype ;\n7 AVP ;\n\n6(b)(i) any one from: 1\n1 (IR8) less likely to, fall over / lodge / collapse ;\n2 (IR8) higher proportion / more, of plant is, edible / grain ;\n\n6(b)(ii) check for, genes / alleles / DNA, for high yield and flood tolerance ; 1\n\n6(b)(iii) any one from: 1\n1 to, maintain high yield / increase yield / give higher yield ;\n2 to avoid inbreeding depression or to maintain, hybrid vigour / heterosis ;\n© UCLES 2022 Page 14 of 19\n\n6(c)(ii) any four from: 4\nvariety A:\n1 gibberellin binds to, receptor / GID1 ;\n2 DELLA protein breaks down ;\n3 PIF / transcription factor (released) to, bind to DNA / transcribe genes ;\n4 stem / internode / cell, elongation / growth, occurs ;\n5 A, is lele / has no Le allele ;\n6 A does not produce its own (active) gibberellin ;\nvariety B:\n7 does not respond to / no effect from, gibberellin ;\n8 lacks / has non-functional, gibberellin receptor ;\n\n6(c)(ii) any two from: 2\n1 (BZR1) binds to promoter ;\n2 to switch gene on / so gene is expressed / allow transcription ;\n3 allows binding of RNA polymerase (to DNA / promoter) ;\n© UCLES 2022 Page 15 of 19", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p14.png", "../answer-assets/9700_w22_ms_43-p15.png" ] }, { "id": "9700-2022-on-43-q07", "question_id": "9700-2022-on-43-q07", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "7(a) 1 symbols B / XB = (allele for) black (fur) 5\nG / XG = (allele for) ginger (fur) ;\nparents phenotypes tortoiseshell female ginger male\n2 parents genotypes XBXG XGY ;\n3 gametes XB XG XG Y ;\n4 offspring genotypes XBXG XBY XGXG XGY ;\n5 offspring phenotypes tortoiseshell black ginger ginger\nfemale male female male ;\n\n7(b) any three from: 3\n1 TYR codes for tyrosinase ;\n2 converts tyrosine into DOPA ;\n3 converts DOPA into dopaquinone ;\n4 dopaquinone converted to melanin ;\nQuestion Answer Marks", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p16.png" ] }, { "id": "9700-2022-on-43-q08", "question_id": "9700-2022-on-43-q08", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "8(a) A – distal convoluted tub(ul)e ; 3\nB – cortex ;\nC – loop of Henlé ;\n© UCLES 2022 Page 16 of 19\n\n8(b) any three from: 3\n1 as ADH concentration increases urine concentration increases ;\n2 as ADH concentration increases urine flow rate decreases ;\n3 as urine flow rate decreases urine concentration increases ;\n4 data quote with units ;\n5 AVP ;\n\n8(c) any five from: 5\n1 ADH binds to cell, surface / membrane, receptor (of collecting duct cells) ;\n2 ref. G protein / adenyl(ate) cyclase ;\n3 second messenger / cAMP ;\n4 protein kinase activated ;\n5 vesicles, move towards / fuse with, cell (surface) membrane ;\n6 correct ref. aquaporins ;\n7 collecting duct / cells / membrane, (more) permeable to water ;\n8 more water, leaves, lumen / nephron\nor\nmore water enters, blood / medulla ;\n© UCLES 2022 Page 17 of 19", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p16.png", "../answer-assets/9700_w22_ms_43-p17.png" ] }, { "id": "9700-2022-on-43-q09", "question_id": "9700-2022-on-43-q09", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "9(a) any four from: 4\nmotor / neurone\n1 resting potential higher ;\n2 –70 mV (motor) versus –90 mV (muscle) ;\n3 smaller change in membrane potential / smaller depolarisation ;\n4 110 mV (motor) versus 130 mV (muscle) ;\n5 action potential / depolarisation, takes less time / is faster ;\n6 (action potential) 2.7 ms (motor) versus 4 ms (muscle)\nor\n(depolarisation) 1 ms (motor) versus 2 ms (muscle) ;\n7 hyperpolarisation / relative refractory period, occurs ;\n\n9(b)(i) any three from: 3\n1 transverse / T- , tubules depolarised ;\n2 Ca2+ diffuse out of sarcoplasmic reticulum ;\n3 Ca2+ bind to troponin ;\n4 tropomyosin, moves from / exposes, binding sites ;\n5 for myosin on actin ;\n6 cross-bridges form / myosin (head) binds to actin ;\n© UCLES 2022 Page 18 of 19\n\n9(b)(ii) any one from: 1\n1 cross bridges break / myosin heads detach, at different times ;\n2 AVP ;\nQuestion Answer Marks", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p18.png", "../answer-assets/9700_w22_ms_43-p19.png" ] }, { "id": "9700-2022-on-43-q10", "question_id": "9700-2022-on-43-q10", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 5, "status": "available", "reason": null, "text": "10 1 internal ; 5\n2 negative feedback ;\n3 receptor(s) ;\n4 endocrine / islets of Langerhans /  and  ;\n5 glycogen ;\n© UCLES 2022 Page 19 of 19", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_43-p19.png" ] }, { "id": "9700-2022-on-51-q01", "question_id": "9700-2022-on-51-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a)(i) to allow, oxygen / air, to enter for respiration 1\nor\nbecause, bacterium / B. subtilis, respires aerobically / AW ;\n\n1(a)(ii) as, population growth of bacteria / bacterial growth, increases / AW, the, cloudier / more turbid, the culture broth 1\nor\nmeasuring the, turbidity / cloudiness, by eye against a cross in background / with a colorimeter / turbidity meter /\ncolour chart ;\n\n1(b) replace antibiotic with, (distilled) water / nutrient solution ; 1\n\n1(c) can improve: 2\nadd, catalase / peroxidase / manganese(IV) oxide ;\nexplain why:\nresults / effect / killing, B. subtilis / bacteria , is only due to, honey / MGO\nor\nresults / effect / killing, B. subtilis / bacteria, is not due to hydrogen peroxide ;\n\n1(d) description or table or diagram for 10%: 2\n1 Correct method to dilute stock (honey) solution to 10% ;\ntable\n2 At least five dilutions including 10% all with correct volumes of stock and nutrient solution including units ;\n\n1(e) independent variable 2\nMGO / Manuka / honey, concentration ;\ndependent variable\nturbidity ;\n© UCLES 2022 Page 5 of 11\n\n1(f) predict: 2\nlower concentration, tubes / AW, will be, turbid / cloudy\nor\nhigher concentration, tubes / AW, will be, clear / not cloudy\nor\nthe lower the concentration the more, turbid / cloudy, the tubes / AW ; ora\nexplain:\nMGO / (Manuka) honey, inhibits the growth of / kills, B. subtilis / bacteria\nor\nlower concentrations have less, ability / MGO, to, inhibit the growth of / kill, B. subtilis / bacteria ; ora\n© UCLES 2022 Page 6 of 11\n\n1(g) any five from: 5\n1 same / stated, volume of, culture / broth used ;\n2 same / stated, volume of Manuka honey ;\n3 mix / stir, honey (concentrations) and, culture / broth (prior to starting) ;\n4 method to measure turbidity ;\n5 idea that: write down / note / record, which concentration(s) the broth, is clear / is clearest ;\nany two from 6–8 ;;\n6 method of maintaining temperature (10°C – 50°C if stated)\n7 same / stated, time (left in incubator) (12–48 hours if stated)\n8 use a buffer to maintain pH (pH 4–10 if stated)\n9 repeat at least twice / 3 replicates and finding mean ;\n10 named hazard and risk and precaution ;\nHazard Risk Precaution\nLive cultures / bacterium / B. subtilis Allergy / Infection / irritation / toxic Wear gloves / goggles / mask / PPE\nHoney Allergy Wear gloves / goggles / mask / PPE\nBroth Irritant / allergy Wear gloves / goggles / mask / PPE\n\n1(h)(i) there is no difference in the effect / effectiveness, of Manuka (honey) and Germania (honey) ; 1\n© UCLES 2022 Page 7 of 11\n\n1(h)(ii) yes 1\nyes ;\nno\n\n1(h)(iii) results: 2\nManuka honey, kills more bacteria / is more effective (than Germania) ; ora\nstatistical analysis:\nfirst three / 1, 2 and 3, are significantly different\nor\nlast two / 4 and 5, not significantly different against MRSA\nor\n1 is only significant at p = 0.05\nor\n2 / 3, are significant at the, p = 0.01 / p = 0.001 ;\n© UCLES 2022 Page 8 of 11", "source_pages": [ 5, 6, 7, 8 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_51-p05.png", "../answer-assets/9700_w22_ms_51-p06.png", "../answer-assets/9700_w22_ms_51-p07.png", "../answer-assets/9700_w22_ms_51-p08.png" ] }, { "id": "9700-2022-on-51-q02", "question_id": "9700-2022-on-51-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a) any one from: 1\nTo ensure no gossypol in any of the cows / to remove gossypol from cows\nor\nidea of: feeding on same diet standardises cows (for start of experiment) ;\n\n2(b)(i) any three from: 3\n1 the (mean) milk yields are, very close / similar, between groups ;\n2 no statistical test\nor\nshould carry out a, statistical test / t-test ;\n3 overlap of SE (then no significant difference) ;\n4 detail of which groups, are not / may be, significantly different ;\nnot significantly may be significantly\ndifferent different\nA and B A and E\nA and C B and E\nA and D C and E\nB and C D and E\nB and D\nC and D\n© UCLES 2022 Page 9 of 11\n\n2(b)(ii) any two from: 2\nenough evidence because:\n1 trend that as gossypol (in diet) increases, milk yield increases ; ora\n2 paired data quote (to support) ;\nnot enough evidence because:\n3 idea that: no information that differences in milk yield are caused by (differences in) gossypol ;\n4 idea that: no information on, nutritional content / AW, of , no gossypol diet / GM cottonseed ;\n5 idea that: there is no cottonseed in A so cannot compare with (diets) B to E\nor\nThere is only soybean in A so cannot compare with (diets) B to E ;\n6 no statistical test\nor\nshould carry out a, statistical test / t-test ;\n\n2(c)(i) there is a relationship because: 1\nas free (gossypol) intake increases, plasma (gossypol) concentration increases\nor\nshows a positive correlation ;\n© UCLES 2022 Page 10 of 11\n\n2(c)(ii) allow description of diet instead of group B, etc. 3\nany three from:\n1 (Group) E has the highest risk (of toxicity)\nor\n(Group) C has the lowest risk (of toxicity) ;\n2 sequence of risk, highest to lowest, is E →B →D →C ;\n3 ref. to higher free gossypol and (–) isomer values for highest risks\nor\nref. to lower free gossypol and (–) isomer values for lower risks ;\n4 paired data quote from Table 2.2 to support mp 2 or 3 ;\n5 free gossypol will be easily absorbed and more toxic (than bound gossypol)\nor\nBound gossypol is less easily absorbed and less toxic / not toxic ;\n6 idea that: uncertain how much free gossypol turns into bound gossypol when eaten ;\n7 AVP ;\n© UCLES 2022 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_51-p09.png", "../answer-assets/9700_w22_ms_51-p10.png", "../answer-assets/9700_w22_ms_51-p11.png" ] }, { "id": "9700-2022-on-52-q01", "question_id": "9700-2022-on-52-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 use coloured filter / set wavelength ;\n2 calibrate colorimeter / set colorimeter (absorbance) to zero ;\n3 water (used to calibrate colorimeter) ;\n\n1(b)(i) From description or table: 2\n1 Correct method to dilute stock solution with water to 0.1% ;\nTable:\n2 At least five stated concentrations including 0.1%, all with correct volumes of stock and water including volume units\nand concentration unit ;\n\n1(b)(ii) independent variable 1\nprotein concentration\nand\ndependent variable\nabsorbance ;\n\n1(b)(iii) 1 x-axis protein concentration and % 2\nand\ny-axis absorbance and au or no units added ;\n2 line drawn showing positive correlation ;\n\n1(b)(iv) copper(II) ions, binding with the nitrogen atoms, that form peptide bonds ; 2\nwill have same number of peptide bonds ;\n© UCLES 2022 Page 5 of 10\n\n1(c) any six from: 6\n1 same / stated, volume of protein concentrations and egg ;\n2 same / stated, volume of biuret solution ;\n3 add / mix / stir, protein (concentrations) / egg and, biuret ;\n4 measure / record, absorbance / colorimeter reading, for (known) protein (concentrations) / egg ;\n5 use calibration curve to find protein conc. in egg ;\n6 dilute egg (suspension) by factor of 10 ;\n7 same / stated, concentration of biuret solution ;\n8 same / stated, time (for colour development) before taking reading ;\n9 3 replicates and finding mean ;\n© UCLES 2022 Page 6 of 10\n\n1(c) 10 named hazard and risk and precaution ;\nHazard Risk Precaution\nCorrosive\nBiuret solution Irritant\nModerate / medium, hazard / risk\nCorrosive\nSodium hydroxide Wear gloves / goggles / mask / PPE\nIrritant\nCorrosive\nIrritant\nCopper sulphate\nModerate / medium, hazard / risk\nHazardous to the aquatic environment Do not pour down sink\nEgg / Albumin / Protein Allergen Wear gloves / goggles / mask / PPE / do not consume\n11 multiply protein concentration in egg, by dilution factor (to obtain actual concentration of protein) ;\n© UCLES 2022 Page 7 of 10", "source_pages": [ 5, 6, 7 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_52-p05.png", "../answer-assets/9700_w22_ms_52-p06.png", "../answer-assets/9700_w22_ms_52-p07.png" ] }, { "id": "9700-2022-on-52-q02", "question_id": "9700-2022-on-52-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "2(a) any two from: 1\n1 same number of each sex ;\n2 same / similar, age\nor\nfive years old ;\n3 same, breed / type / AW (of sheep) ;\n4 same / similar, mass / size ;\n5 do not have, mutation / mutant allele / Huntington’s (disease / allele) / neurological disease ;\n\n2(b) any two from: 2\n1 DNA (sequencing), only identifies presence of genes ;\n2 RNA (sequencing) identifies, active / switched on / expressed, genes\nor\nDNA (sequencing) does not identify, active / switched on / expressed, genes ;\n3 more copies of (m)RNA (compared to DNA) ;\n4 quantity of RNA indicates level of gene expression ;\n\n2(c)(i) t-test ; 2\ncomparing means / continuous data / data has a normal distribution / comparing two samples with fewer than 30 values ;\n\n2(c)(ii) there is no difference in the mean counts between the OVT73 and control ; 1\n© UCLES 2022 Page 8 of 10\n\n2(c)(iii) any two from: 2\n1 to make a comparison ;\n2 to identify if OVT73 (mean) counts was higher / lower (than control) ;\n3 use of data from Table 2.1 to support mp2 ;\n\n2(d) max one from contribute 2\n1 two different testing kit used ;\n2 commercial kits used, so (presumably) accurate ;\n3 statistical tests / analysis were carried out ;\nmax one from improves\n4 (test) more sheep ;\n5 reanalyse the 10 genes using kit 1, to confirm there was significant difference ;\n6 (test) more tissue samples / test the same (tissue) samples again ;\n\n2(e)(i) 1.33 ; 1\n\n2(e)(ii) For anterior striatum, SE (ranges) do not overlap, suggesting there is a significant difference 1\nor\nFor cerebellum / motor cortex, SE (ranges) do overlap, so there is not a significant difference ;\n\n2(e)(iii) more urea (in cell), so more transport proteins, more removal of urea ; 1\n© UCLES 2022 Page 9 of 10\n\n2(f) any two from: 2\n1 none of the genes coded for enzymes in the urea cycle ;\n2 no loss of (striatal) neurones (in OVT73 / transgenic sheep) ;\n3 more, urea produced / transport proteins made / gene expression so cells require more energy ;\n© UCLES 2022 Page 10 of 10", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_52-p08.png", "../answer-assets/9700_w22_ms_52-p09.png", "../answer-assets/9700_w22_ms_52-p10.png" ] }, { "id": "9700-2022-on-53-q01", "question_id": "9700-2022-on-53-q01", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a)(i) to allow, oxygen / air, to enter for respiration 1\nor\nbecause, bacterium / B. subtilis, respires aerobically / AW ;\n\n1(a)(ii) as, population growth of bacteria / bacterial growth, increases / AW, the, cloudier / more turbid, the culture broth 1\nor\nmeasuring the, turbidity / cloudiness, by eye against a cross in background / with a colorimeter / turbidity meter /\ncolour chart ;\n\n1(b) replace antibiotic with, (distilled) water / nutrient solution ; 1\n\n1(c) can improve: 2\nadd, catalase / peroxidase / manganese(IV) oxide ;\nexplain why:\nresults / effect / killing, B. subtilis / bacteria , is only due to, honey / MGO\nor\nresults / effect / killing, B. subtilis / bacteria, is not due to hydrogen peroxide ;\n\n1(d) description or table or diagram for 10%: 2\n1 Correct method to dilute stock (honey) solution to 10% ;\ntable\n2 At least five dilutions including 10% all with correct volumes of stock and nutrient solution including units ;\n\n1(e) independent variable 2\nMGO / Manuka / honey, concentration ;\ndependent variable\nturbidity ;\n© UCLES 2022 Page 5 of 11\n\n1(f) predict: 2\nlower concentration, tubes / AW, will be, turbid / cloudy\nor\nhigher concentration, tubes / AW, will be, clear / not cloudy\nor\nthe lower the concentration the more, turbid / cloudy, the tubes / AW ; ora\nexplain:\nMGO / (Manuka) honey, inhibits the growth of / kills, B. subtilis / bacteria\nor\nlower concentrations have less, ability / MGO, to, inhibit the growth of / kill, B. subtilis / bacteria ; ora\n© UCLES 2022 Page 6 of 11\n\n1(g) any five from: 5\n1 same / stated, volume of, culture / broth used ;\n2 same / stated, volume of Manuka honey ;\n3 mix / stir, honey (concentrations) and, culture / broth (prior to starting) ;\n4 method to measure turbidity ;\n5 idea that: write down / note / record, which concentration(s) the broth, is clear / is clearest ;\nany two from 6–8 ;;\n6 method of maintaining temperature (10°C – 50°C if stated)\n7 same / stated, time (left in incubator) (12–48 hours if stated)\n8 use a buffer to maintain pH (pH 4–10 if stated)\n9 repeat at least twice / 3 replicates and finding mean ;\n10 named hazard and risk and precaution ;\nHazard Risk Precaution\nLive cultures / bacterium / B. subtilis Allergy / Infection / irritation / toxic Wear gloves / goggles / mask / PPE\nHoney Allergy Wear gloves / goggles / mask / PPE\nBroth Irritant / allergy Wear gloves / goggles / mask / PPE\n\n1(h)(i) there is no difference in the effect / effectiveness, of Manuka (honey) and Germania (honey) ; 1\n© UCLES 2022 Page 7 of 11\n\n1(h)(ii) yes 1\nyes ;\nno\n\n1(h)(iii) results: 2\nManuka honey, kills more bacteria / is more effective (than Germania) ; ora\nstatistical analysis:\nfirst three / 1, 2 and 3, are significantly different\nor\nlast two / 4 and 5, not significantly different against MRSA\nor\n1 is only significant at p = 0.05\nor\n2 / 3, are significant at the, p = 0.01 / p = 0.001 ;\n© UCLES 2022 Page 8 of 11", "source_pages": [ 5, 6, 7, 8 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_53-p05.png", "../answer-assets/9700_w22_ms_53-p06.png", "../answer-assets/9700_w22_ms_53-p07.png", "../answer-assets/9700_w22_ms_53-p08.png" ] }, { "id": "9700-2022-on-53-q02", "question_id": "9700-2022-on-53-q02", "subject": "9700", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a) any one from: 1\nTo ensure no gossypol in any of the cows / to remove gossypol from cows\nor\nidea of: feeding on same diet standardises cows (for start of experiment) ;\n\n2(b)(i) any three from: 3\n1 the (mean) milk yields are, very close / similar, between groups ;\n2 no statistical test\nor\nshould carry out a, statistical test / t-test ;\n3 overlap of SE (then no significant difference) ;\n4 detail of which groups, are not / may be, significantly different ;\nnot significantly may be significantly\ndifferent different\nA and B A and E\nA and C B and E\nA and D C and E\nB and C D and E\nB and D\nC and D\n© UCLES 2022 Page 9 of 11\n\n2(b)(ii) any two from: 2\nenough evidence because:\n1 trend that as gossypol (in diet) increases, milk yield increases ; ora\n2 paired data quote (to support) ;\nnot enough evidence because:\n3 idea that: no information that differences in milk yield are caused by (differences in) gossypol ;\n4 idea that: no information on, nutritional content / AW, of , no gossypol diet / GM cottonseed ;\n5 idea that: there is no cottonseed in A so cannot compare with (diets) B to E\nor\nThere is only soybean in A so cannot compare with (diets) B to E ;\n6 no statistical test\nor\nshould carry out a, statistical test / t-test ;\n\n2(c)(i) there is a relationship because: 1\nas free (gossypol) intake increases, plasma (gossypol) concentration increases\nor\nshows a positive correlation ;\n© UCLES 2022 Page 10 of 11\n\n2(c)(ii) allow description of diet instead of group B, etc. 3\nany three from:\n1 (Group) E has the highest risk (of toxicity)\nor\n(Group) C has the lowest risk (of toxicity) ;\n2 sequence of risk, highest to lowest, is E →B →D →C ;\n3 ref. to higher free gossypol and (–) isomer values for highest risks\nor\nref. to lower free gossypol and (–) isomer values for lower risks ;\n4 paired data quote from Table 2.2 to support mp 2 or 3 ;\n5 free gossypol will be easily absorbed and more toxic (than bound gossypol)\nor\nBound gossypol is less easily absorbed and less toxic / not toxic ;\n6 idea that: uncertain how much free gossypol turns into bound gossypol when eaten ;\n7 AVP ;\n© UCLES 2022 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2022-Oct-Nov/ms/9700_w22_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2022-oct-nov/9700_w22_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w22_ms_53-p09.png", "../answer-assets/9700_w22_ms_53-p10.png", "../answer-assets/9700_w22_ms_53-p11.png" ] }, { "id": "9700-2023-m-42-q01", "question_id": "9700-2023-m-42-q01", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 10, "status": "available", "reason": null, "text": "1(a) 4\nregion of kidney\nlocation of loops of Henle C ;\nlocation of Bowman’s capsules A ;\nlocation of glomeruli A ;\ncontains urine at final concentration B + D ;\n\n1(b) any three from: 3\n1 (aquaporins are) water channel (proteins) ;\n2 (more) aquaporins increase (cell surface) membrane permeability (to water) ; ora\n3 of collecting duct (cells) ; I distal convoluted tubule cells\n4 allow water to, be reabsorbed / move into tissue fluid or blood ;\n\n1(c) any three from: 3\n1 detected by osmoreceptors ;\n2 in hypothalamus ;\n3 (osmoreceptors send) fewer impulses to posterior pituitary ; I signals\n4 less ADH, released / produced ; I no ADH released\n© UCLES 2023 Page 5 of 20", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p05.png" ] }, { "id": "9700-2023-m-42-q02", "question_id": "9700-2023-m-42-q02", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) 1 is regulatory gene / codes for repressor (protein) ; R is a transcription factor 2\nR lacI is a repressor protein\n2 prevents, transcription / RNA polymerase binding to promoter ;\n\n2(a)(ii) any three from: 3\nconcentration of IFN- produced\n1 increases steeply (after addition of IPTG) ;\n2 peak is, at 8 hours / 4 hours (after addition of IPTG) ;\n3 decrease is less steep\nor\nfinal concentration greater than starting concentration / AW ;\n4 data quote ;\n\n2(a)(iii) any one from: 1\nIPTG is higher / lactose is lower, because\n1 lactose has to be converted to allolactose ;\n2 lactose is broken down so needs to be continually taken up\nor\nIPTG is not broken down so continually binds to repressor ;\n3 IPTG will be at higher concentration than allolactose ; A lactose for allolactose\n4 IPTG has higher affinity for repressor protein than allolactose ; A lactose for allolactose\n5 lactose, used up / concentration decreases ;\n6 more IPTG enters ;\n© UCLES 2023 Page 6 of 20\n\n2(a)(iv) IFN- is, unstable / breaks down ; 1\n\n2(b) (only E. coli that have taken up the plasmid) will, grow / survive, in the presence of, ampicillin / antibiotic ; 1\n\n2(c) any five from: 5\n1 (random) mutation ;\n2 natural selection / directional selection ;\n3 antibiotic acts as selection pressure / AW ;\n4 bacteria with mutation, have selective advantage / survive / reproduce\nor\nbacteria with, gene / allele, that codes for antibiotic resistance, have selective advantage / survive / reproduce ;\n5 pass on, mutation / gene / allele, (for antibiotic resistance) by, binary fission / asexual reproduction / vertical\ntransmission ;\n6 pass on, mutation / gene / allele, (for antibiotic resistance) by, transduction / transformation / conjugation / horizontal\ntransmission ;\n7 AVP ; e.g. increased chance of resistance if people do not finish full course of antibiotics\noveruse of antibiotics\nsome antibiotics may act as mutagens\n© UCLES 2023 Page 7 of 20", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p06.png", "../answer-assets/9700_m23_ms_42-p07.png" ] }, { "id": "9700-2023-m-42-q03", "question_id": "9700-2023-m-42-q03", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "3(a) any three from: 3\nmax two from:\n1 (phenotype has) range of values / intermediates ;\n2 (phenotypes) not, in groups / in classes / categoric / discrete / qualitative\nor\n(phenotypes are) quantitative ;\n3 normal distribution ;\nmax two from:\n4 polygenic / controlled by many genes ;\n5 different genes / alleles, have additive effect ;\n6 (named) environmental factors (contribute to the variation) ;\n\n3(b)(i) difference between means = 9.4 – 7.7 or 1.7 ; 3\n2 2\n0.4 + 1.1\ndenominator =\n28 27\nor\n0.16 + 1.21\n28 27\nor\n0.22 / 0.23 (no limit on number of decimal places) ;\nt = 7.56 ; must be to 2 decimal places\nallow ECF\n© UCLES 2023 Page 8 of 20\n\n3(b)(ii) 1 t-value / 7.56, is greater than, 2.01 / critical value ; 3\n2 difference between two groups is, significant / not due to chance\nor\nnull hypothesis rejected ;\nany two from:\n3 overlap in, data range / error bars ;\n4 ref. to correlation does not prove causation ;\n5 only a single investigation / needs repeating / small sample size ;\n6 ref. to this is only at 5% probability so may not actually be different / AW ;\n7 t-test may not be valid due to unequal, standard deviations / variances;\n\n3(b)(iii) any one from: 1\n1 idea of less labour intensive ; e.g. no need for weekly injections / GM only needs to be done once\n2 idea of less stressful on GM salmon ;\n3 risk of infection with injections ;\n4 idea that growth hormone is continuously produced ;\n5 GM salmon may grow faster ;\n© UCLES 2023 Page 9 of 20", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p08.png", "../answer-assets/9700_m23_ms_42-p09.png" ] }, { "id": "9700-2023-m-42-q04", "question_id": "9700-2023-m-42-q04", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a) any three from: 3\n1 ref. to isolate / extract, DNA, from, cells / tissue / named ;\n2 ref. to cut DNA, into small fragments / using restriction enzymes ;\n3 ref. to denature / AW, into single-stranded DNA ;\n4 add fluorescent, tag / marker / dye ;\n\n4(b)(i) 2 400 000 or 2 500 000 ; 1\n\n4(b)(ii) any three from: 3\n1 DNA from DiGeorge syndrome and control DNA labelled with different colour fluorescent tags ;\n2 DNA hybridises with probes (on microarray) ;\nDiGeorge Syndrome\n3 less DNA binds to probes (than control DNA) ;\n4 so there is, less / 50%, fluorescence where nucleotides have been deleted ;\n5 fluorescence is, equal / 100%, where nucleotides have not been deleted ;\n© UCLES 2023 Page 10 of 20\n\n4(b)(iii) any three from: 3\n1 different number of nucleotides may be deleted ;\n2 different genes may be deleted ;\n3 an individual only has one allele (of the deleted genes) ;\n4 different individuals may have different alleles of the same gene\nor\nin one individual remaining allele may be recessive but dominant in another individual ;\n5 so different proteins made ;\n6 ref. to individuals may have different environments ; A diet\n© UCLES 2023 Page 11 of 20", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p10.png", "../answer-assets/9700_m23_ms_42-p11.png" ] }, { "id": "9700-2023-m-42-q05", "question_id": "9700-2023-m-42-q05", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "5(a) 4\nstage of meiosis spindle fibres diagram\nattach to centromeres and\narrange homologous pairs of\nmetaphase I\nchromosomes at the equator of\nthe cell\n(contract to) pull,\nanaphase I centromeres / chromosomes,\ntowards poles / to centrioles ;\nprophase II ; re-form spindle in daughter cells\n(forming) four daughter cells ;\ntwo single chromosomes\ntelophase II disassemble\ninside a (re-forming) nuclear\nenvelope ;\n© UCLES 2023 Page 12 of 20\n\n5(b) any four from: 4\n1 (meiosis / reduction division) produces gametes ;\n2 (two) gametes fuse / fertilisation occurs, to form a zygote ;\n3 zygote will have maternal and paternal chromosomes / AW ;\n4 gametes, are haploid / are n / have half the normal number (of chromosomes) ;\n5 so the zygote, is diploid / 2n ;\n6 prevents, doubling of chromosome number / polyploidy / having too many chromosomes\nor\nallows chromosome number to remain constant ;\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p12.png", "../answer-assets/9700_m23_ms_42-p13.png" ] }, { "id": "9700-2023-m-42-q06", "question_id": "9700-2023-m-42-q06", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "6(a)(i) D ; 1\n\n6(a)(ii) D and C ; 1\n\n6(b) any three from: 3\n1 site of, link reaction / Krebs cycle ;\n2 DNA / ribosomes, for production of proteins (used in respiration) ;\n3 named example ; e.g. enzymes / coenzymes / electron carriers ;\n4 production of, reduced FAD / reduced NAD, for oxidative phosphorylation ;\n5 substrate-linked phosphorylation ;\n© UCLES 2023 Page 13 of 20\n\n6(c) any four from: 4\nprocess, stops / decreases, because:\n1 no / fewer, electrons accepted by oxygen\nor\noxygen is the final electron acceptor ;\n2 no / fewer, electrons, enter / move along, electron transport chain / ETC\nor\nETC stops ;\n3 no /fewer, H+ pumped into intermembrane space\nor\nno / less steep, proton gradient ;\n4 no / less, chemiosmosis ;\n5 reduced NAD / reduced FAD, not oxidised /\nor\nNAD / FAD, not recycled ;\n6 no / less, ATP produced ;\n7 AVP ; e.g. no / less, pyruvate enters mitochondrion.\n© UCLES 2023 Page 14 of 20", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p13.png", "../answer-assets/9700_m23_ms_42-p14.png" ] }, { "id": "9700-2023-m-42-q07", "question_id": "9700-2023-m-42-q07", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 0.1 g dm–3 chemoreceptor (membrane), is not depolarised / does not release neurotransmitter / remains at resting\npotential ;\n2 so, dendrite / sensory neurone, is not depolarised / remains at resting potential / has no action potential ;\n3 1.0 g dm–3 / 10.0 g dm–3, chemoreceptor (membrane), is depolarised / releases neurotransmitter ;\n4 so, depolarisation / action potential / impulse, in, dendrite / sensory neurone ;\n5 receptor / generator, potential qualified ;\n6 ref. to threshold / all or nothing law (in context of either cell) ;\n\n7(b) any three from: 3\nsensory motor\n1 cell body, between dendron and and cell body, at end / in CNS ;\naxon / in ganglion\n2 has dendron and axon and has (long) axon ;\n3 no dendrites from cell body and dendrites extend from cell body\n;\n4 carries impulses from receptor and carries impulses from,\nto, CNS / intermediate neurone CNS / intermediate neurone, to\neffector ;\n© UCLES 2023 Page 15 of 20", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p15.png" ] }, { "id": "9700-2023-m-42-q08", "question_id": "9700-2023-m-42-q08", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "8(a) any seven from: 7\n1 photosynthetic / named / primary / accessory, pigments to absorb light (energy) ;\n2 ref. to, photosystems / antenna complex and reaction centre / light harvesting structures ;\n3 photoactivation / electrons excited / emission of electrons ;\n4 electrons move along electron transport chain ;\n5 (cyclic / non-cyclic) photophosphorylation / light-dependent stage ;\n6 site of photolysis / location of oxygen-evolving complex ;\n7 thylakoids stacked to form grana ;\n8 gives large surface area ;\n9 thylakoid space or lumen to, form proton gradient / have high concentration of protons ;\n10 thylakoid membrane is (relatively) impermeable, to maintain the proton gradient ;\n11 ATP synthase to make ATP;\n12 chemiosmosis ;\n© UCLES 2023 Page 16 of 20\n\n8(b) any four from: 4\ndescribe\n1 A activity increases and B activity remains, low / constant ;\n2 comparative data quote ;\ne.g. 3.0–3.2 at 0.5 mins and 11.4–11.6 at 6 mins for A\n0.4 throughout for B\nmax three:\nexplanation:\n3 RA / rubisco activase, activates rubisco ;\n4 by changing the active site of rubisco ;\n5 by enabling rubisco to bind more readily with, RuBP / substrate\nor\nmore enzyme–substrate complexes ;\n6 enables products to leave active site more quickly ;\n7 AVP ; e.g. cofactor action qualified\nQuestion Answer Marks", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p16.png", "../answer-assets/9700_m23_ms_42-p17.png" ] }, { "id": "9700-2023-m-42-q09", "question_id": "9700-2023-m-42-q09", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "9(a)(i) P pointing to thin filament ; 2\nR pointing to thick filament ;\n\n9(a)(ii) A-band – stays the same ; 2\nI-band – gets narrower ;\n© UCLES 2023 Page 17 of 20\n\n9(b)(i) any four from: 4\n1 competes with, acetylcholine / neurotransmitter\nor\nacetylcholine cannot bind to receptors\nor\nblocks receptors ;\n2 Na+ channels do not open\nor\nno / fewer, sodium ions enter (muscle fibre) ;\n3 so, no / less, depolarisation of sarcolemma ;\n4 no / fewer, action potentials / impulses (spread across muscle fibre) ;\n5 Ca2+ (voltage-gated) channels do not open in sarcoplasmic reticulum\nor\nno / fewer, Ca2+ ions released by sarcoplasmic reticulum ;\n6 no / fewer, Ca2+ ions bind to troponin\nor\nno exposing of binding sites\nor\nno / fewer, cross bridges / AW ;\n\n9(b)(ii) any two from: 2\n1 affects, rib muscles / intercostal muscles / diaphragm, so unable to breathe ;\n2 affects cardiac muscle so, stops blood circulation / heart failure / attack ;\n3 cannot move so unable to escape from predators ;\n4 cannot eat so starves ;\n© UCLES 2023 Page 18 of 20", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p17.png", "../answer-assets/9700_m23_ms_42-p18.png" ] }, { "id": "9700-2023-m-42-q10", "question_id": "9700-2023-m-42-q10", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "10(a) abundance / numbers / population (size) ; 6\nSimpson’s ;\ngenes ;\nalleles ;\nadapt / evolve ;\nhabitats / niches ;\n\n10(b)(i) 14234−7851 2\n;\n12\n532 ;\n© UCLES 2023 Page 19 of 20\n\n10(b)(ii) any four from: 4\nfish:\n1 overfishing ;\n2 (on water / at sea) difficult to enforce protective, laws / regulations\nor\nfewer laws to protect fish ;\n3 trophy hunting ;\n4 climate change qualified ; e.g. increased ocean temperatures /\npredatory species moving into new areas now water is warmer\n5 pollution qualified ; e.g. plastics in the sea / oil spills / eutrophication\n6 there are more species of fish than there are species of mammals ;\nmammals:\n7 more conservation projects for mammals / AW ; ora for fish\n8 laws in place, banning hunting / protecting mammals ;\n9 AVP ;\n© UCLES 2023 Page 20 of 20", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_42-p19.png", "../answer-assets/9700_m23_ms_42-p20.png" ] }, { "id": "9700-2023-m-52-q01", "question_id": "9700-2023-m-52-q01", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a)(i) any one from: 1\nuse coloured filter / set wavelength (of light) ;\ncalibrate colorimeter / set colorimeter (absorbance) to zero ;\nuse distilled water (to, calibrate colorimeter / set to zero) ;\n\n1(a)(ii) 1 5 stated concentrations and units ; 3\n2 (reasonably) evenly spaced ;\n3 method for dilution shown for at least 2 concentrations other than 2.0% and 0% ;\n\n1(a)(iii) correct axis labels and orientation ; 2\nx-axis label:\npercentage glucose concentration\ny-axis label:\nabsorbance (no units or absorbance units or arbitrary units)\nappropriately shaped line ;\nline with negative gradient\n\n1(b)(i) glucose concentration (of potato) ; 1\n© UCLES 2023 Page 5 of 10\n\n1(b)(ii) any six from: 6\n1 ref. to, same / stated, potatoes (used for investigation) ;\n2 ref. to, same / stated, storage conditions (of potatoes) ;\ne.g. (low) temperature\nin dark\ncarbon dioxide concentration\n3 additional stated storage condition (of potatoes) ;\n4 use minimum of 5 different storage times (of potatoes) ;\n5 ref. to stated storage times (of potatoes) ;\n6 ref. to, same / stated, volume of potato juice (for glucose assay) ;\n7 at each storage time, measure / note / record, absorbance (of potato juice used in glucose assay)\nor\nat each storage time carry out glucose assay ;\n8 repeat at least twice / 3 replicates for each storage time, and find a mean ;\n9 named hazard and risk and precaution ;\ne.g.\nhazard risk precaution\nBenedict’s reagent irritant gloves / eye protection / PPE\ntoxic (to aquatic environment) don’t pour down sink\nhot water (bath) burns / scalds use tongs / gloves / eye\nA water-bath protection\npotato allergy gloves / eye protection / PPE\nknife / scalpel injury cut away from hand\n© UCLES 2023 Page 6 of 10\n\n1(c) any two from: 2\n1 as gamma radiation dose increases, (percentage) volatile nitrogen compounds (in raw potatoes) decrease ;\n2 (percentage) volatile nitrogen compounds (in raw potatoes), are significantly different, at different doses of gamma\nradiation ;\n3 idea that no change in percentage glucose (in raw potatoes), therefore decrease in acrylamide in cooked potato chips,\nis not due to glucose / must be due to asparagine ;\n4 idea that decrease in volatile nitrogen compounds at increased gamma radiation doses indicates decrease of\nasparagine (so less acrylamide is made in the Maillard reaction) ;\n\n1(d)(i) (–)61 (%) ; 2\ncorrect working ;\n© UCLES 2023 Page 7 of 10\n\n1(d)(ii) any three from: 3\nsupports:\n1 idea that, gamma radiation and hot water treatment / treatment 2, decreases the (acrylamide) concentration (of potato\nchips) more than, gamma radiation only / treatment 1 ;\n2 idea that, 95% confidence intervals / 95% CI / error bars (for treatment 1 and treatment 2), do not overlap (at all\ngamma radiation doses), therefore treatment with radiation and hot water is significantly different from treatment with\nradiation alone ;\n3 paired data quote (to support) ;\ndoes not support:\n4 idea that hot water treatment alone decreases acrylamide concentration (of potato chips) ;\n5 idea that, 95% confidence intervals / 95% CI / error bars (for treatment 2), overlap (at all gamma radiation doses),\ntherefore decrease in acrylamide due to hot water treatment and gamma radiation is not significantly different from hot\nwater treatment alone) ;\n6 ref. to only one variety of potato investigated ;\n7 no statistical test\nor\nshould carry out a, statistical test ;\n© UCLES 2023 Page 8 of 10", "source_pages": [ 5, 6, 7, 8 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_52-p05.png", "../answer-assets/9700_m23_ms_52-p06.png", "../answer-assets/9700_m23_ms_52-p07.png", "../answer-assets/9700_m23_ms_52-p08.png" ] }, { "id": "9700-2023-m-52-q02", "question_id": "9700-2023-m-52-q02", "subject": "9700", "year": 2023, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) distance from GM rice plants 1\nand\ndirection from GM rice plants ;\n\n2(a)(ii) apply herbicide to young plants ; 2\ncount the number of young plants that survive ;\n\n2(a)(iii) any two from: 2\n1 as distance from GM rice plants increases, (percentage) gene flow decreases / pollen dispersal decreases ; ora\n2 (percentage) gene flow / distance of pollen dispersal, is higher in direction of (normal) wind / NW direction (than other\ndirections) ; ora\n3 pollen cannot disperse further than 10 m / no gene flow at 10m (or further) ;\n\n2(b)(i) 0.036 ; 1\n\n2(b)(ii) any three from: 3\n1 critical value (for p = 0.05) = 2.145\nor\ncritical value (for p = 0.01) = 2.977 ;\n2 value for t / 9.043 / calculated value, is greater than critical value ;\n3 null hypothesis is rejected ;\n4 there is a significant difference between percentage gene flow from GM rice plants to weedy rice plants and\npercentage gene flow from weedy rice plants to GM rice plants ;\n© UCLES 2023 Page 9 of 10\n\n2(b)(iii) any one from: 1\n1 investigation only, carried out once / not repeated ;\n2 investigation only on, wind-pollinated crop / one crop species / (GM and weedy) rice / one non-crop species ;\n3 investigation only investigated, one / two, gene(s) ;\n4 investigation only, in one geographical area ;\n5 investigation only in, experimental trials / without herbicide use ;\n6 no long-term data / no data over several generations ;\n7 gene flow (from GM plants to wild plants), was shown to occur ;\n8 idea that wild plants with herbicide-resistant gene, difficult to remove / have selective advantage ;\n© UCLES 2023 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-March/ms/9700_m23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-march/9700_m23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m23_ms_52-p09.png", "../answer-assets/9700_m23_ms_52-p10.png" ] }, { "id": "9700-2023-mj-41-q01", "question_id": "9700-2023-mj-41-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "1(a) 4\ndescription letter\naccumulates (builds up) a high concentration of protons B ;\nmakes triose phosphate A ;\nmakes some chloroplast proteins D ;\npumps protons C ;\n\n1(b)(i) any four from: 4\n1 spot / extract, placed on, pencil line / base line / line of origin ;\n2 repeat / concentrate, spot / extract ;\n3 end / base, of paper, suspended / placed, in (named) solvent ;\n4 mark the solvent front after, some time / paper removed / solvent moves ;\n5 R value = distance moved by, spot / pigment / component / solute ÷ distance moved by solvent (front) ;\nf\n6 compare (R) with known R values to identify, constituents / pigments ;\nf f\n7 detail of method ;\n\n1(b)(ii) any three from: 3\n1 (pigments / they / to) absorb / capture / harvest, light (energy) ;\n2 increase (range of) / more / different, wavelengths / colours of light, can be absorbed ;\n3 increase, efficiency / rate, of, photosynthesis / light dependent reaction OR\nincrease / broader, action spectrum ;\n4 ref. two of: chlorophyll a / chlorophyll b / carotene / xanthophyll ;\n© UCLES 2023 Page 8 of 17", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p08.png" ] }, { "id": "9700-2023-mj-41-q02", "question_id": "9700-2023-mj-41-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "2(a)(i) 1 (self-contained unit containing) community of / all / different, organisms / populations / species, and their interactions ; 2\n2 (with the) biotic and abiotic, environment / factors OR\nwith each other and with the physical environment ;\n\n2(a)(ii) role / function, of a species within its, ecosystem / habitat ; 1\n\n2(b)(i) (interrupted belt) transect ; 1\n\n2(b)(ii) were assessed: 3\n1 abundance / density / (%) frequency / % cover, of (selected) species ;\nnot assessed:\n2 number / range, of (different), ecosystems / habitats ;\n3 genetic, variation / diversity (within each species) ;\n\n2(c)(i) Haematopus / Larus ; 1\n\n2(c)(ii) any two from: 2\n1 eukaryotic (cells) ;\n2 autotrophic / photosynthetic ;\n3 cellulose cell wall ;\n4 aquatic ;\n5 not motile / sessile ;\n6 multicellular ;\n7 no, vascular tissue / xylem / phloem ;\n\n2(d) any four from: 4\n1 rats no longer, prey on / eat, birds / eggs / chicks ;\n2 mussels / sea snails, decrease because there are more (named) birds ;\n3 seaweeds increase because there are fewer, mussels / (sea) snails ;\n4 Hawadax has changed to match a rat-free island ;\n5 rats were an, invasive / alien, species / predator ;\n6 AVP ;\n© UCLES 2023 Page 9 of 17", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p09.png" ] }, { "id": "9700-2023-mj-41-q03", "question_id": "9700-2023-mj-41-q03", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 12, "status": "available", "reason": null, "text": "3(a)(i) any two from: 2\n1 oxygen / gas, supply / diffusion / transfer ;\n2 to, submerged / underwater, cells / tissues / roots ;\n3 for aerobic respiration ;\n\n3(a)(ii) any one from: 1\n1 anaerobic respiration / ethanol fermentation ;\n2 high tolerance to, alcohol / ethanol OR\nhigh / more, alcohol / ethanol, dehydrogenase ;\n\n3(a)(iii) any three from: 3\n1 cross / breed, rice / plants / individuals, with fast-growing stems ;\n2 select / choose, and breed offspring with fast-growing stems ;\n3 repeat (crossing and selection) over generations ;\n4 hybridise / outbreed / out-cross OR\navoid / reduce, inbreeding depression / background selection ;\n\n3(a)(iv) any three from: 3\n1 auxin increases stem, growth / length / height ;\n2 protons / hydrogen ions / H+, move / pumped, into cell wall(s) ;\n3 (expansins) break, links / (H) bonds, between cellulose, molecules / microfibrils ;\n4 water enters cell(s) by osmosis ;\n5 cells, elongate / expand / increase in volume / swell ;\n\n3(b) any three from: 3\n1 O. nivara, adapted to / selected for, dry / drier, conditions / habitats ;\n2 different habitats / ecological isolation ;\n3 prevent interbreeding / no gene flow / reproductive isolation ;\n4 polyploidy / auto(poly)ploidy ;\n5 AVP ;\n© UCLES 2023 Page 10 of 17", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p10.png" ] }, { "id": "9700-2023-mj-41-q04", "question_id": "9700-2023-mj-41-q04", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 11, "status": "available", "reason": null, "text": "4(a)(i) DNA, combined / joined, from, two / different, organisms / sources ; 1\n\n4(a)(ii) any three from: 3\n(protein made in, bacteria / yeast, so)\n1 can be made in, large / unlimited, quantities ;\n2 cheap to make / low cost / cost-efficient ;\n3 does not, harm / involve, animals / pigs / cows ;\n4 no risk of (named) disease, transfer / infection ;\n(sequence identical to human sequence so)\n5 does not cause, allergy / inflammatory response / immune response / antibody production ;\n6 acts more rapidly ;\n7 do not, develop tolerance to it / need larger doses ;\n\n4(b)(i) cow ; 1\n\n4(b)(ii) any three from: 3\n1 obtain (normal human), gene / DNA, from (m)RNA by reverse transcriptase / using restriction enzyme ;\n2 use gene editing (to alter human gene) ;\n3 obtain (nucleotide) sequence for (normal human) insulin gene ;\n4 synthesise, new / analogue, gene / nucleotide sequence ;\n5 put, new / analogue, gene in, bacteria / yeast ;\n6 add promoter for, gene expression / protein synthesis ;\n7 AVP ;\n\n4(c) any three from: 3\n1 can, share / search / access, data(base) / information / sequences ;\n2 from anywhere / online ;\n3 can, compare / align / analyse, (multiple) sequences ;\n4 rapid / fast(er) (process) ;\n5 can, quantify / count, nucleotide differences ;\n6 closely-related species have few, differences / mutations ;\n© UCLES 2023 Page 11 of 17", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p11.png" ] }, { "id": "9700-2023-mj-41-q05", "question_id": "9700-2023-mj-41-q05", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "5(a)(i) A = glomerulus ; 2\nB = Bowman’s capsule ;\n\n5(a)(ii) any four from: 4\n1 ultrafiltration ;\n2 high(er) pressure due to afferent arteriole wider than efferent arteriole ;\n3 capillary endothelium has, fenestrations / gaps / holes / pores ;\n4 small molecules / (named) ions / glucose / amino acids / urea / water, and\nEITHER leave, blood / plasma / capillary / glomerulus\nOR enter, capsule / filtrate / tubule ;\n5 basement membrane forms, (main) filtration / selective, barrier ;\n6 (R)MM / M, limit of, 68 000 to 70 000 (Da) / 68–70 kDa ;\nr\n7 podocytes, form slit pores / support basement membrane ;\n\n5(b)(i) C adenyl(yl) cyclase ; 2\nD c(yclic) AMP ;\n\n5(b)(ii) any four from: 4\n1 in both as Na+ concentration increases ADH concentration increases (after a, certain / stated, point) ;\n2 in, type C / SIAD, ADH rise occurs at a lower Na+ concentration ;\n3 comparative figures ;\n4 (ADH ) more aquaporins / greater permeability to water, in collecting duct / DCT ;\n5 (C / SIAD / ADH ) more water reabsorbed, at collecting duct / at DCT / into blood ;\n6 (C / SIAD / ADH ) small(er) volume of / (more) concentrated, urine ;\n7 type C / SIAD, causes, high blood water potential / low blood Na+ concentration ;\nQuestion Answer Marks", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p12.png" ] }, { "id": "9700-2023-mj-41-q06", "question_id": "9700-2023-mj-41-q06", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 13, "status": "available", "reason": null, "text": "6(a)(i) AAbhbh 2\nAabhbh\nAAbhb\nAabhb ; ;\n© UCLES 2023 Page 12 of 17\n\n6(a)(ii) long, white / albino ; 1\n\n6(b) 1 F1 parent genotypes: AaBb x AaBb ; 5\n2 gametes:\nA A a a A A a a\nB b B b B b B b\n;\n3 F2 offspring genotypes:\nAB Ab aB ab\nAB AABB AABb AaBB AaBb\nAb AABb AAbb AaBb Aabb\naB AaBB AaBb aaBB aaBb\nab AaBb Aabb aaBb aabb ;\n4 evidence of deduction of phenotypes from (min 9 different) genotypes ;\n5 F2 offspring phenotype ratio:\n9 : 3 : 3 : 1\nblack white black white\nshort short long long ;\n© UCLES 2023 Page 13 of 17\n\n6(c)(i) any three from: 3\n1 because they are, on separate chromosomes / not linked ;\n2 each, bivalent / pair of homologous chromosomes, orients itself separately ;\n3 (at equator) in metaphase I of meiosis ;\n4 gives, four / different / new, combinations of alleles / gametes ;\n5 parental allele combinations are not, preserved / fixed ;\n6 AVP ;\n\n6(c)(ii) 1\nphenotype obser\nved expected\n(OE)2\nnumb number (O – E)2\nE\ner (E)\n(O)\nshort, black fur 25 27 4 0.148\nlong, black fur 11 9 4 0.444\nshort, white fur 8 9 1 0.111\nlong, white long 4 3 ; 1 0.333\n\n6(c)(iii) 1.036 ; 1\n© UCLES 2023 Page 14 of 17", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p12.png", "../answer-assets/9700_s23_ms_41-p13.png", "../answer-assets/9700_s23_ms_41-p14.png" ] }, { "id": "9700-2023-mj-41-q07", "question_id": "9700-2023-mj-41-q07", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "7(a) (pyruvate) – serine ; 2\n(oxaloacetate) – asparagine ;\n\n7(b)(i) 1 chloride (ions) / Cl –, not, sodium ions / Na+ (enter post-synaptic neurone) ; 2\n2 glycine not choline (re-enters / recycled to, pre-synaptic neurone)\nOR\nglycine not, broken down / hydrolysed, but acetylcholine is (in synaptic cleft) ;\n\n7(b)(ii) any two from: 2\n1 Cl – decreases, membrane / resting, potential (difference) / voltage ;\n2 harder / need more depolarisation, to reach threshold ;\n3 glycine is inhibitory ;\n\n7(b)(iii) any four from: 4\n1 sodium-potassium pump / active transport ;\n2 Na+, out / leaves and K+, in / enters ;\n3 three Na+ for two K+ ;\n4 some K+ can diffuse out of neurone OR\n(20) more K+ diffuses out than Na+ diffuses in OR\nmembrane is (20) more permeable to K+ (than Na+) ;\n5 inside of, axon / neurone, is more negative (than outside) OR\noutside of, axon / neurone, is more positive (than inside) ;\n© UCLES 2023 Page 15 of 17", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p15.png" ] }, { "id": "9700-2023-mj-41-q08", "question_id": "9700-2023-mj-41-q08", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 4, "status": "available", "reason": null, "text": "8 any four from: 4\n1 DNA / chromatin / chromosomes / chromatids, condense ;\n2 homologous chromosomes, pair up / undergo synapsis / form bivalents / form tetrads ;\n3 crossing-over ;\n4 between non-sister chromatids ;\n5 detail of crossing over ;\n6 chromosomes (stay) joined at, cross-over points / chiasmata ;\nQuestion Answer Marks", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p16.png" ] }, { "id": "9700-2023-mj-41-q09", "question_id": "9700-2023-mj-41-q09", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "9(a) 1 environmental ; 2\n2 discontinuous ;\n\n9(b) any five from: 5\ncoenzyme A:\n1 accepts / binds to / transfers, acetyl (group) ;\n2 acetyl / 2C fragment, + oxaloacetate  citrate ;\n3 (joins) link reaction and Krebs cycle ;\nNAD / FAD:\n4 transfer / transport / carry / accept / reduced by, H+ and e– / H (atoms) / hydrogen (atoms) ;\n5 ref. dehydrogenation (reactions) / dehydrogenase (enzymes) ;\n6 transport, to cristae / to inner mitochondrial membrane / to ETC / for oxidative phosphorylation ;\n7 NAD (accepts H) in glycolysis and link reaction and Krebs cycle ;\n© UCLES 2023 Page 16 of 17", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p16.png" ] }, { "id": "9700-2023-mj-41-q10", "question_id": "9700-2023-mj-41-q10", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 6, "status": "available", "reason": null, "text": "10 any six from: 6\n1 le allele codes for a, non / less, functional enzyme ;\n2 3 beta-hydroxylase ;\n3 alanine replaced with threonine at active site ;\n4 inactive gibberellin / GA20, not converted to, active gibberellin / GA1 ;\n5 no / less, gibberellin to bind to, (intracellular) receptor / GID1 ;\n6 no / less, gibberellin-receptor-DELLA complexes formed ;\n7 DELLA not broken down ;\n8 DELLA (stays) bound to, transcription factors / PIF ;\n9 transcription factor / PIF / RNA polymerase, cannot, bind to promoter ;\n10 growth genes / XET gene, (stay) switched off / not transcribed / not expressed ;\n11 stem does not elongate / internode length is small OR\nno / less, cell division in stem ;\n© UCLES 2023 Page 17 of 17", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_41-p17.png" ] }, { "id": "9700-2023-mj-42-q01", "question_id": "9700-2023-mj-42-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) any one from: 1\nglucose\nis activated / made reactive ;\nbecomes unstable ;\ncannot leave cell ;\nenergy level increased ;\nconcentration gradient maintained ;\n\n1(a)(ii) any one from: 1\ncarrier / acceptor / provider, of, hydrogen (atoms) / electrons\nor\nprovider of H ions and electrons ; R H ions alone\nused for redox reactions ;\nused to reduce, ethanal / pyruvate ;\n\n1(a)(iii) substrate-linked / substrate level ; 1\n© UCLES 2023 Page 7 of 25\n\n1(b) any three from: 3\n1 (inner) mitochondrial membrane impermeable (to pyruvate) ;\n2 carrier (protein) ; A symport / MPC (mitochondrial pyruvate carrier)\n3 lower concentration of pyruvate outside mitochondrion ora\nor\nagainst concentration gradient ;\n4 oxygen available ;\n5 ATP / energy ;\n\n1(c) any three from: 3\n1 decarboxylation ; A description\n2 dehydrogenation / oxidation, (of pyruvate) ; A description\n3 reduced NAD produced ;\n4 formation of, acetyl coenzyme A / acetyl CoA ;\n© UCLES 2023 Page 8 of 25", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p07.png", "../answer-assets/9700_s23_ms_42-p08.png" ] }, { "id": "9700-2023-mj-42-q02", "question_id": "9700-2023-mj-42-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 7, "status": "available", "reason": null, "text": "2(a) haploid is one (complete) set of chromosomes ; 2\ndiploid is two (complete) sets of chromosomes ;\nif only comparative statement = max 1\ne.g. haploid is n chromosomes and diploid is 2n\nhaploid is half the number of chromosomes as diploid / AW\n\n2(b) prophase I 4\nchromosomes / chromatin, condense / shorten / fatten I DNA\nor\nhomologous chromosomes pair up / bivalents form\nor\ncrossing over / synapsis / chiasmata formation ;\nmetaphase I\nhomologous (pairs of) chromosomes / bivalents, line up on the, equator / metaphase plate\nor\nrandom / independent, assortment, of homologous (pairs of) chromosomes / bivalents ;\nanaphase I\nchromosome(s) / one of each pair of chromosomes, moves (to pole / end of cell) ;\ntelophase I\nchromosomes reach the opposite, poles / centrosomes / centrioles / end of cell\nor\nchromosomes decondense / chromatin formation / chromosomes become diffuse ;\n\n2(c) cytokinesis ; 1\n© UCLES 2023 Page 9 of 25", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p09.png" ] }, { "id": "9700-2023-mj-42-q03", "question_id": "9700-2023-mj-42-q03", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 11, "status": "available", "reason": null, "text": "3(a)(i) discontinuous ; 1\n\n3(a)(ii) any two from: 2\n1 mutation A description\nor\n(formation of a) new allele ;\n2 change in, environment / selection pressure ; A description\n3 cross pollination / cross breeding / hybridisation ;\n4 new allele combination / codominant alleles together ;\n\n3(a)(iii) any three from: 3\nboth types\n1 (inter)breed to produce fertile offspring / not reproductively isolated ;\n2 occupy the same niche ;\n3 same / similar, morphology / physiology / biochemistry ;\nA description I fruit shape\n4 have, similar / same, genes / DNA sequences / genomes ;\n5 similar / same, proteins / amino acid sequences ;\n© UCLES 2023 Page 10 of 25\n\n3(b) any five from: 5\n1 (populations) can produce many offspring / AW ;\n2 genetic variation occurs (in populations) / described ;\n3 ref. mutations / sexual reproduction / gamete formation / random fertilisation ;\n4 ref. competition qualified ; e.g. mates / food / resources\n5 ref. selection pressure ;\n6 some individuals have advantageous, adaptations / phenotype / traits / AW ;\n7 (so) they, survive / reproduce / have a selective advantage ;\n8 (so) pass on their advantageous allele(s) ;\n9 (so) the (advantageous) allele frequency increases ;\n© UCLES 2023 Page 11 of 25", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p10.png", "../answer-assets/9700_s23_ms_42-p11.png" ] }, { "id": "9700-2023-mj-42-q04", "question_id": "9700-2023-mj-42-q04", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "4(a) Bacteria and Archaea ; 1\n\n4(b) any four from: 4\n1 obtain (specific restriction endonuclease) gene, qualified ;\ne.g. gene extracted from the, DNA / genome, of E. coli / bacteria\ngene synthesised from the mRNA of E. coli / bacteria\ngene synthesised from nucleotides\n2 PCR to make more copies of, gene / DNA ;\n3 cut a plasmid, with a restriction enzyme / to give sticky ends ;\n4 combine / mix / join, gene with plasmid using ligase ;\n5 add plasmid to, E. coli / bacteria ; A transformation of E. coli\n6 use marker genes to, select / identify, bacteria / E. coli, with recombinant plasmids ;\n7 ref. culture bacteria / use fermenter ;\n8 ref. extraction / purification (of enzyme) ;\n9 AVP ; e.g. heat shock / calcium ions / electroporation (detail mp5)\ncomplementary sticky ends anneal / make phosphodiester bonds (detail mp4)\n© UCLES 2023 Page 12 of 25\n\n4(c) any three from: 3\n1 (data stored is) a large amount of, amino acid / nucleotide / base / DNA, sequences ;\n2 share data / access data quickly ;\n3 compare (amino acid / nucleotide / base / DNA) sequences ;\n4 use to, predict / visualise / model, the structure of the enzyme ;\n5 identify restriction endonuclease to use\nor\nfind / discover, new restriction endonucleases ;\n© UCLES 2023 Page 13 of 25\n\n4(d) any four from: 4\nfeature electrophoresis chromatography\n1 separation role both – are separating techniques\nor\nboth – involve movement of substances ;\n2 molecule separated DNA / RNA / proteins pigments / named\npigment / amino acids ;\n3 medium gel / named gel paper / glass / silica\ngel / named medium ;\n4 separated by (electric) solvent / named solvent\ncurrent / electric\nfield / electricity ;\n5 separated due to charges / polarity / solubilities / mass\nlengths / mass\nboth – separate by mass ;\n6 visualisation using dyes / different colours of\nethidium bromide / pigments / dyes not added /\nUV light UV light not used\nboth - dyes can be added (if TLC) ;\n7 identification by use, DNA use R value\nf\nladder / known length\nof DNA\nor\nuse of DNA probe\n;\nboth - use of, references / known values\n© UCLES 2023 Page 14 of 25", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p12.png", "../answer-assets/9700_s23_ms_42-p13.png", "../answer-assets/9700_s23_ms_42-p14.png" ] }, { "id": "9700-2023-mj-42-q05", "question_id": "9700-2023-mj-42-q05", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "5(a)(i) q2 = 0.6 3\nor\nq = √ 0.6\nor\nq = 0.775\nor\np = 0.225 ;\n2pq = 2  0.225  0.775 or 0.35 ; allow ecf from mp1\n35 % ; allow ecf from mp2\n\n5(a)(ii) any four from: 4\n1 no migration\nor\nno flow of, alleles / genes, into / out of, the population ;\n2 population is isolated / described ; e.g. separated by geographical barrier\nI ref to island alone\n3 random mating is occurring ;\n4 rats move around island / AW ;\n5 large population ;\n6 rats have high reproductive rate / no predators ;\n7 rats are diploid ;\n8 have two different alleles (for the gene) / heterozygous ;\n© UCLES 2023 Page 15 of 25\n\n5(b) any three from: 3\n1 new allele initially found in heterozygotes ;\ndominant advantageous allele\n2 (new) dominant allele is, expressed in heterozygote / always expressed ;\n3 selection can act on individuals with dominant allele straight away / AW ;\nrecessive advantageous allele\n4 (new) recessive allele is not expressed, in heterozygote / due to dominant allele\nor\nrecessive allele only expressed in homozygous recessive (genotype) ;\n5 selection can only act on individuals who are homozygous recessive ;\n6 it takes time for homozygous recessive (genotype) to occur / AW ;\n© UCLES 2023 Page 16 of 25", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p15.png", "../answer-assets/9700_s23_ms_42-p16.png" ] }, { "id": "9700-2023-mj-42-q06", "question_id": "9700-2023-mj-42-q06", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 15, "status": "available", "reason": null, "text": "6(a) 2\nF\nP\n\n6(b)(i) 11852 11852 11852 3\nor or ;\n60 69 51\n1.1 or 1.0 or 1.3 ;\ncm3 min–1 y–1 ; A cm3 min–1 / year\nA year(s) –1\nR yr or yrs or mins\n© UCLES 2023 Page 17 of 25\n\n6(b)(ii) any three from: 3\n1 high(er), hydrostatic / blood, pressure causes higher GFR ; ora\n2 water / solute, potential gradient between glomerulus and Bowman’s capsule affects GFR ;\n3 kidney disease / named, decreases GFR ;\ne.g. damage to nephron or basement membrane / cancer\n4 dehydration / lower water potential of blood, decreases GFR ; ora\n5 high altitude decreases GFR ; ora\n6 drugs / named, affects GFR ;\ne.g. diuretics / beta blockers / vasodilators / NSAIDS / ACE inhibitors\n7 larger difference between afferent arteriole lumen and efferent causes higher GFR ; ora\n© UCLES 2023 Page 18 of 25\n\n6(c) any seven from: 7\n1 Na+, actively transported / pumped, out of cells ;\n2 Na+ enter blood ;\n3 Na+ concentration in cells decreases\nor\nNa+ concentration gradient (between pct lumen and cytoplasm) / described ;\n4 Na+ enter cells from, filtrate / lumen ;\n5 by facilitated diffusion ;\n6 cotransport of, glucose / amino acids ; I secondary active transport\n7 water potential of cells decreases ;\n8 water enters cells from (filtrate / lumen) by, osmosis / down the water potential gradient ;\n9 glucose / amino acids, leave cells by, (facilitated) diffusion / described ;\n10 glucose / amino acids, reabsorbed or move into , tissue fluid / blood ;\n11 AVP ; e.g. other named ions reabsorbed\n© UCLES 2023 Page 19 of 25", "source_pages": [ 17, 18, 19 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p17.png", "../answer-assets/9700_s23_ms_42-p18.png", "../answer-assets/9700_s23_ms_42-p19.png" ] }, { "id": "9700-2023-mj-42-q07", "question_id": "9700-2023-mj-42-q07", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 respiration rate decreases / less ATP produced ;\n2 reduces activity of (named) enzymes / description ;\n3 reduces movement of, Ca2+ / Na+ / ACh / neurotransmitter ;\n4 (in neuromuscular junction)\nless / no, acetylcholine broken down\nacetylcholine remains attached to receptors\nacetylcholinesterase, less active / inactive ;\n5 (in sarcomere)\nfewer / no, Ca2+ bind to troponin\nfewer / no, cross bridges formed\nfewer / no, power stokes ;\n6 (in sarcomere)\nless / no, detachment of myosin heads (from actin)\nfewer / no, cross bridges broken\nATPase / myosin head, less active / inactive\nhydrolysis of ATP, slower / stops ;\n7 AVP ; e.g. shivering / reduced blood flow to muscle / energy diverted for thermoregulation (idea)\n© UCLES 2023 Page 20 of 25\n\n7(b) any three from: 3\n1 Na+ channels don’t open A Na+ do not, diffuse / move, into neurone\nor\nstay open ; A Na+ always, diffuse / move, into neurone\n2 (axon) membrane, cannot be depolarised\nor\n(axon) membrane stays depolarised ;\n3 no action potentials, generated / transmitted (along motor neurone)\nor\ncontinuous action potentials, generated / transmitted (along motor neurone) ;\n4 Ca2+ does not enter presynaptic knob / vesicles not stimulated to move / no ACh release (at neuromuscular junction)\nor\nCa2+ always enters presynaptic knob / vesicles always stimulated to move / ACh continually released (at\nneuromuscular junction) ;\n5 consequence e.g. paralysis / described\nor\ncontinued muscle contraction ;\n© UCLES 2023 Page 21 of 25", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p20.png", "../answer-assets/9700_s23_ms_42-p21.png" ] }, { "id": "9700-2023-mj-42-q08", "question_id": "9700-2023-mj-42-q08", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "8(a)(i) any two from: 3\n1 higher rate of activity (of rubisco) in GM rice (throughout) ;\n2 (low CO concentrations) rate of activity for both increases ;\n2\n3 comparative figures – GM and non-GM at one CO concentration ;\n2\natmospheric CO rate of activity of rubisco / arbitrary units\n2\nconcentration\n/ mg dm–3 non-GM rice GM-rice\n5 0.05 0.05\n0 0.7 0.80\n100 1.8 2.70\n200 2.4 3.95\n280 2.6 4.15\n300 2.6 4.15\n400 2.6 4.30\n500 2.6 4.45\n600 2.6 4.55\n© UCLES 2023 Page 22 of 25\n\n8(a)(i) plus\nlevels off because:\n4 carbon dioxide concentration no longer limiting\nor\nlight intensity limiting\nor\ntemperature limiting\nor\nrubisco active sites saturated (with carbon dioxide)\nor\nless RuBP available ;\n\n8(a)(ii) active site ; A allosteric site 1\n\n8(b)(i) carbon (dioxide) fixation ; A carboxylation 1\n\n8(b)(ii) reduction / hydrogenation ; 1\n\n8(b)(iii) 6 / 5 ; 1\n\n8(b)(iv) any two from: list rule 2\n1 hexose / named ; e.g. glucose / fructose\n2 disaccharide / named ; e.g. sucrose / maltose\n3 starch / cellulose ;\n4 amino acids ;\n5 glycerol / fatty acids ;\n© UCLES 2023 Page 23 of 25", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p22.png", "../answer-assets/9700_s23_ms_42-p23.png" ] }, { "id": "9700-2023-mj-42-q09", "question_id": "9700-2023-mj-42-q09", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 10, "status": "available", "reason": null, "text": "9(a) glands ; 6\ncell surface membrane / plasma membrane ; A liver (cells)\nsecond messenger / cAMP ; A enzyme cascade / phosphorylation of enzymes / signalling cascade\n(striated) muscles ;\ncollecting duct ;\nhomeostasis ;\n\n9(b)(i) 1 insulin, produced / released ; 3\n2 increase in uptake of glucose into cells ;\n3 detail of uptake ; e.g. increase permeability of cell surface membrane (to glucose) / GLUT added to cell surface\nmembrane\n4 increase / stimulates, respiration of glucose (in cells) / phosphorylation of glucose ;\n5 (stimulates) glycogenesis / conversion of glucose to lipids ;\n\n9(b)(ii) ref. glucagon ; 1\n© UCLES 2023 Page 24 of 25", "source_pages": [ 24 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p24.png" ] }, { "id": "9700-2023-mj-42-q10", "question_id": "9700-2023-mj-42-q10", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 10, "status": "available", "reason": null, "text": "10(a) any three from: 3\n1 safe location\nor\nprotected from, predators / hunters / poachers ;\n2 research qualified ; e.g. disease control / into diet / behaviour\n3 raise funds ;\n4 work with local, communities / governments or conservation projects ;\n5 education / raise awareness ;\n6 medical / veterinary / health, (care) ;\n\n10(b) any four from: 4\n1 unnatural environment / described ; ora\n2 effect of captivity on fertility ;\n3 refuses to mate ;\n4 low availability of suitable mates / AW ; ora\n5 stress / pressure ;\n6 AVP ; e.g. zoo capacity / zoos control number they breed\n\n10(c) A – fertilisation occurs / sperm or semen added ; 3\nB and C – surrogacy / described ;\ncryopreservation / described ;\n© UCLES 2023 Page 25 of 25", "source_pages": [ 25 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_42-p25.png" ] }, { "id": "9700-2023-mj-43-q01", "question_id": "9700-2023-mj-43-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "1(a) P – citrate A citric acid 3\nQ – NAD / NAD+\nR – reduced NAD / NADH A NADH\n2\nS – carbon dioxide / CO\n2\nT – FAD\nU – reduced FAD / FADH ;;;\n2\n6 correct = 3 marks\n5/4 correct = 2 marks\n3/2 correct = 1 mark\n\n1(b) any two from: 2\n1 transfer of phosphate group to ADP / ADP phosphorylated / ADP + P → ATP ;\ni\n2 substrate-linked phosphorylation ;\nA substrate-level phosphorylation\nR if oxidative phosphorylation\n3 enzyme (catalysed reaction) ;\n© UCLES 2023 Page 6 of 24\n\n1(c) any four from: 4\n1 small / water-soluble, so can move around cell ;\n2 loss of phosphate / hydrolysis, leads to energy release ;\n3 (release energy) immediately / in small packets\nor\nref. 30.5 kJ (mol–1) ;\n4 can be, recycled / regenerated\nor\nATP ⇆ ADP + Pi ;\n5 link between energy-yielding and energy-requiring reactions / AW ;\n6 high turnover / described ;\n7 ref to ATPase ;\n© UCLES 2023 Page 7 of 24", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p06.png", "../answer-assets/9700_s23_ms_43-p07.png" ] }, { "id": "9700-2023-mj-43-q02", "question_id": "9700-2023-mj-43-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 7, "status": "available", "reason": null, "text": "2 any seven from: 7\n1 (random) mutation ;\n2 directional selection ;\n3 antibiotic acts as selection pressure / AW ;\n4 bacteria with, mutation / gene / allele, (that codes for antibiotic resistance), have selective advantage ;\n5 (so) survive / reproduce ;\n6 ref. binary fission / asexual reproduction / vertical transmission ;\n7 ref. transduction / transformation / conjugation / horizontal transmission ;\nI sexual reproduction\n8 (resistance) allele frequency increases / gives rise to a population of resistant bacteria ;\n9 fast (evolution) due to short generation time ;\n10 increased chance of resistance if people do not finish full course of antibiotics / overuse of antibiotics ;\n11 AVP ; e.g. some antibiotics may act as mutagens\ne.g. enzymes that break down the antibiotic\n© UCLES 2023 Page 8 of 24", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p08.png" ] }, { "id": "9700-2023-mj-43-q03", "question_id": "9700-2023-mj-43-q03", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "3(a)(i) the operon has: 3\npromoter ;\noperator ;\nthree structural genes / named three structural genes ;\nlacZ or  galactosidase gene\nlacA or lactose /  galactoside, permease gene\nlacY or transacetylase gene\nI regulatory genes / order of named parts\n\n3(a)(ii) any four from: 4\nlacI gene\n1 is always expressed ;\n2 controls (structural) gene expression ;\n3 codes for the repressor (protein) ;\n4 repressor, binds to the operator / blocks the promoter ;\n5 prevents, (structural) gene expression / RNA polymerase binding to promoter ;\n6 lactose / allolactose, binds to repressor ;\n7 (so) repressor cannot bind to operator / promoter unblocked / gene expression can occur ;\n© UCLES 2023 Page 9 of 24\n\n3(b) 1 enzymes / proteins, made continuously / all the time ; 3\n2 (because) enzymes / proteins, needed / necessary (for cell) ;\n3 end product inhibition / made until product concentrations too high ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p09.png", "../answer-assets/9700_s23_ms_43-p10.png" ] }, { "id": "9700-2023-mj-43-q04", "question_id": "9700-2023-mj-43-q04", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a) any three from: 3\n1 donor not needed ;\n2 immediate effect ;\n3 idea that easy to administer treatment ;\n4 no immune response / no rejection ;\n5 less invasive ;\n6 AVP ; e.g. lower risk to health / cheaper / quicker\n© UCLES 2023 Page 10 of 24\n\n4(b) any four from: 4\n1 given a drug to increase number of stem cells (in bone marrow) ;\n2 ref. to virus / vector, containing, normal / healthy, allele ;\n3 remove, bone marrow / stem cells ;\n4 mix stem cells with, viral / vector (to allow transfer of normal allele) ;\n5 radiotherapy / drug, to make space in bone marrow / to kill stem cells (in bone marrow) ;\n6 (transduced stem) cells, infused / injected, into blood ;\n7 (lymphocytes) produce functioning ADA ;\n8 AVP ; e.g. (gamma) retrovirus / adeno-associated virus\ne.g. tissue from bone marrow, purified / sorted, to obtain stem cells\ne.g. cells are grown in culture to check the ADA gene is active\n© UCLES 2023 Page 11 of 24\n\n4(c) any three from: 3\n1 expensive ;\n2 cure / long term treatment / no longer chronically ill / better quality of life ;\n3 no need for regular, injections / treatments\nor\nonly a single treatment ;\n4 cultural / religious, objections ;\n5 no donor needed ;\n6 ref. more money available to health system in the long term ;\n7 may cause cancer ;\n8 stressful ;\n© UCLES 2023 Page 12 of 24", "source_pages": [ 10, 11, 12 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p10.png", "../answer-assets/9700_s23_ms_43-p11.png", "../answer-assets/9700_s23_ms_43-p12.png" ] }, { "id": "9700-2023-mj-43-q05", "question_id": "9700-2023-mj-43-q05", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 13, "status": "available", "reason": null, "text": "5(a) 3\n(OE)2\nphenotype observed expected O – E (O – E)2\nE\nred with black spots 279 281.25 –2.25 5.0625 0.018\nwhite with black spots 95 93.75 1.25 1.5625 0.017\nred 96 93.75 2.25 5.0625 0.054\nwhite 30 31.25 –1.25 ; 1.5625 ; 0.05(0)\n0.139 /\n0.14 ;\none mark for each column\n\n5(b) any two from: 2\naccept null hypothesis (no mark)\n1 2 value / 0.139 / 0.14, is lower than, the critical value / 7.815 ;\n2 the observed numbers are not significantly different to the expected numbers\n(at p = 0.05) ;\n3 any differences are due to chance ;\nallow ecf from 5(a)\n© UCLES 2023 Page 13 of 24\n\n5(c) 4\nfemale gametes\nmale\nXRB XrB XRb Xrb\ngametes\nXRXrBB XrXrBB XRXrBb XrXrBb\nfemale female female female\nXrB\nred + black white + black red + black white + black\nspots spots spots spots\nXRYRBB XrYRBB XRYRBb XrYRBb\nmale male male male\nYRB\nred + black red + black red + black red + black\nspots spots spots spots\nXRXrBb XrXrBb XRXrbb XrXrbb\nfemale female female female\nXrb\nred + black white + black white + no\nred + no spots\nspots spots spots\nXRYRBb XrYRBb XRYRbb XrYRbb\nmale male male male\nYRb\nred + black red + black\nred + no spots red + no spots\nspots spots\n;;;;\n© UCLES 2023 Page 14 of 24\n\n5(d) mark as pairs 2\n1 allele R / dominant red allele, is on Y chromosome ;\n2 (so all) males inherit, dominant red allele / allele R\nor\nonly YR is present in the gametes ;\n3 no, allele r / recessive white allele, on Y chromosome\nor\nallele r only exists on the X chromosome ;\n4 (so) males never inherit, recessive white allele / allele r ;\n\n5(e) any two from: 2\n1 mutation ;\n2 detail of mutation ;\n3 crossing over ;\n4 (of) the R allele / dominant red allele, from a Y chromosome to an X chromosome ;\nQuestion Answer Marks", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p13.png", "../answer-assets/9700_s23_ms_43-p14.png", "../answer-assets/9700_s23_ms_43-p15.png" ] }, { "id": "9700-2023-mj-43-q06", "question_id": "9700-2023-mj-43-q06", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 14, "status": "available", "reason": null, "text": "6(a) A – endothelial cell ; 3\nB – basement membrane ;\nC – podocyte ;\n© UCLES 2023 Page 15 of 24\n\n6(b) any two from: 2\n1 acts as the filter ;\n2 prevents molecules more than 68 000 – 70 000 MM from passing through ; ora\n3 stops, large (plasma) proteins / red blood cells ;\n\n6(c) 1801.4 2\n 100\n180\nor\n178.6\n 100 ;\n180\n99.2 ;\n© UCLES 2023 Page 16 of 24\n\n6(d) any seven from: 7\n1 ADH, acts as / is, a cell signalling molecule ;\n2 ADH binds to receptors ;\n3 on cell surface membrane (of collecting duct cells) ; I activates G protein\n4 cAMP / second messenger, produced ;\n5 enzyme cascade / activation of kinase ;\n6 vesicles / aquaporins, phosphorylated / activated ;\n7 vesicles (with aquaporins) move towards cell surface membrane ;\n8 aquaporins added to (cell surface) membrane ;\n9 increases, cell / membrane, permeability to water ;\n10 water moves out (of collecting duct), by osmosis / description ;\n11 into, (collecting duct) cells / tissue fluid / blood ;\nI water is reabsorbed as in Q\n© UCLES 2023 Page 17 of 24", "source_pages": [ 15, 16, 17 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p15.png", "../answer-assets/9700_s23_ms_43-p16.png", "../answer-assets/9700_s23_ms_43-p17.png" ] }, { "id": "9700-2023-mj-43-q07", "question_id": "9700-2023-mj-43-q07", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "7(a) any three from: 4\n1 opens (voltage-gated) Ca2+ channels in sarcoplasmic reticulum\nor\ncalcium ions leave sarcoplasmic reticulum ;\n2 calcium ions bind to troponin ;\n3 troponin changes shape / tropomyosin moves ;\n4 exposes binding site on actin ;\n5 myosin head, binds to (binding) site / forms cross bridge ;\nplus\n6 myosin head, tilts / AW ;\n7 pulls actin / power stroke (so sarcomere shortens) ;\n© UCLES 2023 Page 18 of 24\n\n7(b) any two from: 4\n1 young mice have more (muscle fibres) that are smaller (in diameter) ; ora\n2 young mice have smaller range (of diameters of muscle fibres) ; ora\n3 comparative data quote ; e.g.\nnumber of muscle\nspread of\nfibres at mean\ndiameters / m\ndiameter / m\nyoung mice 35 at 30 16–44\nadult mice 16 at 50 20–80\nplus\nany two from:\nyoung mice\n4 fewer, (muscle) fibres / myofibrils / sarcomeres ; ora\n5 less, muscle protein / actin and myosin ; ora\n6 so, weaker contraction / AW ; ora\n© UCLES 2023 Page 19 of 24", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p18.png", "../answer-assets/9700_s23_ms_43-p19.png" ] }, { "id": "9700-2023-mj-43-q08", "question_id": "9700-2023-mj-43-q08", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "8(a) 4\nletter\nhigh concentration of protons M ;\nlocation of photosynthetic pigments L or N ;\nsite of light-independent stage K ;\nsite of light-dependent stage L or N ;\nignore M in the last row\n\n8(b) any four from: 4\n1 any one named ; e.g. chlorophyll b / carotene / xanthophyll / carotenoids ;\n2 act as accessory pigments / part of antenna complex / part of light harvesting system ;\n3 absorb, light / photons ;\n4 pass energy on to, chlorophyll a / primary pigment / reaction centre ;\n5 absorb different wavelengths of light / wavelengths not absorbed by chlorophyll a ;\n© UCLES 2023 Page 20 of 24\n\n8(c) 1 absorption higher for (whole) chloroplasts (throughout) ; 4\n2 comparative data quote or greatest difference at 525 / 530 nm ;\nabsorbance / au\nwavelength 0.05\n/ nm\nwhole pigment\n500 9.2 6.4\n510 8.4 3.8\n520 7.4 2.3\n525 7.0 1.95\n530 6.6 1.85\n540 6.2 2.05\n550 5.8 2.35\n560 5.8 2.7\n600 6.65 4.7\n650 8.85 8.1\n670 9.6 9.2\n3 (because) pigments arranged for better absorption in chloroplasts / thylakoid membranes are stacked / AW ;\n4 (because) chloroplasts contain more pigments ;\n© UCLES 2023 Page 21 of 24", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p20.png", "../answer-assets/9700_s23_ms_43-p21.png" ] }, { "id": "9700-2023-mj-43-q09", "question_id": "9700-2023-mj-43-q09", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "9(a)(i) any four from: 4\n1 (dopamine) diffuses across synaptic cleft ;\n2 binds to receptors ;\n3 on postsynaptic membrane ;\n4 Na+ channels open R voltage gated channels\nor\ninflux of Na+ into post synaptic neurone ;\n5 depolarisation of postsynaptic membrane ;\n6 ref. threshold ;\n\n9(a)(ii) dopaquinone ; A melanin 1\n\n9(b) any three from: 3\n1 Cl – influx makes (inside of postsynaptic neurone) more negative / stays negative ;\n2 hyperpolarisation / remains polarised ;\n3 (not enough Na+ enter so) less likely to reach threshold ;\n4 no depolarisation of (postsynaptic) membrane ;\n5 (so) no action potential ;\n© UCLES 2023 Page 22 of 24", "source_pages": [ 22 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p22.png" ] }, { "id": "9700-2023-mj-43-q10", "question_id": "9700-2023-mj-43-q10", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "10(a) any four from: 4\nAnimalia Plantae\n1 no cell walls and cell walls ;\n2 no, chlorophyll / chloroplasts and chlorophyll / chloroplasts ;\n3 heterotroph and autotroph / photosynthesis ;\n4 glycogen and starch ;\n5 nervous system and no nervous system ;\n6 move from place to place and unable to move from place to place ;\n7 no, permanent / central, vacuole and permanent / central, vacuole ;\n\n10(b)(i) 0.860.28 0.58 2\nor ;\n4 4\n0.15 ;\nor\n0.850.28 0.57\nor ;\n4 4\n0.14 ;\nAllow ecf if divided by 5 and equals 0.12\n© UCLES 2023 Page 23 of 24\n\n10(b)(ii) any three from: 3\n1 climate change / described ;\n2 less food / less watermilfoil ;\n3 less, snow / cover, so more predation ;\n4 more hunting ;\n5 increased competition ;\n6 loss of habitat / deforestation ;\n7 (new) disease ;\n© UCLES 2023 Page 24 of 24", "source_pages": [ 23, 24 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_43-p23.png", "../answer-assets/9700_s23_ms_43-p24.png" ] }, { "id": "9700-2023-mj-51-q01", "question_id": "9700-2023-mj-51-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a) any one from: 1\nvolume of (pH7) buffer ;\nspeed of centrifuge ;\ntime in centrifuge ;\n\n1(b) idea that time for disc rising decreases as catalase activity increases ; ora 1\n\n1(c)(i) distance from base of shoot ; 1\n\n1(c)(ii) any six from: 6\n1 method to cut, tissue from carrot (root) ;\n2 minimum of 5 distances chosen (or stated distances) ;\n3 same / stated, mass / volume, of cut carrot (used to make the extract) ;\n4 mix / stir, liquid carrot extract (before dipping filter paper discs) ;\n5 method of maintaining temperature (10°C – 40°C if stated) ;\n6 same / stated, height / depth / (stated) volume, of hydrogen peroxide (solution) ;\n7 measure / note / record, the time the filter paper disc takes to rise to the surface (of hydrogen peroxide solution) ;\n8 use at least three measurements for each distance and calculate a mean ;\n9 safety: hazard and risk and mitigation ;\n10 carrying out a control with disc, dipped / AW, in water / buffer (to show rise of the discs is due to the carrot extract) ;\n\n1(d)(i) volume of gas collected (after 1 minute) ; 1\n© UCLES 2023 Page 8 of 12\n\n1(d)(ii) distilled water / deionised water / water, in table heading ; 2\ncorrect volumes of stock solution and water (in Table 1.1) ;\n\n1(d)(iii) supports conclusions: 3\n1 paired data quotes / manipulated data (from Fig. 1.7), to show increase in hydrogen peroxide concentration increases\nthe volume of gas collected ;\ndoesn’t support – max 2 marks:\n2 idea that range (of hydrogen peroxide concentrations) is limited ;\n3 idea that graph has not, plateaued / reached a maximum / AW, so we do not know the value of V ;\nmax\n4 idea that gas collected might not be only oxygen ;\n5 no replicates / no repeats of investigation / no mean calculated ;\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_51-p08.png", "../answer-assets/9700_s23_ms_51-p09.png" ] }, { "id": "9700-2023-mj-51-q02", "question_id": "9700-2023-mj-51-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "2(a) 1 idea of: 3\nadd lice to container and counting lice (on trout) at death\nor\nadd lice to trout (in a container) and counting lice (on trout) at death\nor\ncapture trout with lice attached and count lice (on trout) at death\nor\ntrout(s) with (known) different number of lice attached (in separate containers) and see which die ;\n2 idea of repeat with container (of trout) / trout (in a container) with no lice present ;\n3 named environmental condition in container maintained as constant (for, experimental / control / both, conditions)\nor\nnamed feature of trout / lice maintained as constant (for, experimental / control / both, conditions) ;\n© UCLES 2023 Page 9 of 12\n\n2(b)(i) any one from: 1\nlocation of, boat / sampling site ;\n(electric) current ;\ntime of year ;\n\n2(b)(ii) any one from: 1\nidea that young / small, trout will not be caught / AW ; ora\nidea that there will be more lice on the fish, caught / AW (as they are older / larger) ; ora\n\n2(c)(i) allows for valid comparison; 2\n(because) number (of sea trout), sampled / AW, varies ;\n\n2(c)(ii) paired data quote / manipulated data (to show year 1 to 2 increase) ; 1\nData quotes:\nmean % with \nyear\n13 attached lice\n1 2.6\n2 14.9\nmore / higher 12.3\ntimes increased x5.7\n© UCLES 2023 Page 10 of 12\n\n2(c)(iii) any two from: 2\n1 no difference between year 1 and year 2 of production cycle in 2004–2005 ;\n2 number of sea trout sampled was small ;\n3 (data from) only, 5 production cycles / 10 years ;\n4 no statistical test carried out ;\n\n2(d)(i) there is no, relationship / correlation, between the number of lice (on trout) and the distance from the (nearest) fish farm ; 1\n\n2(d)(ii) (Ireland) significant / yes /  / AW 1\nand\n(Scotland) not significant / no /  / AW ;\n\n2(d)(iii) there is a negative correlation 1\nor\nas distance from (nearest) fish farm increases, (mean) number of lice (per trout) decreases ; ora\n© UCLES 2023 Page 11 of 12\n\n2(d)(iv) Max one from MP1–3 reasons for 95% CI: 2\n1 95%, probability / confidence that / chance that, the, true / actual / population / parametric, mean lies within, this\nrange / these limits\nor\n2 to test whether the means (for number lice per trout at different distances from fish farms) are (significantly) different\nor\nto see / test, whether the, error bars / 95% CI / they, overlap\nor\n3 to get a measure of how close the, calculated / AW, mean is likely to be to the, true / AW, mean\nor\nshorter, error bars / 95% CI, show true mean is likely to be closer to the calculated mean\nor\nlonger, error bars / 95% CI, show true mean is likely to be further from the calculated mean ;\nOne mark for exemplification:\nExemplification of MP 2 or 3 from Fig. 2.3:\nMP2 Exemplification:\nidea that no / less overlap of (95% CI) error bars for Ireland, so (difference), is / may be, significant\nor\nidea that overlap of (95% CI) error bars for, Scotland / Ireland, so (difference), is not / may not be, significant ;\nI direct comparison between Ireland with Scotland\nMP3 Exemplification:\nidea that the, shorter / narrower, error bars for Ireland the closer the calculated mean is (likely to be) to the true mean\nor\nidea that the, larger / longer, error bars for Scotland, the further the calculated mean is (likely to be) from the true mean\nor\nshorter / narrower, error bars / confidence limits, with increasing distance (to nearest fish farm) in, Ireland / Scotland, shows\nthe calculated mean is, getting / AW, closer to the true mean ;\nI direct comparison between Ireland with Scotland\n© UCLES 2023 Page 12 of 12", "source_pages": [ 9, 10, 11, 12 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_51-p09.png", "../answer-assets/9700_s23_ms_51-p10.png", "../answer-assets/9700_s23_ms_51-p11.png", "../answer-assets/9700_s23_ms_51-p12.png" ] }, { "id": "9700-2023-mj-52-q01", "question_id": "9700-2023-mj-52-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 16, "status": "available", "reason": null, "text": "1(a) 1 part enzyme extract/polyphenol oxidase with 9 parts of water / buffer ; 1\n\n1(b)(i) pH ; 1\n\n1(b)(ii) any one from: 1\n1 temperature of, solutions / tubes ;\n2 wavelength of, light / (light) filter (of 470 nm) ;\n3 concentration of enzyme / polyphenol oxidase ;\n4 total length of time /time reading interval ;\n\n1(c)(i) 1 figures from printed line at or below 0.26 au and 30 s 2\nor\nfigures from correct tangent ;\n2 correct calculation / 0.0083 to 0.0089 / 8.3  10–3 to 8.9  10–3 ;\n\n1(c)(ii) sketched line below printed line starting at origin and constantly increasing to 180 s ; 1\n© UCLES 2023 Page 8 of 13\n\n1(d) 1 state at least 5 dilutions (0.0–0.2%) of dopamine hydrochloride solution / substrate ; 7\n2 describe a correct method to making at least 2 dilutions ;\n3 add tubes to a water bath / incubator, at a, set / constant temperature (10–40 °C) ;\n4 enzyme and substrate / (all) solutions equilibrated separately ;\n5 state 2 different variables that are kept constant (volumes of enzyme and substrate or mixture / pH / filter or\nwavelength) ;\n6 set to zero / calibrate, colorimeter using a, blank / water, at the start / between each reading ;\n7 mix substrate and (buffered) enzyme and immediately add (colorimeter tube) to colorimeter ;\nor\nmix substrate and (buffered) enzyme and immediately start timing ;\n8 measure absorbance at set time intervals (for set time) ;\nor\nrecord time at which red colour (first) appears ;\n9 3 replicates / 2 repeats for same / one concentration and calculate a mean\nor\n2 repeats, of experiment / each concentration, and calculate the means ;\n10 calculate / find / work out rate (of reaction) ;\n© UCLES 2023 Page 9 of 13\n\n1(d) 11 named hazard and risk and precaution ;\nHazard Risk Precaution\ndopamine Toxic don’t drink\nhydrochloride don’t pour down the sink\nwear gloves\nIrritant / allergy wear gloves /\ngoggles / mask/ PPE\npolyphenol Irritant / allergy\noxidase / enzyme\nbuffer Irritant / allergy\n12 use water/boiled enzyme instead of enzyme as the control ;\n© UCLES 2023 Page 10 of 13\n\n1(e) 1 enzyme: from different (plant) sources / only from plants / enzyme not used from bananas ; 2\n2 sources of information: maybe out of date / maybe unreliable / not comparable ;\n3 variables: 2 variables not controlled / not standardised / no information (temperatures, pH, timings, volumes,\nconcentrations) ;\n4 stats: no statistical test / analysis ;\n5 substrate: no information, on what substrate was used / whether tested on bananas or other fruits ;\n6 inhibitor: do not know type of inhibition (competitive v. non-competitive) ;\n7 anti-browning agents: idea that other anti-browning agents maybe more or less effective / may impact differently ;\n8 anti-browning agents should be tested on all sources of enzyme / each only tested on one source of enzyme / may act\ndifferently on other sources of enzyme ;\n9 validity: 2 independent variables ;\n\n1(f) sketched line (starts at origin) levels out showing lower Vmax ; 1P\nQuestion Answer Marks", "source_pages": [ 8, 9, 10, 11 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_52-p08.png", "../answer-assets/9700_s23_ms_52-p09.png", "../answer-assets/9700_s23_ms_52-p10.png", "../answer-assets/9700_s23_ms_52-p11.png" ] }, { "id": "9700-2023-mj-52-q02", "question_id": "9700-2023-mj-52-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 14, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\ntype /species of tree / type of bark ;\nheight (of grid) above ground ;\nside / aspect of tree ;\nage / size of tree ;\nAVP grid placed horizontally / orientated as diamond shape ;\n© UCLES 2023 Page 11 of 13\n\n2(a)(ii) 2\nHazard and risk – 1 mark ; Precaution – 1 mark ;\nTrees / plants scratches / allergy / irritation suitable\n/ leaves / bark toxins PPE / medication\n/ pollen don’t ingest\nAnimals dangerous / allergy / bites / to medication / work in a\n/Animal waste xoplasmosis group / travel with an\nexpert /suitable PPE\nFungi / Lichen irritation / allergic reaction suitable PPE\ntoxic / poisonous do not ingest\nInhaling (lung) infection wear a mask\nfungal spores\nTraffic collision / fumes / air pollution cone off the road / hi vis\nvest / look +\nlisten / suitable PPE\nWoods / holes Injury from look where you’re\n/trip hazards trips / falling / falling stepping / hard hat / don’t\nbranches / getting climb trees / GPS / map\nlost / hypodermic needles\n\n2(b) 1 39 / 90 (100) ; 2\n2 43 / 43.3 (%) ;\n\n2(c)(i) D = 2 and D2 = 4 ; 1\n© UCLES 2023 Page 12 of 13\n\n2(c)(ii) 0.760 / 0.759 ; ; 2\nIf answer is incorrect\nallow 1 mark for evidence of correct calculation\n238.5 / 990 or 0.241\n\n2(c)(iii) strong (correlation) ; 3\npositive (correlation) ;\n(showing that) as distance from road increases, cover / abundance of lichen increases / ora ;\n\n2(c)(iv) use critical values (of r ), at p= 0.05 or less ; 2\ns\nif calculated r is greater than critical r value (correlation) is not due to chance\ns s\nor\nif calculated value of r is less than the critical r value (correlation) is due to chance ;\ns s\n© UCLES 2023 Page 13 of 13", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_52-p11.png", "../answer-assets/9700_s23_ms_52-p12.png", "../answer-assets/9700_s23_ms_52-p13.png" ] }, { "id": "9700-2023-mj-53-q01", "question_id": "9700-2023-mj-53-q01", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a) (red to magenta shows) increase in, pH / decrease in, concentration of, carbon dioxide ; 2\n(in the light C. vulgaris) uses up / AW, carbon dioxide for photosynthesis ;\n\n1(b)(i) light intensity ; 1\n\n1(b)(ii) any eight from: 8\n1 use, lamp / AW, at minimum of 5 different distances from plant\nor\nuse, lamp / AW, with minimum 5 different power ratings / wattages (at same distances) ;\n2 use, a light meter / an app, to measure light intensity ;\n3 idea that carry out investigation, in a darkened room / with no other light source ;\n4 same / stated, mass / number / size, of alginate beads ;\n5 same / stated, volume / concentration, of hydrogencarbonate indicator\nor\nsame starting, colour / pH, hydrogencarbonate indicator ;\n6 use a method to reduce heating effect of lamp ;\n7 method to measure, colour / pH, of hydrogencarbonate indicator ;\n8 measure / note / record, the colour/pH (of the indicator) after a, set / stated, time\nor\nmeasure / note / record, the time taken (for the indicator) to be a, set / stated, colour / pH ;\n9 use at least three measurements for each light intensity and calculate a mean ;\n10 safety: hazard and risk and mitigation ;\n© UCLES 2023 Page 8 of 13\n\n1(b)(ii)\nhazard risk mitigation\nhydrogencarbonate irritant / allergy gloves / goggles / mask /\nindicator PPE / medication\nalginate beads / C. irritant / allergy gloves / goggles / mask /\nvulgaris PPE / medication\nheat (from bulb) burns / injury gloves / do not touch\n11 use of a suitable control ;\n\n1(c) will turn orange / yellow or pH decreases ; 2\nrespiration, produces carbon dioxide ;\n\n1(d)(i) correct working ; 2\n229 000 ;\n\n1(d)(ii) 1 correct number of cells counted / 24 ; 3\n2 correct working ;\n3 correct calculation of number of cells per cm3 / 240 000 ;\n© UCLES 2023 Page 9 of 13\n\n1(d)(iii) any two from: 2\nSecchi stick is less accurate:\n1 subjective / difficult to determine when circle is no longer visible ;\n2 error of  0.5 mm in the ruler ;\n3 Secchi stick, not held vertical ;\n4 no replicates / no repeats of investigation / no mean calculated ;\n5 idea that Secchi stick used is, different / AW, from Secchi stick used for calibration curve ;\n6 idea that inserting Secchi stick, mixes / disturbs / AW, suspension ;\n© UCLES 2023 Page 10 of 13", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_53-p08.png", "../answer-assets/9700_s23_ms_53-p09.png", "../answer-assets/9700_s23_ms_53-p10.png" ] }, { "id": "9700-2023-mj-53-q02", "question_id": "9700-2023-mj-53-q02", "subject": "9700", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2\nheight (of grids) above ground ;\nside / aspect, of tree ;\nage / size of tree ;\ntype / species, of tree ;\ngrid placed horizontally / orientated as diamond shape ;\n© UCLES 2023 Page 11 of 13\n\n2(a)(ii) named hazard and risk ; 2\nmatching precaution ;\nhazard and risk – 1 mark precaution – 1 mark\nplants – leaves, bark, toxic / scratches / irritant / suitable\npollen allergy PPE / medication / don’t\ningest\nanimals, animal waste dangerous / allergy / bites medication / work in a\n/ toxoplasmosis group / travel with an\nexpert / suitable PPE\nfungi, lichen toxic / irritant / allergy suitable PPE / medication\ninhaling fungal spores (lung) infection wear a mask\nwoods, falling injury / getting lost look where you’re\nbranches / trees, holes, stepping / boots / hard\ntrip hazards hat / don’t climb\ntrees / GPS / map / travel\nwith an expert\nclimbing trees (upper injury (from use a ladder / use\nheight grid) trips / falls / falling ropes / hard\nbranches) hat / training / use an\nexpert\n\n2(b) 63.3( / 100)  90 / 0.633  90 ; 2\n57 (circles) ;\n\n2(c)(i) there is no, difference, in the abundance of (salted shield) lichen between, exclosures and grazed areas ; 1\n© UCLES 2023 Page 12 of 13\n\n2(c)(ii) any one from: 1\n1 no, significant difference, between exclosures and grazed areas, for base of tree ;\nor\nthere is a, significant difference, between exclosures and grazed areas, for middle and upper parts of tree ;\n2 the, percentage cover / abundance, of (salted shield) lichen is greater, as height of grid increases ; ora\n3 percentage cover / abundance, of (salted shied) lichen is greater, in grazed areas (than in exclosures) ; ora\n\n2(c)(iii) any two from: 2\n1 check named abiotic factor is similar (in exclosures and grazed areas) ;\n2 check named biotic factor is similar (in exclosures and grazed areas) ;\n3 repeat the investigation, in other years (after 2013) ;\n© UCLES 2023 Page 13 of 13", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2023-May-June/ms/9700_s23_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-may-june/9700_s23_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s23_ms_53-p11.png", "../answer-assets/9700_s23_ms_53-p12.png", "../answer-assets/9700_s23_ms_53-p13.png" ] }, { "id": "9700-2023-on-41-q01", "question_id": "9700-2023-on-41-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "1(a)(i) thylakoid(s) ; 1\n\n1(a)(ii) any four from: 4\nup to three descriptions (D) and one / two linked functions (F)\nD1 stacked / many (A / thylakoids) / large surface area ;\nF2 to increase light absorption ;\nD3 (thylakoid) membrane has, (named), pigments / photosystems / electron carriers / enzymes ;\nF4 (thylakoid membrane role is) light-dependent reaction / photophosphorylation / creates proton gradient / pump\nprotons / chemiosmosis / makes ATP ;\nD5 (thylakoid) lumen / space ;\nF6 accumulates H+ / high H+ concentration ;\nD7 appear green (under microscope) ;\nF8 as / so, chlorophyll absorbs red and blue light ;\n\n1(b)(i) Calvin (cycle) ; 1\n\n1(b)(ii) any two from: 2\n1 no start and end, point / molecules ;\n2 all, molecules / intermediates, present all the time ;\n3 ribulose bisphosphate / RuBP / 5C molecule, is regenerated ;\n4 numerical detail ;\n\n1(c)(i) B: oxygen ; 2\nD: sugar / hexose / glucose / triose phosphate / carbohydrate / starch ;\n\n1(c)(ii) 1 (oxygen linked to) aerobic respiration / oxidative phosphorylation ; 3\n2 (glucose stated as) source / store, of (chemical) energy / ATP / food ;\n3 ref. to energy flow through, food chains / food web / ecosystem ;\n© UCLES 2023 Page 7 of 16", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p07.png" ] }, { "id": "9700-2023-on-41-q02", "question_id": "9700-2023-on-41-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "2(a) 1 number of / range of (different), ecosystems / habitats ; 2\n2 number of species and their relative abundance ;\n\n2(b) any three from: 3\n1 to, store / contain, multiple / many, genome / DNA / nucleotide, sequences ;\n2 to, align / compare / search, sequences ;\n3 to, process / analyse / sort / calculate from, large quantities of data ;\n4 to, share / access, data / information from, others / elsewhere ;\n5 to save time / fast(er) ;\n\n2(c)(i) Anopheles ; 1\n\n2(c)(ii) three / 3 ; 1\n\n2(d)(i) any three from: 3\n1 less able / not able, to, adapt / evolve ;\n2 little variation for selection to act on ;\n3 few(er) (potentially), useful / beneficial, alleles ;\n4 all / most, (could be) killed by same, disease / selection pressure ;\n5 if due to small population size this decreases species survival chance ;\n\n2(d)(ii) low(er) genetic variation means high(er), conservation status / threat / vulnerability / endangerment / risk of extinction ; 1\n\n2(d)(iii) any three from: 3\ndoes not support because\n1 chimpanzee has, most / highest, genetic variation but is, EN / endangered ;\n2 minke whale has (joint), least / lowest, genetic variation but is, LC / least concern ;\n3 genetic variation, similar / same, but conservation status is different ;\n4 example ;\n5 gorilla is, most / critically, endangered but has high(er) genetic variation ;\n6 AVP ; e.g. ref. to data limited to only seven species\n© UCLES 2023 Page 8 of 16", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p08.png" ] }, { "id": "9700-2023-on-41-q03", "question_id": "9700-2023-on-41-q03", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 16, "status": "available", "reason": null, "text": "3(a) 1 (q2 = 440 or q2 = 0.4 ) 3\n1100\nq = √0.4\nor\nq = 0.632455532 ;\n2 (p = 1 – 0.632455532 or p = 0.367544468)\n2pq = 2 x 0.632455532  0.367544468\nor\n2pq = 0.4649110641 ;\n3 (heterozygotes = 2pq  1100 e.g. 511.4 or 511.5 or 511.6672 )\n511 / 512 ;\n\n3(b) any two from: 2\n1 colours / shades / categories / phenotypes, not distinct / not discrete / overlap / form a (gradual) range / include\nintermediates ;\n2 >1 / 4 / several / many, genes ;\n3 environment affects, it / colour / phenotype ;\n\n3(c)(i) any two from: 2\n1 (as climate changes) increase in CO concentration causes, stomatal aperture to decrease / stomata to be less open ;\n2\n2 less water, lost / evaporated / transpired (though stomata) ;\n3 compensates for / allows survival in, low water availability / dry conditions ;\n© UCLES 2023 Page 9 of 16\n\n3(c)(ii) any four from: 4\n1 (abscisic acid / ABA) binds to receptor on, (guard) cell surface membrane ;\n2 H+ stops moving, out of cell / into cell wall ;\n3 Ca2+ ions enter, cytoplasm / cell\nor\nCa2+ ions act as second messenger ;\n4 K+ ions leave cell ;\n5 water leaves cell, by osmosis / down water potential gradient ;\n6 less turgid / flaccid, guard cell(s) close stoma(ta) ;\n\n3(d)(i) any two from: 3\n1 0.1, (mol) increases / gives higher, rate (compared to control / normal) ;\n2 1(.0) and 10(.0), (mol) decrease / give lower, rate (compared to control / normal) ;\n3 10(.0) (mol) rate, stays (approx.) constant / plateaus / does not increase, over, time / (6) days ;\n4 data quote comparing rate at two concentrations on one day\nor\ndata quote comparing rate on two different days for 10 mol ;\n\n3(d)(ii) 1 protons / H+ (ions) ; 2\n2 cellulose ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p09.png", "../answer-assets/9700_w23_ms_41-p10.png" ] }, { "id": "9700-2023-on-41-q04", "question_id": "9700-2023-on-41-q04", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 7, "status": "available", "reason": null, "text": "4(a)(i) 1 DNA, joined / combined / made, from two / different, sources / species ; 2\n2 using (named), enzymes / vectors or to create a, GMO / transgenic organism ;\n\n4(a)(ii) to, test / compare, effect(iveness) of, genes / proteins / Bt and OCII / plants / varieties / A and B 1\nor\nto see which, (gene / plant / variety / of A and B), works, better / best ;\n\n4(a)(iii) to compare / provide a baseline / as a control ; 1\n© UCLES 2023 Page 10 of 16\n\n4(b) 1 A and B kill larvae ; 3\n2 GM increases, yield of / food from (potatoes) ;\n3 A, is best / kills most / works faster / should be grown / will provide most food ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p10.png", "../answer-assets/9700_w23_ms_41-p11.png" ] }, { "id": "9700-2023-on-41-q05", "question_id": "9700-2023-on-41-q05", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "5(a) highest: malic acid ; 2\nlowest: oleic acid ;\n\n5(b) any five from: 5\nsimilarities:\n1 use pyruvate ;\n2 occur in, cytoplasm / cytosol ;\n3 make / regenerate, NAD ;\n4 redox reaction ;\ndifferences:\n5 lactate / lactic acid, made in mammals and ethanol in yeast ;\n6 one step in mammals and two steps in yeast ;\n7 carbon dioxide made in yeast (not in mammals) ;\n8 reversible in mammals and irreversible in yeast ;\nQuestion Answer Marks", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p11.png" ] }, { "id": "9700-2023-on-41-q06", "question_id": "9700-2023-on-41-q06", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) any two from: 2\n1 transparent phenotype (reappears) in F2 (but not F1) ;\n2 so it is, inherited / passed down / genetic / not environmental ;\n3 new / recessive, allele ;\n\n6(a)(ii) 9 : 3 : 3 : 1 ; 1\n© UCLES 2023 Page 11 of 16\n\n6(a)(iii) any four from: 4\n1 two genes ;\n2 on separate chromosomes / not linked ;\n3 not sex-linked / autosomal ;\n4 each gene has / both genes have, two alleles ;\n5 albino / white stripes, is recessive (allele) ;\n6 transparent / non-gold, is recessive (allele) ;\n7 wild type is dominant for both genes ;\n\n6(b) any four from: 4\n1 homologous chromosomes, pair up / form bivalents ;\n2 at prophase I ;\n3 independent assortment / random orientation\nor\nindependent segregation ;\n4 (happens) at metaphase I\nor\nat anaphase I ;\n5 one chromosome of (each) pair has dominant allele and one has recessive ;\n6 four, combinations / permutations / different gametes ;\n7 worked example / diagram ;\n© UCLES 2023 Page 12 of 16", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p11.png", "../answer-assets/9700_w23_ms_41-p12.png" ] }, { "id": "9700-2023-on-41-q07", "question_id": "9700-2023-on-41-q07", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "7(a)(i) any four from: 4\nboth\n1 acetylcholine, in / from, vesicles ;\n2 many mitochondria ;\n3 have presynaptic and postsynaptic membranes ;\n4 (synaptic) cleft / gap ;\n5 have receptor(s) (for ACh / neurotransmitter) ;\n6 presynaptic, Ca2+, entry / channels\nor\npostsynaptic Na+, entry / channels ;\n\n7(a)(ii) any three from: 3\n1 few(er) Ca2+ ions, leave sarcoplasmic reticulum / enter sarcoplasm ;\n2 few(er) Ca2+ ions bind to troponin ;\n3 few(er) troponin molecules change shape ;\n4 few(er) tropomyosin molecules move ;\n5 few(er) myosin-binding sites, uncovered / exposed ;\n6 few(er), actin-myosin cross bridges form / myosin (heads) bind to actin ;\n7 AVP ; e.g. lack of P leads to less ATP formed\ni\n8 AVP ; e.g. myosin-actin cross-bridges do not break / myosin heads do not reset\n\n7(b) A: adenylyl cyclase ; 2\nB: protein kinase A ;\nQuestion Answer Marks", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p13.png" ] }, { "id": "9700-2023-on-41-q08", "question_id": "9700-2023-on-41-q08", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 6, "status": "available", "reason": null, "text": "8(a) letter X on rising slope to the left of the angle where line plateaus ; 1\n\n8(b)(i) reverse transcriptase ; 1\n\n8(b)(ii) transcription factor(s) ; 1\n© UCLES 2023 Page 13 of 16\n\n8(b)(iii) any three from: 3\n1 in high light intensity plant can photosynthesise more ;\n2 so they need (more) / upregulate / increase / make (more) (named) enzymes / proteins, for photosynthesis ;\n3 (plus) named, enzyme / protein (for photosynthesis) ;\n4 (named) pigments to protect cells from excess light ;\n5 enzymes to make, sucrose / starch / amino acids ;\n6 proteins for, sucrose / amino acid, transport ;\n7/8 AVP ;; e.g. DELLA breaks down releasing, phytochrome interacting factors / PIF\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p13.png", "../answer-assets/9700_w23_ms_41-p14.png" ] }, { "id": "9700-2023-on-41-q09", "question_id": "9700-2023-on-41-q09", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "9(a)(i) any three from: 3\n1 (random) mutation(s) allows detection of high frequency ;\n2 selection pressure is bat (predation) ;\n3 those that can detect, high frequencies / bats, survive / don’t get eaten / have selective advantage / are selected for ;\n4 these, reproduce / pass on (beneficial) allele(s) ;\n5 those that can detect high sounds / beneficial alleles, increase (in frequency / in population) ;\n\n9(a)(ii) any four from: 4\n1 ref. to receptor / generator, potential ;\n2 vesicles of (named) neurotransmitter, move towards / fuse with, (presynaptic) membrane ;\n3 (named) neurotransmitter, release / exocytosis ;\n4 neurotransmitter binds to receptors on sensory neurone ;\n5 Na+ / sodium, ions enter (sensory neurone) ;\n6 depolarisation (of membrane of sensory neurone) ;\n7 ref. to threshold potential / all-or-nothing response ;\n© UCLES 2023 Page 14 of 16\n\n9(b) any three from: 3\nS1 sympatric (speciation) ;\nS2 different mutations ;\nS3 gave, (named) phenotypic / behavioural, differences ;\nS4 which gave behavioural, isolation / separation ;\nS5 (leading to) inability to reproduce together / reproductive isolation / genetic isolation / no gene flow between them ;\nor\nany three from:\nA1 allopatric (speciation) ;\nA2 geographical, separation / barrier, in the past ;\nA3 different, mutations / selection pressures ;\nA4 gave, (named) phenotypic / behavioural, differences ;\nA5 inability to reproduce together / reproductive isolation / genetic isolation / no gene flow between them, after populations\nre-join ;\n© UCLES 2023 Page 15 of 16", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p14.png", "../answer-assets/9700_w23_ms_41-p15.png" ] }, { "id": "9700-2023-on-41-q10", "question_id": "9700-2023-on-41-q10", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 7, "status": "available", "reason": null, "text": "10 any seven from: 7\n1 genetic engineering / recombinant (DNA technology) ;\n2 (named) drug / treatment / protein, from, (GM) bacteria / (GM) yeast / (named) (GM)O ;\n3 make insulin (drug for diabetes) ;\n4 make factor VIII (drug for haemophilia) ;\n5 make adenosine deaminase (drug for SCID) ;\n6 genetic, screening / diagnosis / testing ;\n7 (detect) BRCA1 / BRCA2 ;\n8 (detect number of repeats / allele for) Huntington’s ;\n9 (detect allele for) cystic fibrosis / CFTR ;\n10 example of action if diagnosis positive ;\n11 gene therapy ;\n12 insert / add, normal allele into (named), cells / tissue (of person) ;\n13 to treat, eye disease(s) / LCA / Leber’s congenital amaurosis ;\n14 to treat SCID ;\n15/16 AVP ; ; e.g. ref. to help / develop, xenotransplantation\nGM / antigen-free, pigs / animals, to source, tissues / organs, for transplants\nGM plants to make vaccines\nGM / recombinant / DNA / mRNA, vaccines\nrecombinant antibody technology\nother / different, recombinant therapeutic protein / genetic screening / gene therapy, example\n© UCLES 2023 Page 16 of 16", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_41-p16.png" ] }, { "id": "9700-2023-on-42-q01", "question_id": "9700-2023-on-42-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "1(a) A: carbon dioxide / CO ; 3\n2\nB: reduced NAD / NADH and C: NAD / NAD+ ;\nD: ethanal ;\n\n1(b) any three from: 3\n1 (recycles / produces) NAD ; I ref. to reduced NAD produced ;\n2 ref. to glycolysis ;\n3 ref. to ATP (produced) ;\n4 by substrate-linked phosphorylation ;\n\n1(c) any three from: 3\n1 aerenchyma provides oxygen for aerobic respiration ;\n2 high concentration of ethanol dehydrogenase / high tolerance for ethanol, allows (higher rate of), ethanol\nfermentation / anaerobic respiration ;\n3 fast growth / grow tall, so leaves, out of water / exposed to air ;\n4 AVP ; e.g. ridges in submerged leaves to trap air\nQuestion Answer Marks", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p07.png" ] }, { "id": "9700-2023-on-42-q02", "question_id": "9700-2023-on-42-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 14, "status": "available", "reason": null, "text": "2(a) involve mitosis: 1 / 3 ; 5\ninvolve meiosis: 4 ;\nproduces new genetic variation: 2 / 4 ;\nshows only haploid cells: 1 / 5 ; ignore 2\nshows only diploid cells: 3 ; ignore 2\n© UCLES 2023 Page 7 of 18\n\n2(b) any four from: 4\n1 genetic variation ;\n2 due to, crossing over / independent assortment ;\n3 some will, be adapted (to changing environment) / survive\nor\navoids whole population being wiped out / ora ;\n4 (allows) stage 1 / stage 3 / asexual reproduction ;\n5 (allows) random, mating / fertilisation / fusion of gametes ;\n6 some have advantageous combinations of alleles ;\n7 AVP ; e.g. ref. to dormancy\n\n2(c) any three from: 3\nhaploid\n1 only cell with harmful mutation will, be affected / die ;\n2 rest of population unaffected / AW ;\ndiploid\n3 recessive allele for harmful mutation, will be masked by dominant (normal) allele / not expressed in heterozygote ;\n4 AVP ; e.g. (haploid) removes mutated allele from population\n\n2(d) any two from: 2\n1 eukaryotic (cells) / described ;\n2 heterotrophic / saprotrophic / parasitic / described ;\n3 chitin cell walls ;\n4 (most have) hyphae / mycelium ;\n5 multinucleate (cells) ;\n6 multicellular and unicellular ;\n© UCLES 2023 Page 8 of 18", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p07.png", "../answer-assets/9700_w23_ms_42-p08.png" ] }, { "id": "9700-2023-on-42-q03", "question_id": "9700-2023-on-42-q03", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 7, "status": "available", "reason": null, "text": "3(a) any five from: 5\n1 select plants (resistant to disease) / AW ;\n2 by exposing plants to disease to show resistance ;\n3 breed (selected plants with resistance) ;\n4 plant seeds / grow offspring ;\n5 select offspring with resistance and breed together ;\n6 (repeat for) many generations ;\n7 AVP ; e.g. named wheat disease / rust disease / mildew disease\n\n3(b) any two from: 2\n1 reduction in genetic variation / gene pool made smaller / decrease in heterozygosity / increase in homozygosity ;\nI loss of biodiversity\n2 less hybrid vigour ;\n3 inbreeding depression ;\n4 harmful recessive alleles could, come together / be expressed ;\n5 (population) susceptible to, environmental change / new disease ;\n6 AVP ; e.g. disadvantageous traits occur / reduced fertility / susceptible to metabolic disorders\nQuestion Answer Marks", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p09.png" ] }, { "id": "9700-2023-on-42-q04", "question_id": "9700-2023-on-42-q04", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 marker gene added with gene of interest (GOI) ;\n2 use same promoter ;\n3 (so) both genes, transcribed / expressed (together) ;\n4 (so) both proteins are produced ;\n5 use UV light (to detect fluorescence) ;\n6 fluorescence shows, transcription / expression, of gene of interest (GOI) ;\n7 AVP ; e.g. fluorescent proteins not harmful / have no effect on plant / do not affect quantity of desired protein produced\n© UCLES 2023 Page 9 of 18\n\n4(b) any two from: 2\n1 high / increase in, yield / productivity / quality\nor\nmore food ;\n2 increased income / reduce costs ;\n3 can use herbicides / AW ;\n4 less / no, competition ;\n5 no need to plough / less labour intensive ;\n\n4(c)(i) complementary (base pairing between DNA strands) / described ; 1\n\n4(c)(ii) any two from: 3\n1 use mRNA to make (ss)cDNA ;\n2 fluorescent, tag / dye / substance / label, attached to cDNA ;\n3 hybridisation / binding, of cDNA to probe ;\n4 use, lasers / UV light, to produce fluorescence ;\nplus\n5 idea of intensity of, fluorescence / light, indicates level of (gene) expression ;\n© UCLES 2023 Page 10 of 18", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p09.png", "../answer-assets/9700_w23_ms_42-p10.png" ] }, { "id": "9700-2023-on-42-q05", "question_id": "9700-2023-on-42-q05", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "5(a) all correct (1827) ; 1\nphenotype observed expected\nnumber number\nbrown body colour, straight wings 2843 1827\nbrown body colour, curved wings 855 1827\nblack body colour, straight wings 842 1827\nblack body colour, curved wins 2768 1827\n\n5(b) any four from: 4\n1 ref. to 3 degrees of freedom ;\n2 the, 2 value / 2098, is greater than 7.815 (at p=0.05) ;\n3 there is a significant difference ;\n4 reject the null hypothesis ;\n5 any difference is not due to chance / less than 5% (probability) that difference is due to chance ;\n6 the, 2 value / 2098, is greater than, 11.345 at p=0.01 / 16.266 at p=0.001\nor\nless than, 1% / 0.1% (probability), that difference is due to chance ;\n© UCLES 2023 Page 11 of 18\n\n5(c) any four from: 4\n1 greater numbers of parental phenotypes / fewer numbers of recombinants ;\n2 genes are linked / autosomal linkage / genes are on same chromosome ;\n3 alleles inherited together ;\n4 B inherited with D and b inherited with d\nor\nB and D in the same gamete and b and d in the same gamete ;\n5 no independent assortment ;\n6 crossing over (produces recombinants) ;\n7 during, meiosis / prophase I / gamete formation ;\n8 AVP ; e.g. idea that genes are far enough apart on chromosome for recombination to occur\nQuestion Answer Marks", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p11.png", "../answer-assets/9700_w23_ms_42-p12.png" ] }, { "id": "9700-2023-on-42-q06", "question_id": "9700-2023-on-42-q06", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 14, "status": "available", "reason": null, "text": "6(a)(i) P: receptor ; 4\nQ: adenyl(yl) cyclase ;\nR: G-protein ;\nS: cyclic AMP / cAMP ;\n© UCLES 2023 Page 12 of 18\n\n6(a)(ii) 3\nprocess effect on rate of process when\nblood glucose concentration\ndecreases\nglycogenolysis increase\nglycogenesis decrease\nglycolysis decrease\nfatty acid synthesis decrease ;;;\n4 correct = 3 marks\n3 correct = 2 marks\n1/2 correct = 1 mark\n\n6(b) any four from: 7\n1 strip contains glucose oxidase and peroxidase ;\n2 strip dipped into urine ;\n3 glucose (and oxygen) reacts with glucose oxidase to produce hydrogen peroxide ;\n4 hydrogen peroxide reacts with peroxidase to produce a colour change ;\n5 colour is matched with a colour chart to give, reading / estimate, of glucose concentration ;\nany three from:\n6 quick(er) ;\n7 (more) sensitive / accurate / precise ;\n8 gives immediate reading ;\n9 results can be stored electronically / can be connected to smart phone / AW ;\n10 numerical / digital / quantitative / objective ;\n11 reusable ;\n© UCLES 2023 Page 13 of 18", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p12.png", "../answer-assets/9700_w23_ms_42-p13.png" ] }, { "id": "9700-2023-on-42-q07", "question_id": "9700-2023-on-42-q07", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 mitochondria produce ATP ;\npresynaptic knob\n2 for production of, acetylcholine / ACh ;\n3 for, making / moving, vesicles ; A exocytosis\nsarcomere\n4 active transport of Ca2+ into, sarcoplasmic reticulum ;\n5 detachment of myosin heads / break cross bridge\nor\nallows myosin head to move back to original position ;\n6 AVP ; e.g. ref. to sodium potassium pump / active transport of Ca2+ out of synaptic knob\n\n7(b) X – agree, because Na+ influx leads to depolarisation ; 3\nY – disagree, because Cl– influx leads to hyperpolarisation / description\nor\ndisagree, because no Na+ influx so no depolarisation ;\nX and Y – agree, because Na+ (influx) is balanced by Cl– (influx) / AW ;\n\n7(c) any two from: 2\n1 decrease in transmission speed ;\n2 ref. to shorter local circuits ;\n3 no / less, saltatory conduction / described ;\n© UCLES 2023 Page 14 of 18", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p14.png" ] }, { "id": "9700-2023-on-42-q08", "question_id": "9700-2023-on-42-q08", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "8(a) any four from: 4\n1 both photosystem I and photosystem II involved ; A both photosystems\n2 photoactivation of chlorophyll occurs ;\n3 photolysis of water occurs / description ;\n4 oxygen production / oxygen-evolving complex involved ;\n5 electrons emitted by photosystem I used to reduce NADP\nor\nNADP is the final electron acceptor ;\n6 photosystem I receives electrons from photosystem II\nor\nphotosystem II receives electrons from photolysis (of water) ;\n7 ETC / electron transport chain, sets up proton gradient\nor\nchemiosmosis / ATP produced ;\n\n8(b) GP used to make, amino acids / fatty acids / lipids ; 2\nTP used to make, hexose / starch / cellulose / amino acids / glycerol / lipids ;\n\n8(c)(i) 3.10−1.55 3.10−1.50 2\nor ;\n15 15\n0.10 / 0.11 ;\n\n8(c)(ii) any three from: 3\n1 temperature now not limiting\nor\ncarbon dioxide concentration now limiting ;\n2 closure of stomata ;\n3 lack of water / AW ;\n4 denaturation of enzymes\nor\nactive site no longer complementary to substrate / no ESCs form ;\n5 AVP ; e.g. ref. to optimum temperature / photorespiration occurs\n© UCLES 2023 Page 15 of 18\n\n8(c)(iii) similar shape but below high intensity curve ; 1\nQuestion Answer Marks", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p15.png", "../answer-assets/9700_w23_ms_42-p16.png" ] }, { "id": "9700-2023-on-42-q09", "question_id": "9700-2023-on-42-q09", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 (drink of water causes) increase in blood water potential / AW ;\n2 detected by, osmoreceptors / hypothalamus ;\n3 causes decrease in release of ADH (into blood in first hour) ;\n4 less water reabsorbed (from collecting ducts) ;\n5 (so) decrease in blood water potential / blood water potential returns to set point ;\n6 causes increase in release of ADH ;\n7 negative feedback ;\n© UCLES 2023 Page 16 of 18\n\n9(b) any four from: 4\nnervous system endocrine system\n1 communication action potential / impulse and hormone ;\n2 nature of electrical (and chemical) and chemical ;\ncommunication\n3 mode of neurone and blood ;\ntransmission\n4 response muscle and target, organs / tissue / cells ;\ndestination\n5 transmission fast(er) and slow(er) ;\nspeed\n6 location of specific / localised and (can be) widespread ;\neffect\n7 response speed fast(er) and slow(er) ;\n8 duration of short-lived / temporary and can be long-lasting / permanent ;\neffect\n© UCLES 2023 Page 17 of 18", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p16.png", "../answer-assets/9700_w23_ms_42-p17.png" ] }, { "id": "9700-2023-on-42-q10", "question_id": "9700-2023-on-42-q10", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 8, "status": "available", "reason": null, "text": "10(a) 1 dye / paint / clipping fur / collar / electronic chip ; 4\n2 death / birth / reproduction ;\n3 Lincoln ;\n4 repeated / replicated ;\n\n10(b) any four from: 4\n1 idea of negative impact on, the environment / ecosystems / habitat / food webs / food chain ;\n2 decreases biodiversity ;\n3 large / fast, increase in number ;\n4 competition for (named) resources ;\n5 ref. to new disease ;\n6 may be toxic\nor\nfew animals able to eat it ;\n7 attracts pollinators (away from native species) ;\n© UCLES 2023 Page 18 of 18", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_42-p18.png" ] }, { "id": "9700-2023-on-43-q01", "question_id": "9700-2023-on-43-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "1(a)(i) thylakoid(s) ; 1\n\n1(a)(ii) any four from: 4\nup to three descriptions (D) and one / two linked functions (F)\nD1 stacked / many (A / thylakoids) / large surface area ;\nF2 to increase light absorption ;\nD3 (thylakoid) membrane has, (named), pigments / photosystems / electron carriers / enzymes ;\nF4 (thylakoid membrane role is) light-dependent reaction / photophosphorylation / creates proton gradient / pump\nprotons / chemiosmosis / makes ATP ;\nD5 (thylakoid) lumen / space ;\nF6 accumulates H+ / high H+ concentration ;\nD7 appear green (under microscope) ;\nF8 as / so, chlorophyll absorbs red and blue light ;\n\n1(b)(i) Calvin (cycle) ; 1\n\n1(b)(ii) any two from: 2\n1 no start and end, point / molecules ;\n2 all, molecules / intermediates, present all the time ;\n3 ribulose bisphosphate / RuBP / 5C molecule, is regenerated ;\n4 numerical detail ;\n\n1(c)(i) B: oxygen ; 2\nD: sugar / hexose / glucose / triose phosphate / carbohydrate / starch ;\n\n1(c)(ii) 1 (oxygen linked to) aerobic respiration / oxidative phosphorylation ; 3\n2 (glucose stated as) source / store, of (chemical) energy / ATP / food ;\n3 ref. to energy flow through, food chains / food web / ecosystem ;\n© UCLES 2023 Page 7 of 16", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p07.png" ] }, { "id": "9700-2023-on-43-q02", "question_id": "9700-2023-on-43-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "2(a) 1 number of / range of (different), ecosystems / habitats ; 2\n2 number of species and their relative abundance ;\n\n2(b) any three from: 3\n1 to, store / contain, multiple / many, genome / DNA / nucleotide, sequences ;\n2 to, align / compare / search, sequences ;\n3 to, process / analyse / sort / calculate from, large quantities of data ;\n4 to, share / access, data / information from, others / elsewhere ;\n5 to save time / fast(er) ;\n\n2(c)(i) Anopheles ; 1\n\n2(c)(ii) three / 3 ; 1\n\n2(d)(i) any three from: 3\n1 less able / not able, to, adapt / evolve ;\n2 little variation for selection to act on ;\n3 few(er) (potentially), useful / beneficial, alleles ;\n4 all / most, (could be) killed by same, disease / selection pressure ;\n5 if due to small population size this decreases species survival chance ;\n\n2(d)(ii) low(er) genetic variation means high(er), conservation status / threat / vulnerability / endangerment / risk of extinction ; 1\n\n2(d)(iii) any three from: 3\ndoes not support because\n1 chimpanzee has, most / highest, genetic variation but is, EN / endangered ;\n2 minke whale has (joint), least / lowest, genetic variation but is, LC / least concern ;\n3 genetic variation, similar / same, but conservation status is different ;\n4 example ;\n5 gorilla is, most / critically, endangered but has high(er) genetic variation ;\n6 AVP ; e.g. ref. to data limited to only seven species\n© UCLES 2023 Page 8 of 16", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p08.png" ] }, { "id": "9700-2023-on-43-q03", "question_id": "9700-2023-on-43-q03", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 16, "status": "available", "reason": null, "text": "3(a) 1 (q2 = 440 or q2 = 0.4 ) 3\n1100\nq = √0.4\nor\nq = 0.632455532 ;\n2 (p = 1 – 0.632455532 or p = 0.367544468)\n2pq = 2 x 0.632455532  0.367544468\nor\n2pq = 0.4649110641 ;\n3 (heterozygotes = 2pq  1100 e.g. 511.4 or 511.5 or 511.6672 )\n511 / 512 ;\n\n3(b) any two from: 2\n1 colours / shades / categories / phenotypes, not distinct / not discrete / overlap / form a (gradual) range / include\nintermediates ;\n2 >1 / 4 / several / many, genes ;\n3 environment affects, it / colour / phenotype ;\n\n3(c)(i) any two from: 2\n1 (as climate changes) increase in CO concentration causes, stomatal aperture to decrease / stomata to be less open ;\n2\n2 less water, lost / evaporated / transpired (though stomata) ;\n3 compensates for / allows survival in, low water availability / dry conditions ;\n© UCLES 2023 Page 9 of 16\n\n3(c)(ii) any four from: 4\n1 (abscisic acid / ABA) binds to receptor on, (guard) cell surface membrane ;\n2 H+ stops moving, out of cell / into cell wall ;\n3 Ca2+ ions enter, cytoplasm / cell\nor\nCa2+ ions act as second messenger ;\n4 K+ ions leave cell ;\n5 water leaves cell, by osmosis / down water potential gradient ;\n6 less turgid / flaccid, guard cell(s) close stoma(ta) ;\n\n3(d)(i) any two from: 3\n1 0.1, (mol) increases / gives higher, rate (compared to control / normal) ;\n2 1(.0) and 10(.0), (mol) decrease / give lower, rate (compared to control / normal) ;\n3 10(.0) (mol) rate, stays (approx.) constant / plateaus / does not increase, over, time / (6) days ;\n4 data quote comparing rate at two concentrations on one day\nor\ndata quote comparing rate on two different days for 10 mol ;\n\n3(d)(ii) 1 protons / H+ (ions) ; 2\n2 cellulose ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p09.png", "../answer-assets/9700_w23_ms_43-p10.png" ] }, { "id": "9700-2023-on-43-q04", "question_id": "9700-2023-on-43-q04", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 7, "status": "available", "reason": null, "text": "4(a)(i) 1 DNA, joined / combined / made, from two / different, sources / species ; 2\n2 using (named), enzymes / vectors or to create a, GMO / transgenic organism ;\n\n4(a)(ii) to, test / compare, effect(iveness) of, genes / proteins / Bt and OCII / plants / varieties / A and B 1\nor\nto see which, (gene / plant / variety / of A and B), works, better / best ;\n\n4(a)(iii) to compare / provide a baseline / as a control ; 1\n© UCLES 2023 Page 10 of 16\n\n4(b) 1 A and B kill larvae ; 3\n2 GM increases, yield of / food from (potatoes) ;\n3 A, is best / kills most / works faster / should be grown / will provide most food ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p10.png", "../answer-assets/9700_w23_ms_43-p11.png" ] }, { "id": "9700-2023-on-43-q05", "question_id": "9700-2023-on-43-q05", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "5(a) highest: malic acid ; 2\nlowest: oleic acid ;\n\n5(b) any five from: 5\nsimilarities:\n1 use pyruvate ;\n2 occur in, cytoplasm / cytosol ;\n3 make / regenerate, NAD ;\n4 redox reaction ;\ndifferences:\n5 lactate / lactic acid, made in mammals and ethanol in yeast ;\n6 one step in mammals and two steps in yeast ;\n7 carbon dioxide made in yeast (not in mammals) ;\n8 reversible in mammals and irreversible in yeast ;\nQuestion Answer Marks", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p11.png" ] }, { "id": "9700-2023-on-43-q06", "question_id": "9700-2023-on-43-q06", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) any two from: 2\n1 transparent phenotype (reappears) in F2 (but not F1) ;\n2 so it is, inherited / passed down / genetic / not environmental ;\n3 new / recessive, allele ;\n\n6(a)(ii) 9 : 3 : 3 : 1 ; 1\n© UCLES 2023 Page 11 of 16\n\n6(a)(iii) any four from: 4\n1 two genes ;\n2 on separate chromosomes / not linked ;\n3 not sex-linked / autosomal ;\n4 each gene has / both genes have, two alleles ;\n5 albino / white stripes, is recessive (allele) ;\n6 transparent / non-gold, is recessive (allele) ;\n7 wild type is dominant for both genes ;\n\n6(b) any four from: 4\n1 homologous chromosomes, pair up / form bivalents ;\n2 at prophase I ;\n3 independent assortment / random orientation\nor\nindependent segregation ;\n4 (happens) at metaphase I\nor\nat anaphase I ;\n5 one chromosome of (each) pair has dominant allele and one has recessive ;\n6 four, combinations / permutations / different gametes ;\n7 worked example / diagram ;\n© UCLES 2023 Page 12 of 16", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p11.png", "../answer-assets/9700_w23_ms_43-p12.png" ] }, { "id": "9700-2023-on-43-q07", "question_id": "9700-2023-on-43-q07", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "7(a)(i) any four from: 4\nboth\n1 acetylcholine, in / from, vesicles ;\n2 many mitochondria ;\n3 have presynaptic and postsynaptic membranes ;\n4 (synaptic) cleft / gap ;\n5 have receptor(s) (for ACh / neurotransmitter) ;\n6 presynaptic, Ca2+, entry / channels\nor\npostsynaptic Na+, entry / channels ;\n\n7(a)(ii) any three from: 3\n1 few(er) Ca2+ ions, leave sarcoplasmic reticulum / enter sarcoplasm ;\n2 few(er) Ca2+ ions bind to troponin ;\n3 few(er) troponin molecules change shape ;\n4 few(er) tropomyosin molecules move ;\n5 few(er) myosin-binding sites, uncovered / exposed ;\n6 few(er), actin-myosin cross bridges form / myosin (heads) bind to actin ;\n7 AVP ; e.g. lack of P leads to less ATP formed\ni\n8 AVP ; e.g. myosin-actin cross-bridges do not break / myosin heads do not reset\n\n7(b) A: adenylyl cyclase ; 2\nB: protein kinase A ;\nQuestion Answer Marks", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p13.png" ] }, { "id": "9700-2023-on-43-q08", "question_id": "9700-2023-on-43-q08", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 6, "status": "available", "reason": null, "text": "8(a) letter X on rising slope to the left of the angle where line plateaus ; 1\n\n8(b)(i) reverse transcriptase ; 1\n\n8(b)(ii) transcription factor(s) ; 1\n© UCLES 2023 Page 13 of 16\n\n8(b)(iii) any three from: 3\n1 in high light intensity plant can photosynthesise more ;\n2 so they need (more) / upregulate / increase / make (more) (named) enzymes / proteins, for photosynthesis ;\n3 (plus) named, enzyme / protein (for photosynthesis) ;\n4 (named) pigments to protect cells from excess light ;\n5 enzymes to make, sucrose / starch / amino acids ;\n6 proteins for, sucrose / amino acid, transport ;\n7/8 AVP ;; e.g. DELLA breaks down releasing, phytochrome interacting factors / PIF\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p13.png", "../answer-assets/9700_w23_ms_43-p14.png" ] }, { "id": "9700-2023-on-43-q09", "question_id": "9700-2023-on-43-q09", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "9(a)(i) any three from: 3\n1 (random) mutation(s) allows detection of high frequency ;\n2 selection pressure is bat (predation) ;\n3 those that can detect, high frequencies / bats, survive / don’t get eaten / have selective advantage / are selected for ;\n4 these, reproduce / pass on (beneficial) allele(s) ;\n5 those that can detect high sounds / beneficial alleles, increase (in frequency / in population) ;\n\n9(a)(ii) any four from: 4\n1 ref. to receptor / generator, potential ;\n2 vesicles of (named) neurotransmitter, move towards / fuse with, (presynaptic) membrane ;\n3 (named) neurotransmitter, release / exocytosis ;\n4 neurotransmitter binds to receptors on sensory neurone ;\n5 Na+ / sodium, ions enter (sensory neurone) ;\n6 depolarisation (of membrane of sensory neurone) ;\n7 ref. to threshold potential / all-or-nothing response ;\n© UCLES 2023 Page 14 of 16\n\n9(b) any three from: 3\nS1 sympatric (speciation) ;\nS2 different mutations ;\nS3 gave, (named) phenotypic / behavioural, differences ;\nS4 which gave behavioural, isolation / separation ;\nS5 (leading to) inability to reproduce together / reproductive isolation / genetic isolation / no gene flow between them ;\nor\nany three from:\nA1 allopatric (speciation) ;\nA2 geographical, separation / barrier, in the past ;\nA3 different, mutations / selection pressures ;\nA4 gave, (named) phenotypic / behavioural, differences ;\nA5 inability to reproduce together / reproductive isolation / genetic isolation / no gene flow between them, after populations\nre-join ;\n© UCLES 2023 Page 15 of 16", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p14.png", "../answer-assets/9700_w23_ms_43-p15.png" ] }, { "id": "9700-2023-on-43-q10", "question_id": "9700-2023-on-43-q10", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 7, "status": "available", "reason": null, "text": "10 any seven from: 7\n1 genetic engineering / recombinant (DNA technology) ;\n2 (named) drug / treatment / protein, from, (GM) bacteria / (GM) yeast / (named) (GM)O ;\n3 make insulin (drug for diabetes) ;\n4 make factor VIII (drug for haemophilia) ;\n5 make adenosine deaminase (drug for SCID) ;\n6 genetic, screening / diagnosis / testing ;\n7 (detect) BRCA1 / BRCA2 ;\n8 (detect number of repeats / allele for) Huntington’s ;\n9 (detect allele for) cystic fibrosis / CFTR ;\n10 example of action if diagnosis positive ;\n11 gene therapy ;\n12 insert / add, normal allele into (named), cells / tissue (of person) ;\n13 to treat, eye disease(s) / LCA / Leber’s congenital amaurosis ;\n14 to treat SCID ;\n15/16 AVP ; ; e.g. ref. to help / develop, xenotransplantation\nGM / antigen-free, pigs / animals, to source, tissues / organs, for transplants\nGM plants to make vaccines\nGM / recombinant / DNA / mRNA, vaccines\nrecombinant antibody technology\nother / different, recombinant therapeutic protein / genetic screening / gene therapy, example\n© UCLES 2023 Page 16 of 16", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_43-p16.png" ] }, { "id": "9700-2023-on-51-q01", "question_id": "9700-2023-on-51-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a)(i) any one from: 1\n1 idea that size (of apple) may not be, related / proportional, to ripeness ;\n2 idea that (individual) apples may, ripen at different rates / AW ;\n3 idea that other factors may affect, ripeness of apples / diameter of apples ;\n\n1(a)(ii) any one from: 1\n1 (pick apples with the) same / similar / AW, sugar content / colour / softness / age ;\n2 test / measure / AW, sugar content / colour / softness / age (of apples) ;\n\n1(b) 1 correct axis labels ; 2\n2 correct shaped line ;\n\n1(c)(i) 1 90 ; 2\n2 50 ;\n© UCLES 2023 Page 7 of 10\n\n1(c)(ii) any nine from: 9\n1 idea of test on at least 5 days ;\n2 use apples from same, tree / variety / type ;\n3 use, same / stated, storage conditions (of apples) ;\nprepare apple extract solutions:\n4 remove the, skin / seeds, of the apple ;\n5 use, set / stated, mass of apple ;\n6 method to, grind / AW, apple ;\n7 centrifuge / filter ;\nmeasure ascorbic acid concentration using DCPIP:\n8 place, set / stated, volume of (apple extract) solution in, conical flask / AW ;\n9 idea of adding DCPIP dropwise to (apple extract) solution until blue colour remains ;\n10 shake / mix / AW (after each drop of DCPIP) ;\n11 measure / record, volume of DCPIP used (to reach end point) ;\n12 read volume from bottom of meniscus (in burette) ;\n13 use at least three replicates for each day and calculate a mean (DCPIP volume) ;\n14 safety comment with hazard and risk and precaution ;\nhazard risk precaution\nDCPIP irritant / toxin / allergy gloves / goggles / mask /\nPPE\napples allergy gloves / goggles / mask /\nPPE / medication / do not\neat\nknife / scalpel injury cut away from hand\n\n1(d) any two from: 2\n1 data is continuous ;\n2 scatter diagram, suggests a linear, relationship ;\n3 data is normally distributed ;\n© UCLES 2023 Page 8 of 10\n\n1(e) any three from: 3\nfor the conclusion:\n1 apples have the second lowest –carotene concentration (of the fruits shown) ;\n2 quoted data from Fig. 1.3 to support ;\n3 idea that spread of data for apple is lower (than most fruits that were tested, as SD is smaller)\nagainst the conclusion:\n4 idea that need to calculate, SE / 95% CI (to make a conclusion) ;\n5 no statistical test carried out ;\n6 idea that only 5 fruits were tested ;\nQuestion Answer Marks", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_51-p07.png", "../answer-assets/9700_w23_ms_51-p08.png", "../answer-assets/9700_w23_ms_51-p09.png" ] }, { "id": "9700-2023-on-51-q02", "question_id": "9700-2023-on-51-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) independent variable: type / AW , of trypsin ; 2\ndependent variable: time (taken to break down gelatine) ;\n\n2(a)(ii) any one from: 1\n1 pH (of solution) ;\n2 surface area / mass / volume, of cube ;\n3 concentration of, gelatine / collagen, in cube ;\n\n2(b)(i) mean = 131.1 ; 1\n\n2(b)(ii) s = 3.2 ; 1\n\n2(b)(iii) any three from: 3\n1 critical value (at degrees of freedom = 22 and p = 0.05) = 2.074 ;\n2 calculated (t–) value / 2.663 is, greater than, critical (t–) value / 2.074 ; ora\n3 null hypothesis is rejected ;\n4 there is a significant difference (at p = 0.05) ;\n© UCLES 2023 Page 9 of 10\n\n2(b)(iv) any two from: 2\n1 idea that salmon trypsin is adapted to colder temperatures ; ora\n2 (at 20 °C) salmon trypsin forms enzyme–substrate complexes at a faster rate (than pig trypsin) ; ora\n3 AVP ;\n© UCLES 2023 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_51-p09.png", "../answer-assets/9700_w23_ms_51-p10.png" ] }, { "id": "9700-2023-on-52-q01", "question_id": "9700-2023-on-52-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 16, "status": "available", "reason": null, "text": "1(a) any two from 2\n1 low tide ;\n2 day / date / month / season ;\n3 (same) rocky shore / (same) location ;\n4 (mid-shore) zone ;\n5 random selection of rock pools ;\n6 deepest part of rock pool measured ;\n\n1(b)(i) there is no correlation between, species diversity / number of (different) species and depth ; 1\n\n1(b)(ii) any three from 3\n1 critical value for (p = 0.05) = 0.350 ;\n2 value for, r / calculated value, is > than critical value ;\ns\n3 null hypothesis is rejected ;\n4 there is a significant correlation (between depth of rock pool and species diversity) ;\n5 there is a positive correlation (between rock pool depth and species diversity) ;\n\n1(b)(iii) 1. scatter diagram, does not indicate, a linear, relationship ; 1\n2. (data is) not normally distributed ;\n3. species diversity / number of species, is not continuous ;\n\n1(c) any two from 2\n1 location of the rocky shore is unknown ;\n2 position of the mid-shore zone is unknown ;\n3 size of rock pools is unknown ;\n4 location of rock pool is unknown ;\n5 height, of tide / tides, unknown ;\n© UCLES 2023 Page 9 of 12\n\n1(d) any seven from 7\nsampling process\n1 belt transect ;\n2 place a, rope / AW, from LWM to HWM ;\n3 sample at regular intervals along the transect ;\n4 use a quadrat ;\n5 same / same size of, quadrat ;\nmeasuring process\n6 method of identifying species (of algae) ;\n7 take care not to miss small species ;\n8 (count / record) number of (different) species (of algae) (in each quadrat) ;\n9 method for determining abundance of each species (in each quadrat) ;\n10 repeat belt transect at two other positions along the shore and calculate means ;\n11 named suitable hazard and risk and precaution ;\n12 AVP ;\n© UCLES 2023 Page 10 of 12", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_52-p09.png", "../answer-assets/9700_w23_ms_52-p10.png" ] }, { "id": "9700-2023-on-52-q02", "question_id": "9700-2023-on-52-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 14, "status": "available", "reason": null, "text": "2(a) any one from: 1\nsuitable method for measuring a curve ;\nstraighten shoot (before measuring) ;\n\n2(b)(i) 38.7 and 45.3 ; 1\n\n2(b)(ii) difference is significant ; 1\n\n2(c) any two from: 3\n1 ABA reduces (shoot) growth ;\n2 SA increases (shoot) growth (by day 5) ;\n3 ABA prevents, cell elongation / cell division\nor\nSA stimulates, cell elongation / cell division ;\n4 description of the effect on growth by treatment C (ABA + SA) ;\n5 ABA (partly) counteracts the effect (on growth) of SA\nor\nSA (partly) counteracts the effect (on growth) of ABA ;\n\n2(d) 1 appropriate method of applying the solutions / hormones, to the roots only ; 3\nmax. two from:\n2 same volume of solutions ;\n3 measuring shoot lengths on day 1 and day 5 ;\n4 named example of condition which is same as shoot spraying experiment ;\n5 method to identify presence of hormone in shoot ;\n© UCLES 2023 Page 11 of 12\n\n2(e)(i) one mark per row 3\ngene effect on gene expression\nABA alone SA alone\nCDKB2 large decrease no change / small increase ;\nKRP4 large increase no change / small increase ;\nCycD6 large decrease no change / small decrease ;\n\n2(e)(ii) conclusion 1 2\nfully supports and mRNA (ABA + SA / batch C) lower than with ABA (batch B) / ora ;\nconclusion 2\npartially supports and mRNA (ABA + SA / batch C) higher than with ABA (batch B) but not as high as with water (batch\nA) / SA (batch D)\nor\nno statistical test carried out ;\n© UCLES 2023 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_52-p11.png", "../answer-assets/9700_w23_ms_52-p12.png" ] }, { "id": "9700-2023-on-53-q01", "question_id": "9700-2023-on-53-q01", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a)(i) any one from: 1\n1 idea that size (of apple) may not be, related / proportional, to ripeness ;\n2 idea that (individual) apples may, ripen at different rates / AW ;\n3 idea that other factors may affect, ripeness of apples / diameter of apples ;\n\n1(a)(ii) any one from: 1\n1 (pick apples with the) same / similar / AW, sugar content / colour / softness / age ;\n2 test / measure / AW, sugar content / colour / softness / age (of apples) ;\n\n1(b) 1 correct axis labels ; 2\n2 correct shaped line ;\n\n1(c)(i) 1 90 ; 2\n2 50 ;\n© UCLES 2023 Page 7 of 10\n\n1(c)(ii) any nine from: 9\n1 idea of test on at least 5 days ;\n2 use apples from same, tree / variety / type ;\n3 use, same / stated, storage conditions (of apples) ;\nprepare apple extract solutions:\n4 remove the, skin / seeds, of the apple ;\n5 use, set / stated, mass of apple ;\n6 method to, grind / AW, apple ;\n7 centrifuge / filter ;\nmeasure ascorbic acid concentration using DCPIP:\n8 place, set / stated, volume of (apple extract) solution in, conical flask / AW ;\n9 idea of adding DCPIP dropwise to (apple extract) solution until blue colour remains ;\n10 shake / mix / AW (after each drop of DCPIP) ;\n11 measure / record, volume of DCPIP used (to reach end point) ;\n12 read volume from bottom of meniscus (in burette) ;\n13 use at least three replicates for each day and calculate a mean (DCPIP volume) ;\n14 safety comment with hazard and risk and precaution ;\nhazard risk precaution\nDCPIP irritant / toxin / allergy gloves / goggles / mask /\nPPE\napples allergy gloves / goggles / mask /\nPPE / medication / do not\neat\nknife / scalpel injury cut away from hand\n\n1(d) any two from: 2\n1 data is continuous ;\n2 scatter diagram, suggests a linear, relationship ;\n3 data is normally distributed ;\n© UCLES 2023 Page 8 of 10\n\n1(e) any three from: 3\nfor the conclusion:\n1 apples have the second lowest –carotene concentration (of the fruits shown) ;\n2 quoted data from Fig. 1.3 to support ;\n3 idea that spread of data for apple is lower (than most fruits that were tested, as SD is smaller)\nagainst the conclusion:\n4 idea that need to calculate, SE / 95% CI (to make a conclusion) ;\n5 no statistical test carried out ;\n6 idea that only 5 fruits were tested ;\nQuestion Answer Marks", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_53-p07.png", "../answer-assets/9700_w23_ms_53-p08.png", "../answer-assets/9700_w23_ms_53-p09.png" ] }, { "id": "9700-2023-on-53-q02", "question_id": "9700-2023-on-53-q02", "subject": "9700", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) independent variable: type / AW , of trypsin ; 2\ndependent variable: time (taken to break down gelatine) ;\n\n2(a)(ii) any one from: 1\n1 pH (of solution) ;\n2 surface area / mass / volume, of cube ;\n3 concentration of, gelatine / collagen, in cube ;\n\n2(b)(i) mean = 131.1 ; 1\n\n2(b)(ii) s = 3.2 ; 1\n\n2(b)(iii) any three from: 3\n1 critical value (at degrees of freedom = 22 and p = 0.05) = 2.074 ;\n2 calculated (t–) value / 2.663 is, greater than, critical (t–) value / 2.074 ; ora\n3 null hypothesis is rejected ;\n4 there is a significant difference (at p = 0.05) ;\n© UCLES 2023 Page 9 of 10\n\n2(b)(iv) any two from: 2\n1 idea that salmon trypsin is adapted to colder temperatures ; ora\n2 (at 20 °C) salmon trypsin forms enzyme–substrate complexes at a faster rate (than pig trypsin) ; ora\n3 AVP ;\n© UCLES 2023 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2023-Oct-Nov/ms/9700_w23_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2023-oct-nov/9700_w23_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w23_ms_53-p09.png", "../answer-assets/9700_w23_ms_53-p10.png" ] }, { "id": "9700-2024-m-42-q01", "question_id": "9700-2024-m-42-q01", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "1(a) A – label line to collecting duct ; 4\nB – label line to inner part of Bowman’s capsule ;\nC – label line to, loop of Henle /\npart of collecting duct below level of convoluted tubules ;\nD – label line to wider blood vessel entering Bowman’s capsule ;\n\n1(b) any four from: 4\n1 microvilli, for large surface area / increases surface area (for reabsorption) ;\n2 cotransporter (proteins) for movement of, glucose / amino acids\n(with sodium ions) ;\n3 tight junctions / described, to, stop substances passing in between cells /\ncause substances to pass though cells ;\n4 many mitochondria to provide ATP for, active transport / pumping of Na+ ;\n5 folded basal membrane for many sodium (potassium) pumps ;\n© Cambridge University Press & Assessment 2024 Page 5 of 21", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p05.png" ] }, { "id": "9700-2024-m-42-q02", "question_id": "9700-2024-m-42-q02", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 7, "status": "available", "reason": null, "text": "2(a) any four from: 4\n1 test cross ;\n2 cross (tall plant) with dwarf plant ;\n3 (dwarf plant must be) le le / homozygous recessive ;\n4 if all offspring are tall then parent plant is, Le Le / homozygous dominant ;\n5 if offspring are 1:1 tall:dwarf / if any offspring are dwarf,\nthen parent plant is, Le le / heterozygous ;\n6 AVP ; e.g. detail of breeding experiment\ncross pollination, seed harvesting, seed germination\n\n2(b)(i) hormone / cell signalling (molecule) ; A ligand / plant growth regulator 1\n\n2(b)(ii) 1 (causes) cell elongation ; A increases cell, division / mitosis 2\n2 idea that plant / stem, grows taller ;\nQuestion Answer Marks", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p06.png" ] }, { "id": "9700-2024-m-42-q03", "question_id": "9700-2024-m-42-q03", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 14, "status": "available", "reason": null, "text": "3(a) 1 both alleles of a, gene / genotype, are the same ; 2\n2 phenotype / effect, of (recessive) allele is masked by a dominant allele\nor\ntwo copies of the (recessive) allele are needed for phenotype to be displayed\nor\nalleles only affect the phenotype in the absence of a dominant allele\nor\n(genotype) must be homozygous for the (recessive) allele to affect the phenotype ;\n© Cambridge University Press & Assessment 2024 Page 6 of 21\n\n3(b)(i) number of heterozygous people = 1 680 000 ; ; ; 3\nmust be to 3 significant figures or more\nA 1 675 000 to 1 685 000 ; ; ;\nR 1 700 000\nmax 2 if decimal places in final answer\nallow max 2 for working if final answer incorrect\n(q = √10 800 / 67 100 000 or √0.000161 or 0.0127)\np = 1 – 0.0127 or 0.987\n(2pq = 2  0.9873  0.0127 or 0.0251)\ncalculation for number of heterozygous people = 67 100 000  0.0251 or 2pq\n\n3(b)(ii) any three from: 3\n1 ref. natural selection ;\n2 selection pressure against cystic fibrosis (CF) ;\n3 (people with) CF do not survive as long / AW ;\n4 heterozygotes are calculated from a smaller CF population / AW ;\n5 (some) people with CF who have died will have passed on CF allele ;\n© Cambridge University Press & Assessment 2024 Page 7 of 21\n\n3(c)(i) any three from: 3\n1 (median) predicted life expectancy increased (over time) ;\n2 data quote ; e.g. from 2008 to 2020 increase from 38.8 to 50.6 years\nincrease of 11.8\n% increase of 30.4\n3 treatment can be started early ;\n4 better treatment / improved care (between 2008 and 2020) ;\n\n3(c)(ii) any three from: 3\n1 reduces worry / AW, if result is negative ; ora\n2 can make informed reproductive decisions / AW ;\n3 cost / availability, of test ;\n4 plan for care of child with CF ;\n5 idea of further genetic testing ; e.g. counselling / testing of embryo / testing of partners\n6 idea that test is not 100% accurate ;\n7 problems related to, stigma / discrimination / insurance / confidentiality ;\n© Cambridge University Press & Assessment 2024 Page 8 of 21", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p06.png", "../answer-assets/9700_m24_ms_42-p07.png", "../answer-assets/9700_m24_ms_42-p08.png" ] }, { "id": "9700-2024-m-42-q04", "question_id": "9700-2024-m-42-q04", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 14, "status": "available", "reason": null, "text": "4(a) 1 temperature increases and milk yield decreases ; 2\n2 comparative data quote – April = 10 °C and 792–798 kg cow–1,\nAugust = 18 °C and 711–716 kg cow–1 ;\n\n4(b) 1 continuous 3\nand\n(milk yield) does not fall into distinct classes / shows a range /\nintermediates / no distinct categories / AW ;\n2 environment\nand\n(milk yield) affected by air temperature ;\n3 genetic / polygenic\nand\nmany / 20, genes have effect (on milk yield)\nor\nheat-tolerant cattle have lower milk yield than Holstein Friesian cattle ;\n© Cambridge University Press & Assessment 2024 Page 9 of 21\n\n4(c) any three from: 3\n1 SLICK allele increases milk yield (in both months / at both temperatures) ;\n2 in March / at 5 °C, there is a small difference (between milk yield) ;\n3 in September / at 14 °C, there is a larger difference (between milk yields) ;\n4 cattle with SLICK allele maintain milk yield\n(in both months / at both temperatures) ;\n5 comparative data quote to support mp1–mp4 ;\nMonth Holstein without Holstein with\nSLICK / kg cow–1 SLICK / kg cow–1\nMarch / at 5 °C 780–785 795–800\nSept / at 14 °C 690–700 770–780\n© Cambridge University Press & Assessment 2024 Page 10 of 21\n\n4(d) any six from: 6\ngene editing selective breeding\n1 (first) offspring have SLICK allele ;\n2 can have, negative / unknown, effects ;\n3 presence of SLICK allele (in offspring) can be confirmed by, ;\ngenetic testing / phenotypic observation\n4 done by humans / artificial methods ;\n5 only, and affects many genes ;\nPRLR / one, gene is affected\n6 all offspring have SLICK allele and some offspring have SLICK allele ;\n7 immediate / one generation and performed over (many) generations ;\n8 performed on, and mating ;\nembryos / zygotes / cells / artificial insemination\n9 technical requirements and mating / performed on the farm ;\ne.g. laboratory, training, molecular e.g. physiological method\nmethod\n10 maintains, heterozygosity / genetic and loss of, heterozygosity / genetic ;\nvariation / variation /\ndesirable characteristics desirable characteristics\n11 regulatory approval and no regulatory approval ;\n12 no outbreeding required and outbreeding required ;\n© Cambridge University Press & Assessment 2024 Page 11 of 21", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p09.png", "../answer-assets/9700_m24_ms_42-p10.png", "../answer-assets/9700_m24_ms_42-p11.png" ] }, { "id": "9700-2024-m-42-q05", "question_id": "9700-2024-m-42-q05", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 6, "status": "available", "reason": null, "text": "5 (many) generations / (many) years / (a long) time / AW ; 6\nmutations / similarities ;\nmeiosis / crossing over / recombination ;\ndatabases ;\namino acid ;\nmicroarray ;\nQuestion Answer Marks", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p12.png" ] }, { "id": "9700-2024-m-42-q06", "question_id": "9700-2024-m-42-q06", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "6(a) absorb carbon dioxide (produced by peas) ; 1\n\n6(b) any two from: 2\n1 idea of repeatability ;\n2 check to see how consistent the results are /\nthe more consistent the results, the more valid the results /\ncarry out a (named) statistical test or measure /\ncalculate standard deviation / calculate standard error ;\n3 a control respirometer / described ; e.g. with glass beads instead of peas\n4 ref. to checking variables (other than temperature) ;\ne.g. volume of germinating peas / volume / concentration of KOH\n\n6(c) acclimatisation / equilibration / AW ; 1\n© Cambridge University Press & Assessment 2024 Page 12 of 21\n\n6(d) 5 points plotted accurately ; 2\nsmooth curve drawn linking all plotted points / curve of best fit ;\nR extrapolation\n\n6(e) any three from: 3\n1 ref to enzymes ;\n2 (as temperature increases) kinetic energy increases ;\n3 (so) rate increases, due to more enzyme-substrate complexes formed\n(in same time)\nor\n(so) rate increases, due to higher, proportion / frequency, of,\nsuccessful / effective, collisions ;\n4 (rate decreases after 30 °C) due to denaturation of enzymes ;\n5 further detail ; e.g. active site shape change / ref. optimum temperature\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p12.png", "../answer-assets/9700_m24_ms_42-p13.png" ] }, { "id": "9700-2024-m-42-q07", "question_id": "9700-2024-m-42-q07", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "7(a)(i) light not absorbed / stop photosynthesis / stop photoactivation / 1\nstop light dependent stage ;\n© Cambridge University Press & Assessment 2024 Page 13 of 21\n\n7(a)(ii) any three from: 3\n1 all decrease in absorbance (with time) ;\n2 (all decrease) at constant rate ;\n3 green, highest absorbance (throughout) /\nabsorbance stays fairly constant / smallest decrease in absorbance ;\nora red\n4 smallest rate of decrease in green ; ora red\n5 data quote – 2 colours compared to support mp1 or mp3 ;\n4 mins\ngreen 1.44\nblue 0.90\nred 0.70\n\n7(a)(iii) any three from: 3\nwith red light ora green light\n1 more, light / energy, absorbed (by chlorophyll) ;\n2 (so) more, photoactivation / electrons emitted ;\n3 more / faster rate of, electrons transferred to DCPIP ;\n4 more / faster, decolourisation of DCPIP ;\n© Cambridge University Press & Assessment 2024 Page 14 of 21\n\n7(b) 3\nfactor stage ✓or \nCalvin cycle ✓\ncarbon dioxide\n;\nconcentration\nphotophosphorylation \nCalvin cycle \nlight intensity ;\nphotophosphorylation ✓\nCalvin cycle ✓\ntemperature ;\nphotophosphorylation ✓\nQuestion Answer Marks", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p13.png", "../answer-assets/9700_m24_ms_42-p14.png", "../answer-assets/9700_m24_ms_42-p15.png" ] }, { "id": "9700-2024-m-42-q08", "question_id": "9700-2024-m-42-q08", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 11, "status": "available", "reason": null, "text": "8(a)(i) chemoreceptor ; 1\n\n8(a)(ii) any two from: 2\n1 (different mycobacterial species produce) the same / similar,\nchemicals / proteins ;\n2 (since) share common ancestors / same genus / share many genes /\nclosely related ;\n3 same chemoreceptors stimulated ;\n© Cambridge University Press & Assessment 2024 Page 15 of 21\n\n8(b) 2\nkingdom Animalia\nphylum Chordata\nclass Mammalia\norder Rodentia\nfamily Nesomyidae\ngenus Cricetomys\nspecies gambianus\n4 correct = 2 marks\n1 / 2 / 3 correct = 1 mark\n© Cambridge University Press & Assessment 2024 Page 16 of 21\n\n8(c) any four from: 4\ncomparative statements required\nEukarya Bacteria\n1 linear DNA and plasmids / circular DNA ;\n2 histones and no histones ;\n3 cell walls only in some and cell walls in all ;\n4 cellulose / chitin, cell walls and peptidoglycan cell wall ;\n5 divide by mitosis and divide by binary fission ;\n6 some sexual reproduction and asexual reproduction ;\n7 (70S and) 80S ribosomes and 70S ribosomes (only) ;\n8 have cells > 5 m diameter and cells1–5 m diameter ;\n\n8(d) any two from: 2\n1 have DNA or RNA ;\n2 nucleic acid is double or single stranded ;\n3 AVP ; e.g.presence or absence of phospholipid envelope\npresence or absence of tail sheath\ntype of host\ntype of disease caused\n© Cambridge University Press & Assessment 2024 Page 17 of 21", "source_pages": [ 15, 16, 17 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p15.png", "../answer-assets/9700_m24_ms_42-p16.png", "../answer-assets/9700_m24_ms_42-p17.png" ] }, { "id": "9700-2024-m-42-q09", "question_id": "9700-2024-m-42-q09", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 11, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 (blue) light decreases germination / AW ;\n2 as intensity of (blue) light increases percentage germination decreases ;\n3 data quote ;\nlight intensity percentage\n/ arbitrary units (au) germination\n0 (dark) 98.0\n36 76.9\n48 45.0\n57 14.7\n4 (blue) light increases (the concentration of) ABA ;\n5 ABA inhibits gibberellin (synthesis / activity) ;\n6 any further valid suggestion of ABA action ;\ne.g. DELLA not broken down / promotes dormancy / stops gene expression\n© Cambridge University Press & Assessment 2024 Page 18 of 21\n\n9(b) any seven from: 7\n1 auxin binds to receptor on the cell surface membrane ;\n2 stimulates proton pumps ;\n3 protons move from, cytoplasm / cell, to cell wall ;\n4 pH of cell wall decreases ;\n5 expansins activated ;\n6 loosens linkage between cellulose microfibrils ;\n7 by breaking hydrogen bonds ; Ignore weakening bonds\n8 K+ channels open ;\n9 K+ diffuse into, cytoplasm / cell ;\n10 water potential (of cytoplasm / cell) decreases ;\n11 water enters by osmosis ;\n12 increase in turgor pressure / volume of cell increases ;\n© Cambridge University Press & Assessment 2024 Page 19 of 21", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p18.png", "../answer-assets/9700_m24_ms_42-p19.png" ] }, { "id": "9700-2024-m-42-q10", "question_id": "9700-2024-m-42-q10", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 troponin binds Ca2+ and changes shape ;\n2 (so) tropomyosin moves away from the binding sites on actin ;\n3 myosin heads, bind to / form cross-bridges, with actin ;\n4 myosin head, pulls actin / performs power stroke, to,\neither\nshorten / contract, sarcomere\nor\ncause Z lines to move closer together / Z lines move closer to M lines ;\n5 myosin head, is ATPase / binds to ATP, to allow detachment ;\n\n10(b) any three from: 3\n1 succinylcholine binds to ACh receptors\nor\nsuccinylcholine acts as a competitive inhibitor ;\nR if binds to active site of receptor\n2 (sodium ions) channel proteins do not open ; R if voltage gated\n3 sodium ions do not enter, muscle cell / sarcoplasm ;\n4 sarcolemma / post-synaptic membrane, not depolarised ;\n© Cambridge University Press & Assessment 2024 Page 20 of 21\n\n10(c) any three from: 3\n1 sex-linked / gene on X chromosome ;\n2 recessive (allele) ;\n3 males only have one, copy of gene / allele / X chromosome ;\n4 female heterozygotes, do not have DMD / are carriers\nor\nonly homozygous females have DMD ;\n© Cambridge University Press & Assessment 2024 Page 21 of 21", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_42-p20.png", "../answer-assets/9700_m24_ms_42-p21.png" ] }, { "id": "9700-2024-m-52-q01", "question_id": "9700-2024-m-52-q01", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 17, "status": "available", "reason": null, "text": "1(a)(i) concentration of, sodium chloride (solution) ; 1\n\n1(a)(ii) distilled water / deionised water / pure water (as diluent) ; 2\ncorrect volumes of stock solution and water (in Table 1.1) ;\n\n1(b)(i) any one from: 1\n1 allows valid comparison (between onions in different sodium chloride concentrations) ;\n2 allows comparison as, initial / starting, mass (of onions) is, not constant / AW ;\n\n1(b)(ii) any four from: 4\n1 idea that the conclusion is only supported for onions left for hours ; ora\n2 (ref. to intercept of x-axis / 0% change in mass / water potential of onions when left for) 48 hours is 3.1% sodium\nchloride ;\n3 ref. to qualified experimental error ;\n4 ref. to anomalous result(s) on graph ;\n5 idea that line of best fit may give different value ;\n6 ref. to intermediate concentrations (of sodium chloride) not tested (between 1% and 5% sodium chloride) ;\n7 ref. to no, statistical analysis / standard error / 95% CI ;\n8 idea that not all onion cells have the same water potential ;\n© Cambridge University Press & Assessment 2024 Page 5 of 9\n\n1(c)(i) any six from: 6\n1 use a minimum of five stated temperatures ;\n2 suitable method to, maintain a constant temperature (for each replicate / experiment) ;\n3 same / stated, variety / age / AW, of turnips ;\n4 same / stated, dimensions / AW, of turnip block ;\n5 ref. to apparatus for obtaining same size of turnip blocks ;\n6 for each temperature, place turnip blocks in, a beaker / AW, of (fresh / new) distilled water ;\n7 at each temperature, measure the initial mass and the final mass after a, set / stated, time ;\n8 for each temperature, use at least three different blocks and calculate a mean ;\n9 method to remove excess water from turnip block (before measuring final mass) ;\n\n1(c)(ii) 1 horizontal axis label: 2\ntemperature, C\nand\nvertical axis label:\nrate of osmosis ;\n2 appropriately shaped line ;\n© Cambridge University Press & Assessment 2024 Page 6 of 9\n\n1(c)(iii) ref. to hazard and risk and precaution ; 1\nhazard Risk Precaution\nknife / blade / AW injury cut away from the hand / cut\ndown on to a, board / tile / AW\nturnip allergy irritant wear gloves / PPE\nhot water / water-bath / method scald / burn / injury wear, (heat resistant)\nof heating gloves / PPE\nuse, tongs / AW\nQuestion Answer Marks", "source_pages": [ 5, 6, 7 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_52-p05.png", "../answer-assets/9700_m24_ms_52-p06.png", "../answer-assets/9700_m24_ms_52-p07.png" ] }, { "id": "9700-2024-m-52-q02", "question_id": "9700-2024-m-52-q02", "subject": "9700", "year": 2024, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "2(a) to prevent the parent (fruit flies), reproducing / mating / AW, with the, first generation / offspring / AW ; 1\n\n2(b) to separate male and female fruit flies: 1\nuse hand lens / (binocular) microscope / AW\nor\nref. to difference between male and female (fruit flies)\nand\nto place fruit flies:\nuse a, paint brush / pooter / forceps / AW ;\n\n2(c)(i) there is no difference between, the observed and expected, results ; 1\n© Cambridge University Press & Assessment 2024 Page 7 of 9\n\n2(c)(ii) 1 correct values of E ; 3\n2 correct values of (O–E)2 / E ;\noffspring O E (O–E)2 / E\nphenotype\ndark red eyes 691 702 0.172\n121 / 702\nbrown eyes 260 234 2.889\n676 / 234 = 26 / 9\nbright red 225 234 0.346\neyes 121 / 234\nwhite eyes 72 78 0.462\n36 / 78 = 6 / 13\ntotal 1248 (1248) 3.869\n3 (2 =) 3.869 ;\n\n2(c)(iii) 1 ref. to correct critical value = 7.815 (p = 0.05 and df = 3) ; 2\n2 calculated value of,  2 / 3.869, is less than 7.815 and null hypothesis is accepted ;\n\n2(d)(i) 0.73 ; 1\n© Cambridge University Press & Assessment 2024 Page 8 of 9\n\n2(d)(ii) any four from: 4\nbreeding experiment (MAX 3):\n1 ref. to the two genes (B / b and R / r), are not linked ;\n2 idea that dominant alleles code for (functional) carrier, proteins / polypeptides ;\n3 idea that in fruit flies with dark-red eyes entry of guanine and tryptophan (into organelle) allows pigments to be\nproduced ;\n4 fruit flies with white eyes, (have the genotype) bbrr / homozygous recessive (for both genes)\nor\nfruit flies with dark-red eyes are, B_R ;\nchromatogram (MAX 3):\n5 fruit flies with dark-red eyes, have 4 pigments (in their eyes) ;\n6 fruit flies with white eyes, have no pigments (in their eyes) ;\n7 pigment 4 is drosopterin ;\n8 idea that, ommochrome / brown pigment, is insoluble (in the chromatography solvent)\nor\nidea that none of the pigments in the chomatogram are, ommochrome / brown pigment ;\n© Cambridge University Press & Assessment 2024 Page 9 of 9", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2024-March/ms/9700_m24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-march/9700_m24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m24_ms_52-p07.png", "../answer-assets/9700_m24_ms_52-p08.png", "../answer-assets/9700_m24_ms_52-p09.png" ] }, { "id": "9700-2024-mj-41-q01", "question_id": "9700-2024-mj-41-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "1(a) 3\nstage of respiration letter\nglycolysis B\nlink reaction D\nKrebs cycle D\noxidative phosphorylation C\n;;;\n3 marks if all four letters are correct\n2 marks if three letters are correct\n1 mark if one or two letters are correct\n\n1(b) any four from: 4\n1 oxygen is the, final / last / terminal, electron acceptor ;\n2 electron transport chain / ETC, stops ;\n3 less / no, protons / H+ / hydrogen ions, move,\ninto intermembrane space / across inner mitochondrial membrane ;\n4 less / no, proton / electrochemical, gradient ;\n5 less / no, protons move through ATP synthase ;\n6 less / no, recycling / regeneration, of, NAD / FAD ;\n\n1(c) any three from: 3\n1 lactate dehydrogenase ;\n2 less / no, pyruvate → lactate ;\n3 (so) less / no, NAD, regenerated / recycled ;\n4 (so) less / no, triose phoshate / TP, → pyruvate ;\n5 (so) less / no, ATP from substrate, linked / level, reactions / phosphorylation (in glycolysis) ;\n© Cambridge University Press & Assessment 2024 Page 6 of 15", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p06.png" ] }, { "id": "9700-2024-mj-41-q02", "question_id": "9700-2024-mj-41-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) 1 similarity: both involve a (signalling), chemical / ligand / molecule ; 2\n2 difference: endocrine chemical / hormone, travels in blood / circulatory system (but paracrine chemical travels by\ndiffusion) ;\n\n2(a)(ii) 1 (ACh) travels a short distance by diffusion ; 2\n2 across, synapse / synaptic cleft / neuromuscular junction ;\n\n2(b) any three conclusions from: 3\n1 palmitate-exposed cells, release / secrete, molecule / chemical / substance ;\n2 (this) molecule switches on stress genes in, new / other, muscle cells ;\n3 molecule is not, destroyed / denatured, by, boiling / high temperature ;\n4 (so) molecule is not a protein ;\n5 molecule is, lipid / lipid-soluble / hydrophobic / non-polar ;\n6 AVP ;\n\n2(c) any three from: 3\n1 less actin ;\n2 less myosin ;\n3 less troponin ;\n4 less tropomyosin ;\n5 fewer / smaller, sarcomeres / myofibrils / myofilaments / mitochondria / ribosomes ;\n6 less of other named protein ;\nQuestion Answer Marks", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p07.png" ] }, { "id": "9700-2024-mj-41-q03", "question_id": "9700-2024-mj-41-q03", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "3(a) any four from: 4\n1 protons / H+ ions, pumped, from guard cells / into guard cell wall ;\n2 ref. to negative potential (inside cell) or Cl – ions enter (cell) ;\n3 (voltage-gated) K+ channels open or K+ ions enter (guard) cells ;\n4 water enters cell, by osmosis / down water potential gradient ;\n5 (guard) cells, become turgid / swell / increase in volume ;\n© Cambridge University Press & Assessment 2024 Page 7 of 15\n\n3(b)(i) any two from: 2\n1 as abscisic acid concentration increases stomatal conductance decreases or negative correlation / inverse\ncorrelation / inversely proportional ;\n2 two sets of x y figures to support mp 1 with units (at least once) ;\n3 steep decrease in conductance to 100–150 ABA ;\n4 no / little, effect on conductance above 250–425 ABA ;\n\n3(b)(ii) any four from: 4\n1 ABA causes stomata to close ;\n2 ABA binds to receptor on guard cell ;\n3 Ca2+ ions, enter (guard) cells / act as 2nd messenger ;\n4 K+ ions leave (guard) cells ;\n5 water leaves so cells become, flaccid / less turgid ;\n6 AVP ;\n\n3(c) DNA / promoter ; 1\nQuestion Answer Marks", "source_pages": [ 7, 8 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p07.png", "../answer-assets/9700_s24_ms_41-p08.png" ] }, { "id": "9700-2024-mj-41-q04", "question_id": "9700-2024-mj-41-q04", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 15, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 (random / spontaneous) mutation gave resistance ;\n2 pathogen / disease / plague, was selection pressure ;\n3 mutation, gave selective advantage / was selected for / allowed crayfish to survive (plague) ;\n4 survivors / resistant crayfish, bred / reproduced / passed on mutation ;\n5 frequency of, allele / mutation, (for resistance) increased ;\n6 natural / directional, selection ;\n7 AVP ;\n\n4(b)(i) 1 (heat to) 90–98 °C so DNA, denatures / strands separate ; 4\n2 (cool to) 50–65 °C so primers, bind / base pair / anneal (to DNA) ;\n3 (heat to) 68–75 °C so, Taq / DNA, polymerase, makes DNA / (new) strand ;\n4 repeat cycles to amplify DNA ;\n\n4(b)(ii) used, a (named) database / bioinformatics ; 1\n© Cambridge University Press & Assessment 2024 Page 8 of 15\n\n4(c)(i) A ; 1\n\n4(c)(ii) (23) = 8 ; 1\n\n4(d)(i) (named) plasmid / vector (used) ; 3\n(containing) gene / DNA, for (green) fluorescent protein ;\n(containing) a (prokaryotic) promoter ;\n\n4(d)(ii) to act as a, marker / reporter, gene 1\nor\nto identify, recombinant / GM / transgenic, bacteria / organisms\nor\nto show expression of another transferred gene ;\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p08.png", "../answer-assets/9700_s24_ms_41-p09.png" ] }, { "id": "9700-2024-mj-41-q05", "question_id": "9700-2024-mj-41-q05", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "5(a)(i) A = stroma ; 2\nB = thylakoid, lumen / space ;\n\n5(a)(ii) 1 cyclic photophosphorylation ; 2\n2 ATP synth(et)ase ;\n\n5(a)(iii) 1 D = reduced NADP ; 3\n2 reduces / gives hydrogen to, glycerate (3) phosphate / GP ;\n3 forming, triose phosphate / TP ;\n\n5(b)(i) any three from: 3\nD1 rate of energy transfer, higher / highest, for tropical\nor\nrate of energy transfer, lower / lowest, for snow forest ;\nD2 paired data quote with units (at least once) ;\nS3 tropical forest has, high(er/est) temperature / hot(ter) ;\nS4 tropical forest has high(er/est) light, intensity / duration ;\nS5 temperature / light intensity, is a limiting factor (on photosynthesis) ;\n© Cambridge University Press & Assessment 2024 Page 9 of 15\n\n5(b)(ii) any three from: 3\n1 more, transpiration / water loss (from leaves) ;\n2 stomata shut reducing, carbon dioxide (entry) / gas exchange ;\n3 (so) carbon dioxide (concentration) is a limiting factor ;\n4 (grassland / desert) fewer plants / less plant cover / smaller plants ;\n5 (so smaller surface area) less light absorbed ;\n6 AVP ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p09.png", "../answer-assets/9700_s24_ms_41-p10.png" ] }, { "id": "9700-2024-mj-41-q06", "question_id": "9700-2024-mj-41-q06", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "6(a)(i) any one from: 1\n1 same / equal, size / length ;\n2 same, shape / position of centromere ;\n3 same banding pattern ;\n\n6(a)(ii) any three from: 3\n1 recessive / mutation = faulty / inactive / no, tyrosinase ;\n2 (melanocytes) do not produce, melanin / pigment ;\n3 ref. to skin / hair / iris ;\n4 AVP ;\n© Cambridge University Press & Assessment 2024 Page 10 of 15\n\n6(b) gametes (on Punnett square) 4\n1 BF Bf bF bf ;\nPunnett square\nBF Bf bF bf\nBBFF BBFf BbFF BbFf\nBF\nblack black black black\nBBFf BBff BbFf Bbff\nBf\nblack white black white\nBbFF BbFf bbFF bbFf\nbF\nblack black brown brown\nBbFf Bbff bbFf bbff\nbf\nblack white brown white\n2 correct offspring genotypes on Punnett square ;\n3 phenotypes matching genotypes ;\noffspring phenotype ratio\n4 9 black : 3 brown : 4 white ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p10.png", "../answer-assets/9700_s24_ms_41-p11.png" ] }, { "id": "9700-2024-mj-41-q07", "question_id": "9700-2024-mj-41-q07", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 8, "status": "available", "reason": null, "text": "7(a)(i) as mutation rate increases lifespan decreases ; 1\n\n7(a)(ii) any three from: 3\n1 high(er) mutation rate gives more, genetic diversity / genetic variation / alleles / chance of beneficial allele ;\n2 short(er) lifespan gives more generations (per year / per unit time) ;\n3 with, high(er) mutation rate / short(er) lifespan, they, adapt / evolve, better / more easily / faster ;\n4 mouse (and ferret) may, adapt / evolve, faster ;\n5 AVP ;\n© Cambridge University Press & Assessment 2024 Page 11 of 15\n\n7(b)(i) comparison: 2\nC1 genetic engineering faster / selective breeding slower ;\nany one reason from:\nR2 selective breeding occurs over (many) generations ;\nR3 all cows could be surrogate mothers for engineered embryos (giving large increase in allele frequency in one\ngeneration) ;\nR4 AVP ;\n\n7(b)(ii) any two from: 2\n1 (improve named) quality of, animal / milk ;\n2 (improve) quantity / yield, of milk ;\n3 AVP ;\nQuestion Answer Marks", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p11.png", "../answer-assets/9700_s24_ms_41-p12.png" ] }, { "id": "9700-2024-mj-41-q08", "question_id": "9700-2024-mj-41-q08", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 13, "status": "available", "reason": null, "text": "8(a) any three from: 3\n1 assess / categorise / rank, species, threat level / conservation status ;\n2 ref. to Red List (of Threatened Species)\n3 influence / advise, countries / governments / policy makers ;\n4 educate / raise awareness ;\n5 promote sustainable, use / management, of (natural) resources ;\n© Cambridge University Press & Assessment 2024 Page 12 of 15\n\n8(b) any six from: 6\nbiological species (concept)\n1 no / not separate species / same species ;\n2 as can, interbreed / breed together, to produce, fertile offspring / pizzly bears\nor\nthey are not reproductively isolated ;\nmorphological species (concept)\n3 yes / separate species / different species ;\n4 as have different, colours / mass / size / hump size ;\necological species (concept)\n5 yes / separate species / different species ;\n6 as have different, niches / diets / habitats ;\ngenetic / phylogenetic, species (concept)\n7 unsure / don’t know ;\n8 as no information about genetic similarity ;\n9 AVP ;\n\n8(c)(i) 2 3\nn  n \nG. hapalotricha = 0.194 and = 0.037 ;\n \nN N\n2\n n \ntotal = 0.272 ;\n \nN\nD = 0.728 ;\n\n8(c)(ii) undisturbed / higher D, has, larger / higher / more, (food), diversity / variation ; 1\n© Cambridge University Press & Assessment 2024 Page 13 of 15", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p12.png", "../answer-assets/9700_s24_ms_41-p13.png" ] }, { "id": "9700-2024-mj-41-q09", "question_id": "9700-2024-mj-41-q09", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 6, "status": "available", "reason": null, "text": "9(a) any two from: 2\ndiscontinuous continuous\n(forms / phenotypes / categories) (forms / phenotypes / categories) not distinct / not\ndistinct / discrete / categoric / do not overlap / do not form discrete / overlap / form a (gradual) range / include\na (gradual) range / no intermediates / two or few intermediates / many different forms / many values on a\ndifferent forms spectrum ;\nnot a normal distribution / few bars (on bar chart) normal distribution or normal / bell-shaped curve (on\ngraph) ;\nno / little, effect from environment some / large, effect from environment ;\nA genes only\n\n9(b) any two from: 2\n1 one / two, genes (control colour pattern) ;\n2 different alleles of a gene have a large effect ;\n3 multiple / three, alleles ;\n4 gene interaction / epistasis ;\n5 AVP ;\n\n9(c) any two from: 2\n1 temperature / food (supply) ;\n2 of larva / during larval development ;\n3 egg size / diet of mother / size of mother ;\n© Cambridge University Press & Assessment 2024 Page 14 of 15", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p14.png" ] }, { "id": "9700-2024-mj-41-q10", "question_id": "9700-2024-mj-41-q10", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 6, "status": "available", "reason": null, "text": "10 any six from: 6\n1 sucrose binds to, receptor protein / (chemoreceptor) cell surface receptor ;\n2 ref. to second messenger ;\n3 (chemoreceptor cell) Na+ entry / membrane depolarises ;\n4 receptor / generator, potential ;\n5 Ca2+ ions enter (chemoreceptor cell) ;\n6 (named) neurotransmitter vesicles, move towards / fuse with,\n(presynaptic) membrane ;\n7 (named) neurotransmitter, release / exocytosis, into (synaptic) cleft ;\n8 (named) neurotransmitter binds to receptor on, sensory neurone / postsynaptic membrane ;\n9 Na+ enters (through ligand-gated channel) → depolarisation ;\n10 ref. to threshold for action potential ;\n11 AVP ;\n© Cambridge University Press & Assessment 2024 Page 15 of 15", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_41-p15.png" ] }, { "id": "9700-2024-mj-42-q01", "question_id": "9700-2024-mj-42-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "1(a)(i) hypothalamus ; 1\n\n1(a)(ii) (changes in) water potential (of blood) ; A  1\n\n1(a)(iii) posterior pituitary (gland) ; 1\n\n1(b)(i) 61.5(%) ;; 2\n61.538461 allow one mark for not rounding to one decimal place\n\n1(b)(ii) any three from: 3\n1 (increase in ADH results in) aquaporins added to, cell surface membrane / luminal membrane / plasma membrane ;\n2 more water leaves, filtrate / collecting duct\nor\nmore water reabsorbed / more water enters blood or tissue fluid ;\n3 so urine, volume decreases / concentration increases ;\n4 AVP ; e.g. ADH binds to receptor / increase in permeability of (cell surface) membrane / ref. to water moving, down a\nwater potential gradient or by osmosis\nI descriptions\n© Cambridge University Press & Assessment 2024 Page 5 of 20", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p05.png" ] }, { "id": "9700-2024-mj-42-q02", "question_id": "9700-2024-mj-42-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "2(a) 1 genetic / genotype / alleles 3\nor\nexample ; mutation / crossing over / independent assortment / random fertilisation / random mating\n2 environmental\nor\nexample ; climate / disease / food availability / soil pH / selection pressure\n3 combination / interaction, of genes and environment\nor\nexample ; gene (expression) is modified by environment\n\n2(b)(i) any three from: 3\n1 formation of new species from, pre-existing species / common ancestor ;\n2 change in, characteristics / phenotypes ;\n3 over, time / generations ;\n4 natural selection ;\n5 changes in, gene pools / allele frequencies\nor\ngenetic drift ;\n© Cambridge University Press & Assessment 2024 Page 6 of 20\n\n2(b)(ii) any three from: 3\n1 compare sequences (of DNA) ;\n2 the more similar the sequences the more, closely related the species / recent the common ancestor ; ora\n3 over time mutations accumulate\nor\nless time fewer mutations occurred ;\n4 ref. to bioinformatics / software / database ;\n5 AVP ; e.g. molecular clock / constant rate of mutation\ne.g. mtDNA has no crossing over\ne.g. the percentage similarity can be used to build a phylogenetic tree\n© Cambridge University Press & Assessment 2024 Page 7 of 20", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p06.png", "../answer-assets/9700_s24_ms_42-p07.png" ] }, { "id": "9700-2024-mj-42-q03", "question_id": "9700-2024-mj-42-q03", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "3(a) (gene L has) four alleles / LV, LT, LR and Lr ; 1\nA a gene which has more than two alleles\n\n3(b) parental genotypes: LT LR x LT LR 4\ngametes: LT LR LT LR ;\noffspring genotypes: LT LT LT LR (LT LR) LR LR ;\noffspring phenotypes: dfm-a dfm-b (dfm-b) rufipennis ;\nlinked to genotypes\nratio of offspring phenotypes: 1 : 2 : 1 ;\naccept correct phenotype descriptions\n\n3(c) LT and LR ; 2\nLT and LR > LV > Lr ;\n\n3(d)(i) (female) LV Lr and (male) Lr Lr ; 2\nLV Lr (and LV Lr) ;\n\n3(d)(ii) there are similar numbers of male and female offspring produced 1\n(for each phenotype)\nor\nfemale metallic offspring are produced\nor\nif linked to X chromosome no female metallic offspring are produced ;\n\n3(d)(iii) chi-squared test ; A 2 1\n© Cambridge University Press & Assessment 2024 Page 8 of 20", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p08.png" ] }, { "id": "9700-2024-mj-42-q04", "question_id": "9700-2024-mj-42-q04", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 11, "status": "available", "reason": null, "text": "4(a) any five from: 5\n1 a gene codes for a protein which determines the phenotype ;\n2 F8 gene ;\n3 located on X chromosome / sex-linked ;\n4 ref. to recessive allele ;\n5 non-functioning factor VIII (protein)\nor\nless factor VIII (protein)\nor\nno factor VIII (protein) ;\n6 (so) blood does not clot quickly enough / excessive bleeding\noccurs (after an injury) ;\n7 link the phenotype to the genotype ;\ne.g. XF XF = normal female\nXF Xf = normal female\nXf Xf = affected female\nXF Y = normal male\nXf Y = affected male\n8 AVP ; e.g. prevents activation of thrombin / fibrinogen not converted to fibrin / ref. to mostly males affected / different\nmutations cause a range of severity of haemophilia\n© Cambridge University Press & Assessment 2024 Page 9 of 20\n\n4(b) any three from: 3\n1 lele is, homozygous recessive / two recessive alleles ;\n2 le (allele) / lele, codes for a non-functional enzyme ;\n3 no, active gibberellin / GA\n1\nor\nref. to gibberellin inactive ;\n4 no / less, cell elongation\nor\nno / less, stem elongation / increase in internodal length ;\n5 AVP ; e.g. ref. to GA 3β-hydroxylase / GA3-oxidase / last enzyme in the pathway that produces, active\ngibberellin / GA\n1\nle allele codes for alanine instead of threonine (in the enzyme)\n\n4(c) any three from: 3\n1 (DELLA proteins) bind to, PIF / transcription factor ;\n2 PIF / transcription factor, cannot bind to, DNA / promoter ;\n3 RNA polymerase cannot bind to promoter ;\n4 no transcription / mRNA not made ;\n© Cambridge University Press & Assessment 2024 Page 10 of 20", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p09.png", "../answer-assets/9700_s24_ms_42-p10.png" ] }, { "id": "9700-2024-mj-42-q05", "question_id": "9700-2024-mj-42-q05", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "5(a) 1 family history of, breast / ovarian, cancer ; 4\nplus any three from:\n2 (mutation causes) change of primary structure (of tumour suppressor protein) ;\n3 changes, folding / bonding / 3D shape / tertiary structure (of tumour suppressor protein) ;\n4 non-functional (tumour suppressor) protein formed ;\n5 DNA is not repaired / cells with damaged DNA do not die ;\n6 (so) increases number of mutations / mutations accumulate ;\n7 (some mutations) cause uncontrollable, cell division / mitosis (of breast cells) ;\n\n5(b) 1 only small amount of DNA available ; A gene 2\n2 amplify, DNA / (BRCA1) gene ;\n\n5(c) 6.1  104 ;; A 6.125  104 for two marks 2\nallow one mark for\n61 250\nor\n3.5107\n= 8.75  104 or 87 500\n400\n© Cambridge University Press & Assessment 2024 Page 11 of 20\n\n5(d) any two from: 2\nsupports:\n1 (women with BCRA1) have a higher probability of survival ; ora\n2 (for women with BRCA1) the probability of survival decreases less\nor\nthere is a smaller rate of decrease of probability of survival\nor\nbigger difference between the two groups over time for the probability of survival ;\nora\n3 data quote to show differences between the survival of the two groups at a particular time ;\nprobability of survival\ntime / months\nwith mutation without mutation\n0.975\n30 0.85\nrange 0.975 – 0.988\n60 0.95 0.75\n0.675\n90 0.85\nrange 0.675 – 0.688\n0.63\n120 0.75\nrange 0.613 – 0.625\n150 0.75 0.55\n0.7 / 0.70 0.475 / 0.474 / 0.47\n180\nrange 0.7 – 0.71 range 0.46 – 0.475\n4 study carried out for, a long time / 15 years ;\ndoes not support:\n5 no statistical test carried out / ref. to sample size ;\n© Cambridge University Press & Assessment 2024 Page 12 of 20", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p11.png", "../answer-assets/9700_s24_ms_42-p12.png" ] }, { "id": "9700-2024-mj-42-q06", "question_id": "9700-2024-mj-42-q06", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "6(a) an arrow through phospholipid layer in outer membrane and an arrow through phospholipid layer in inner membrane ; 1\nR arrows through proteins or A, B, C or D\n\n6(b) 1 D = ATP synthase / ATP synthetase ; R ATPase 7\n2 A, B and C = ETC / electron transport chain / electron carriers / electron acceptors ;\nplus any five from:\nrole of, ETC proteins / A, B and C\n3 electrons travel along ETC ;\n4 energy released ;\n5 (use energy released) to pump / actively transport, H+ / protons, into intermembrane space ;\n6 increases concentration of H+ / protons (in intermembrane space) / creates proton gradient ;\nrole of D\n7 H+ / protons, diffuse through, ATP synthase / D ;\n8 (from intermembrane space) to matrix ;\n9 synthesis of ATP from ADP and Pi ;\n10 chemiosmosis ;\n© Cambridge University Press & Assessment 2024 Page 13 of 20\n\n6(c) any three from: 3\n1 (named) enzyme for, Krebs cycle / link reaction ;\n2 ETC proteins / cytochromes / electron carriers / electron acceptors / A / B / C ;\n3 ATP synthase / D / described ;\n4 membrane / channel / transport / carrier / structural, proteins ;\n5 (make) tRNA / rRNA / ribosomes ;\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p13.png", "../answer-assets/9700_s24_ms_42-p14.png" ] }, { "id": "9700-2024-mj-42-q07", "question_id": "9700-2024-mj-42-q07", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "7(a)(i) 1 rate of oxygen produced / rate of photosynthesis, is low / stays constant 3\nor\nsmall decrease in, rate of oxygen produced / rate of photosynthesis ;\n2 light intensity was the limiting factor / AW ;\n3 (so) less / little, light energy absorbed / photolysis (of water) / photoactivation (of chlorophyll)/ light-dependent\nreactions / photophosphorylation ; R no light energy absorbed\n© Cambridge University Press & Assessment 2024 Page 14 of 20\n\n7(a)(ii) any three from: 3\n1 rate of oxygen produced / rate of photosynthesis, decreased ;\n2 two paired data quotes with units ;\ntemperature / °C rate of oxygen\nproduction / mm3 h–1\n30 4 / 4.00\n40 2.55\n50 0.65 (A 0.62-0.65)\n3 because, enzyme / ATP synthase / NADP reductase / oxygen evolving complex, denatured ; A rubisco\n4 change in active site / fewer ESCs ;\n\n7(b) any three from: 3\n1 light absorbed by, photosystem II / P680\nor\nphotoactivation / photoionisation (of chlorophyll) ;\n2 photolysis (of water) ;\n3 water-splitting enzyme / oxygen evolving complex ;\n4 water splits into protons, electrons and oxygen ; A equation\n© Cambridge University Press & Assessment 2024 Page 15 of 20", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p14.png", "../answer-assets/9700_s24_ms_42-p15.png" ] }, { "id": "9700-2024-mj-42-q08", "question_id": "9700-2024-mj-42-q08", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 15, "status": "available", "reason": null, "text": "8(a)(i) receptor ; 1\n\n8(a)(ii) intermediate neurone ; A relay neurone / motor neurone 1\n\n8(a)(iii) Schwann ; 1\n\n8(b) any four from: 4\ndifferences\nmyelinated neurone\n1 faster (impulse transmission) ; ora\nexplanation\n2 myelin (sheath), insulates (the axon) / prevents movement of ions ;\n3 nodes of Ranvier / gaps with no myelin sheath, have voltage-gated channels\nor\nnodes of Ranvier / gaps with no myelin sheath, allow movement of ions ;\n4 depolarisation / action potential, occurs only at nodes of Ranvier / gaps with no myelin sheath; ora\n5 action potentials jump from node to node / saltatory conduction ; ora\n6 longer local circuits / local circuits occur between nodes ; ora\n\n8(c)(i) 1 A voltage-gated and B ligand-gated / not voltage-gated 2\nor\nA opens in response to, depolarisation / arrival of an action potential\nand\nB opens in response to binding of, acetylcholine / neurotransmitter ;\n2 A for calcium ions and B for sodium ions ;\n© Cambridge University Press & Assessment 2024 Page 16 of 20\n\n8(c)(ii) any four from: 4\n1 no Ca2+ enter (presynaptic, knob / neurone) ;\n2 vesicles do not, move towards / fuse with, presynaptic membrane ;\n3 no, ACh / neurotransmitter, released\nor\nno exocytosis of, ACh / neurotransmitter ;\n4 ACh / neurotransmitter, does not bind to, receptor / ion channel B ;\n5 Na+ does not enter postsynaptic neurone / ion channel B does not open ;\n6 postsynaptic membrane not depolarised\nor\nno action potential generated\nor\nimpulse not transmitted ;\n\n8(c)(iii) any two from: 2\n1 inside more negative (charge)\nor\nmembrane hyperpolarised / membrane potential decreases / potential difference increases ;\n2 harder to / cannot, reach threshold ;\n3 no depolarisation of membrane / harder to depolarise membrane\nor\nno / fewer / harder to generate, action potentials / impulses ;\n© Cambridge University Press & Assessment 2024 Page 17 of 20", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p16.png", "../answer-assets/9700_s24_ms_42-p17.png" ] }, { "id": "9700-2024-mj-42-q09", "question_id": "9700-2024-mj-42-q09", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 8, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 not predated / predators killed (as toxic) ;\n2 eats / decreases numbers, of, native / local, species ;\n3 disrupts, food web / food chain / ecosystem ;\n4 can spread to other areas / numbers increase rapidly ;\n5 reduces biodiversity ;\n6 can cause extinction (in, native / local, species) ;\n7 competes (with native species) for, space / breeding areas / food / water / resources ;\n8 introduces / new, disease ;\n© Cambridge University Press & Assessment 2024 Page 18 of 20\n\n9(b) A eggs for ova / oocytes 4\nany four from:\n1 (females) given, hormones / FSH, to stimulate maturation of, ova / oocytes\nor\n(females) given, hormones / FSH, to stimulate superovulation ;\n2 ova / oocyte, collection / harvesting ;\n3 sperm added to, ova / oocytes\nor\nref. to fertilisation ;\n4 sperm from genetically distant male / AW ;\n5 embryos, checked / selected ;\n6 embryo placed into uterus ;\n7 some embryos can be frozen ;\n© Cambridge University Press & Assessment 2024 Page 19 of 20", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p18.png", "../answer-assets/9700_s24_ms_42-p19.png" ] }, { "id": "9700-2024-mj-42-q10", "question_id": "9700-2024-mj-42-q10", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "10(a) negative feedback ; 1\n\n10(b) any three from: 3\n1 (blood) glucose concentration decreases due to increased respiration\nor\n(blood) glucose concentration decreases due to glucose used to generate ATP for, muscle contraction /\nmovement / exercise ;\n2 glucagon released (from pancreas) ;\n3 glucagon acts on liver cells ;\n4 glycogenolysis occurs / description ;\n5 glucose released into blood so (blood) glucose concentration, increases / returns to set point ;\n6 AVP ; e.g. gluconeogenesis / ref. cell signalling\n\n10(c)(i) A – gluconic acid / gluconolactone ; 2\nB – chromogen ;\n\n10(c)(ii) any two from: 2\n1 measures, current / direct, blood glucose concentration ;\n2 accurate reading / quantitative / numerical / digital ;\n3 reusable ;\n4 AVP ; e.g. can use regularly / convenient digital store of data / connected to phone or surgery\n© Cambridge University Press & Assessment 2024 Page 20 of 20", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_42-p20.png" ] }, { "id": "9700-2024-mj-43-q01", "question_id": "9700-2024-mj-43-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "1(a) A – G protein ; 3\nB – cyclic AMP / cAMP ;\nC – aquaporin ; I water channel\n\n1(b) any three from: 3\n1 dehydration / not drinking enough water ;\n2 ingesting salty food / description ;\n3 more, ions / glucose / amino acids / solute, (in blood) ;\n4 sweating / perspiration / evaporation (of water) ;\n5 AVP ; e.g. disease where ADH is not, made / secreted\n\n1(c) any two from: 2\n1 increase in / large, urine volume\nor\nmore frequent urination\nor\ndilute / less concentrated, urine ;\n2 fatigue ;\n3 feelings of thirst / dry mouth ;\n4 AVP ; e.g. dehydration\nchange in blood pressure\n© Cambridge University Press & Assessment 2024 Page 6 of 20\n\n1(d) any two from: 2\n1 few / no, aquaporins added to membrane / P ;\n2 reduced / low, permeability of, membrane / P, to water ; R impermeable to water\n3 less water moves through, membrane / P ;\necf for mp1 if C named as water channels in 1(a)\n\n1(e) (gene is on X chromosome) 2\nX (chromosome with recessive allele) inherited from mother ;\nY (chromosome) inherited from father ;\n© Cambridge University Press & Assessment 2024 Page 7 of 20", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p06.png", "../answer-assets/9700_s24_ms_43-p07.png" ] }, { "id": "9700-2024-mj-43-q02", "question_id": "9700-2024-mj-43-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 7, "status": "available", "reason": null, "text": "2(a) 3\ndescription of phenotypic variation cause of\nvariation\nTomato plants grown in a glasshouse and grown outside V + V\nG E\nvary in the yield of tomatoes they produce. Seventeen\ngenes associated with tomato yield have been identified.\nNew strawberry plants from the variety called Sweet Ann are V\nE\nmade by asexual reproduction. The new plants grow to\ndifferent sizes and produce different numbers of fruit.\nThe domestic cat has a blood group system with three V\nG\npossible blood types: A, B and AB. The blood types are\ndetermined by antigens present on the cell surface\nmembrane of red blood cells.\nOver 50 genes have variants that are associated with V + V\nG E\nexcessive weight-gain in humans. Other risk factors for\nexcessive weight-gain include diet and exercise.\nResting heart rate in humans varies between different V + V\nG E\nindividuals. Some factors that influence resting heart rate\ninclude: biological sex, family history of heart disease,\nnumber of cigarettes smoked, medication taken.\nfive correct = 3 marks ;;;\nfour or three correct = 2 marks\ntwo or one correct = 1 mark\n\n2(b) mutation ; 1\n© Cambridge University Press & Assessment 2024 Page 8 of 20\n\n2(c) any three from: 3\n1 crossing over ;\n2 independent / random, assortment ;\n3 random, fusion of gametes / fertilisation ;\n4 random mating ;", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p08.png", "../answer-assets/9700_s24_ms_43-p09.png" ] }, { "id": "9700-2024-mj-43-q03", "question_id": "9700-2024-mj-43-q03", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 12, "status": "available", "reason": null, "text": "3(a)(i) Ttdd and TTdd ; 1\n\n3(a)(ii) 13:3 ; 1\n\n3(a)(iii) epistasis ; 1\n\n3(a)(iv) any five from: 5\n1 dominant allele / T / D, results in a functional protein ;\n2 two recessive alleles / tt / dd, results in a non-functional protein ;\n3 T could code for an enzyme ;\n4 (so enzyme catalyses) production of, malvidin / pigment ;\n5 D could code for an inhibitor ;\n6 (inhibitor) binds to enzyme (coded for by) gene T/t ;\n7 (so) reaction to produce, malvidin / pigment, does not occur ;\n8 protein (coded by T / t) could be a transcription factor ;\n9 transcription factor allow the production of enzyme (needed in the metabolic pathway) ;\n10 protein (coded by D/d) could cause the inhibition of transcription factor ;\n© Cambridge University Press & Assessment 2024 Page 9 of 20\n\n3(b) any four from: 4\n1 located on X chromosome / sex-linked ;\n2 ref. to recessive allele ;\n3 non-functioning, factor VIII / protein\nor\nless, factor VIII / protein\nor\nno, factor VIII / protein ;\n4 (so) blood does not clot quickly enough / excessive bleeding occurs (after an injury) ;\n5 link the phenotype to the genotype ;\ne.g. XFXF = normal female\nXFXf= normal female\nXfXf= affected female\nXFY = normal male\nXfY = affected male\n6 AVP ; e.g. prevents activation of thrombin / fibrinogen not converted to fibrin / ref. to mostly males affected /different\nmutations cause a range of severity of haemophilia", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p09.png", "../answer-assets/9700_s24_ms_43-p10.png" ] }, { "id": "9700-2024-mj-43-q04", "question_id": "9700-2024-mj-43-q04", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a)(i) restriction endonuclease 4\n1 cuts, DNA / plasmid ;\nDNA ligase\n2 joins DNA with the plasmid ;\nDNA polymerase\n3 forms dsDNA\nor\nmakes a complementary DNA strand ;\nreverse transcriptase\n4 uses mRNA (as a template) to make, cDNA / complementary (ss)DNA ; R converts\n© Cambridge University Press & Assessment 2024 Page 10 of 20\n\n4(a)(ii) any three from 3\n1 for transcription factor(s) to bind ;\n2 for RNA polymerase to bind ;\n3 (so) gene is, expressed / switched on / activated / transcribed ;\n4 to, increase / control, transcription of the, gene of interest / marker gene;\n5 to cause transcription with a specific environmental change ; A inducible promoter\n6 AVP ; e.g. choose promoter to give transcription in, all tissues / all developmental stages\n\n4(b) plasmid X - no insulin because the gene is, inserted backwards / the wrong way around ; 3\nplasmid Y - produces insulin because the gene, is inserted the correct way around / AW ;\nplasmid Z - no insulin because, the gene was not inserted / the plasmid closed up / it is a non-recombinant plasmid ;", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p10.png", "../answer-assets/9700_s24_ms_43-p11.png" ] }, { "id": "9700-2024-mj-43-q05", "question_id": "9700-2024-mj-43-q05", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 11, "status": "available", "reason": null, "text": "5(a) crossing over ; A chiasma formation 1\n© Cambridge University Press & Assessment 2024 Page 11 of 20\n\n5(b)(i) any three from: 3\n1 mutation occurred a long time ago\nor\nsomeone in original population had mutation\nor\nmutation in common ancestor ;\n2 ref. to. founder effect ;\n3 (original / current) population is small ;\n4 idea that much of the population is closely related\nor\nsmall gene pool / low genetic diversity ; A inbreeding\n5 ref. to isolated (population) ;\n6 (caused) increase in frequency of, mutation / 999del5 / BRCA2 allele ;\n\n5(b)(ii) any three from: 3\n1 reduce worry if negative ;\n(if positive)\n2 lifestyle changes / described ;\n3 early treatment / breast removal / can have frequent checks ;\n4 informed decision about having children ;\n5 ref. to counselling ;\n6 could lead to lower death rates from breast cancer ;\n© Cambridge University Press & Assessment 2024 Page 12 of 20\n\n5(b)(iii) any one from: 1\n1 only screen for mutations that occur with high frequency in a population (as opposed to hundreds of mutations) ;\n2 cost effective ;\n3 early diagnosis / early treatment / targeted treatment ;\n4 identifies mutation known to increase the risk of developing breast cancer (as opposed to a neutral mutation) ;\n5 could lead to lower death rates from breast cancer ;\n\n5(c)(i) any two from: 2\n1 it, inserted / deleted / replaced, DNA (in, Lcn2 / regulatory sequence) ;\n2 (so) transcription of, Lcn2 / gene, prevented ;\n3 (replaced mutated section of DNA) with correct sequence ;\n\n5(c)(ii) only specific, sites / sequences, (on DNA targeted) 1\nor\ntarget site on DNA only found in Lcn2 ;", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p11.png", "../answer-assets/9700_s24_ms_43-p12.png", "../answer-assets/9700_s24_ms_43-p13.png" ] }, { "id": "9700-2024-mj-43-q06", "question_id": "9700-2024-mj-43-q06", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "6(a) any three from: 3\n1 need to open to obtain carbon dioxide for, photosynthesis / Calvin cycle ;\n2 need to close to prevent water loss by, transpiration / described ;\n3 can close, at night / when dark, (to save water) as no photosynthesis ; AW\n4 must close to prevent water loss when, high light intensity / high temperatures / high wind speed / water stress / drought\nconditions ;\n© Cambridge University Press & Assessment 2024 Page 13 of 20\n\n6(b) any six from: 6\n1 H+, pumped / moved by active transport, out (of guard cells) ;\n2 decrease in H+ inside (of guard cells) / proton gradient set up / AW ;\n3 K+ channels open / K+ enters (guard cells) ;\n4 water potential (in guard cells), decreases / lowers / becomes more negative ;\n5 water enters (guard cells) by, osmosis / down the water potential gradient ;\n6 cells, expand / become (more) turgid ;\n7 outer wall thinner to allow (more), stretching / bending\nor\ninner wall thicker to allow less, stretching / bending ;\n8 AVP ; e.g. light activates, ATP production / proton pump sentry of, chloride ions / Cl- (in addition to K+) / entry of water\nvia aquaporins\nmax 3 if stomatal closure described\n© Cambridge University Press & Assessment 2024 Page 14 of 20", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p13.png", "../answer-assets/9700_s24_ms_43-p14.png" ] }, { "id": "9700-2024-mj-43-q07", "question_id": "9700-2024-mj-43-q07", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "7(a)(i) 1\nlight intensity total CO uptake after rate of photosynthesis\n2\n/ lux 20 seconds / μmols-1\n/ μmol\n0 0 0.0\n3 20 10\n6 44 22 ;\n9 72 36\n12 80 40\n\n7(a)(ii) five points plotted correctly ; 3\nbest fit curve drawn for plots ;\ncurve levels off from 12 lux to 18 lux\nor\ncurve continues up at smaller gradient ;\n\n7(a)(iii) curve levels off from 12 lux to 18 lux 2\n1 because light intensity no longer limiting ;\n2 temperature / carbon dioxide concentration, now limiting ;\n© Cambridge University Press & Assessment 2024 Page 15 of 20\n\n7(b) any four from: 4\n1 electrons, excited / emitted / described ;\n2 electrons travel along ETC and energy released ;\n3 (use energy released) to pump H+ into thylakoid, space/ lumen ;\n4 increases concentration of H+ / protons (in thylakoid space / lumen) / creates proton gradient ;\n5 H+ / protons, diffuse through ATP synthase ;\n6 (from thylakoid space) to stroma ;\n7 chemiosmosis ;\n© Cambridge University Press & Assessment 2024 Page 16 of 20", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p15.png", "../answer-assets/9700_s24_ms_43-p16.png" ] }, { "id": "9700-2024-mj-43-q08", "question_id": "9700-2024-mj-43-q08", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "8(a) any four from: 4\nouter / inner membranes\n1 allow entry of, oxygen for oxidative phosphorylation / pyruvate for link reaction ; I Krebs cycle\n2 allow exit of carbon dioxide from, Krebs cycle / link reaction ;\n3 compartmentalisation / described ;\ninner membrane\n4 (location of) ETC to release energy to pump protons into intermembrane space ;\n5 (location of) ATP synthase for production of ATP ;\n6 cristae / infoldings, to increase surface area for many, ETCs / ATP synthases ;\n7 impermeable to, hydrogen ions / protons, to maintain proton gradient\nor\nimpermeable to, hydrogen ions / protons, to maintain, high H+ concentration in intermembrane space ;\n8 site of, oxidative phosphorylation / chemiosmosis ;\n\n8(b)(i) any two from: 2\n1 ref. to cells, metabolic rate / energy needs ;\n2 in cells about to undergo, mitosis / cell division ;\n3 AVP ; e.g. to replace damaged mitochondria\n\n8(b)(ii) hydrolysed / bond broken, (to release energy) 1\nor\nG proteins bind to GTP rather than to ATP ;\n\n8(c) 1 degraded / broken down by, lysosomes / hydrolytic enzymes ; 2\n2 components of breakdown / AW, used to produce new mitochondria ;\n© Cambridge University Press & Assessment 2024 Page 17 of 20", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p17.png" ] }, { "id": "9700-2024-mj-43-q09", "question_id": "9700-2024-mj-43-q09", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 10, "status": "available", "reason": null, "text": "9(a)(i) 367 (%) ;; 2\nallow 1 mark for:\n(738540)\n 100\n540\nor\n36.66666667\n\n9(a)(ii) any four from: 4\n1 increase in temperature / global warming ;\n2 sea levels increase ;\n3 habitat change / example ; e.g. forest fires / ocean acidification\n4 food web / food chain / ecosystem, disrupted ;\n5 change in biodiversity ;\n6 ref. to extinction ;\n7 AVP ;\n© Cambridge University Press & Assessment 2024 Page 18 of 20\n\n9(b) any four from: 4\n1 may have future use ;\n2 aesthetic / ethical / cultural, reasons ;\n3 medical uses / example ;\n4 ecotourism ;\n5 idea of maintaining stability in, ecosystems / food chains / food webs ;\n6 resource material ; e.g. wood for building / fibres for clothes / food (for humans) / agriculture\n7 maintain / increase, gene pool / genetic diversity ;\n8 ref. to soil stability / desertification ;", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p18.png", "../answer-assets/9700_s24_ms_43-p19.png" ] }, { "id": "9700-2024-mj-43-q10", "question_id": "9700-2024-mj-43-q10", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "10(a) 2\nK ;\nA ;\n© Cambridge University Press & Assessment 2024 Page 19 of 20\n\n10(b) any four from: 4\n1 sodium (ion) channels open\nor\nNa+ enters (axon) ;\n2 (so) membrane depolarised ;\n3 ref. to threshold (potential) reached (for action potential to occur) ;\n4 potassium (ion) channels open\nor\nK+ moves out (of axon) ;\n5 (causes) repolarisation (of membrane) ;\n6 ref. to hyperpolarisation (of membrane) ;\n7 return to resting potential ;\n8 AVP ; e.g. entry of sodium ions causes more sodium channels to open\n\n10(c) any four from: 4\ndescription\n1 myelinated axon / myelination, produces faster transmission speed (than unmyelinated) ;\n2 a larger the diameter (for unmyelinated) results in a faster transmission speed ; ora\n3 myelination has a greater effect on transmission speed than axon diameter ;\nexplanation\n4 (myelinated faster due to) saltatory conduction\nor\naction potential jumps from node (of Ranvier) to node ;\n5 axons with wider diameter have, less ion leakage / larger surface area / lower resistance ;\n© Cambridge University Press & Assessment 2024 Page 20 of 20", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_43-p19.png", "../answer-assets/9700_s24_ms_43-p20.png" ] }, { "id": "9700-2024-mj-51-q01", "question_id": "9700-2024-mj-51-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "1(a)(i) wind speed ; 1\n\n1(a)(ii) any six from: 6\n1 method to use fan(s), to obtain a minimum of five different wind speeds ;\n2 ref. to standardised variable for using the fan ;\n3 use a method to maintain, same / stated, temperature ;\n4 use a method to maintain, same / stated, light intensity ;\n5 at each wind speed, measure / note / record / AW, the initial mass and final mass, in a fixed time ;\n6 idea of equilibration / acclimatisation, of, plant / Japanese spiraea / apparatus ;\n7 use at least three measurements for each wind speed and calculate a mean ;\n8 safety comment with hazard and precaution ;\nhazard risk precaution\nJapanese spiraea / plant irritant / allergy gloves / mask / PPE\nsoil biohazard / pathogens / allergy gloves / mask / PPE\nI irritant\nfan hair / clothing / AW, trapped in fan method to, control loose,\nhair / clothing / AW\n9 method for measuring wind speed ;\n10 idea of replacing water lost from plant (before each new measurement) ;\n© Cambridge University Press & Assessment 2024 Page 5 of 11\n\n1(a)(iii) as wind speed, increases: 1\nrate of transpiration - increases\nor\ndecrease in mass, in fixed / stated time - increases\nor\nrate of decrease in mass - increases\nor\ntime taken, for a fixed decrease in mass - decreases ; ora\n\n1(b)(i) 26.3 ; 1\n\n1(b)(ii) any one from: 1\n1 use, same / stated, size of (blue) cobalt chloride paper ;\n2 idea of use a (pink) colour standard (to determine end point) ;\n3 idea of measure different positions on (lower) surface of leaf ;\n4 idea of unbiased selection of, leaves / leaf position ;\n© Cambridge University Press & Assessment 2024 Page 6 of 11", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_51-p05.png", "../answer-assets/9700_s24_ms_51-p06.png" ] }, { "id": "9700-2024-mj-51-q02", "question_id": "9700-2024-mj-51-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 14, "status": "available", "reason": null, "text": "2(a) any three from: 3\n1 light intensity ;\n2 duration / hours / AW, of light ;\n3 volume, of water (added to soil) ;\n4 type / pH, of soil ;\n5 mineral (ion), concentration (in soil) ;\n6 humidity ;\n7 carbon dioxide concentration ;\n\n2(b) (high mean temperature leads to) lower / AW (mean stomatal conductance), in both isohydric and anisohydric (species) ; 1\nora\n© Cambridge University Press & Assessment 2024 Page 7 of 11\n\n2(c) any four from: 4\nconclusion:\n1 (water stress leads to) lower / AW, (mean stomatal) conductance in isohydric and anisohydric (species) ; ora\nexplanation:\n2 idea that (lower stomatal conductance when exposed to water stress indicates that) water loss (by transpiration) is\nreduced ;\nconclusion:\n3 isohydric (species exposed to water stress and a high temperature) increase (mean stomatal) conductance\nor\nincreased (mean stomatal) conductance for isohydric (species exposed to water stress and a high temperature) is\n(statistically) significant ;\nexplanation:\n4 idea that (increased mean stomatal conductance in isohydric species exposed to water stress and a high temperature)\nhas a cooling effect ;\nconclusion:\n5 anisohydric (species exposed to water stress and a high temperature) do not change (mean stomatal) conductance\nor\nchange / difference / decrease / AW, in (mean stomatal) conductance for anisohydric (species exposed to water stress\nand a high temperature) is not (statistically) significant ;\nexplanation:\n6 idea that (unchanged mean stomatal conductance in anisohydric species when exposed to water stress and a high\ntemperature) to allow carbon dioxide uptake (for photosynthesis) ;\nconclusion:\n7 paired data quote to support conclusion ;\n© Cambridge University Press & Assessment 2024 Page 8 of 11\n\n2(d)(i) idea that there is no difference between the (mean) percentage of leaves that were dead on (young trees from) isohydric 1\nspecies and (young trees from) anisohydric species ;\n\n2(d)(ii) 1883 ; 2\nt = (190 – 35) / 8231 ;\n\n2(d)(iii) 1 calculated value of, t /1883, is less than, 2011 / critical value (at p = 0.05) 3\nor\ncalculated value of, t /1883, is less than, 2682 / critical value (at p = 0.01) ; ora\n2 null hypothesis is accepted (at p = 0.05 / p = 0.01) ;\n3 there is no significant difference (at p = 0.05 / p = 0.01) ;\nQuestion Answer Marks", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_51-p07.png", "../answer-assets/9700_s24_ms_51-p08.png", "../answer-assets/9700_s24_ms_51-p09.png" ] }, { "id": "9700-2024-mj-51-q03", "question_id": "9700-2024-mj-51-q03", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 6, "status": "available", "reason": null, "text": "3(a)(i) (human volunteer / person and) no (mosquito) repellent / spray 1\nor\n(human volunteer / person and) water (spray) ;\nor\n(human volunteer / person and) solvent (from repellent / spray) ;\n© Cambridge University Press & Assessment 2024 Page 9 of 11\n\n3(a)(ii) named risk and matching precaution ; 1\nrisk precaution\nmosquitoes take blood meal (from scientist) protective clothing / gloves / masks / PPE\nor\nmosquitoes bite (scientist)\nmosquitoes transmit, disease / pathogen / yellow protective clothing / gloves / masks / PPE\nfever / AW use, disease / pathogen, free mosquitoes\nvaccine (against yellow fever)\n(mosquito) repellent / spray / solvent, protective clothing / gloves / masks / PPE\nallergy / irritant / toxic\n© Cambridge University Press & Assessment 2024 Page 10 of 11\n\n3(b) any four from: 4\n1 98% DEET is effective (at repelling mosquitoes) ;\n2 idea that standard error / SE, overlap for 98% DEET and lemon eucalyptus oil, so these mosquito repellents are equally\neffective / no significant difference between these mosquito repellents ;\n3 idea that lemon eucalyptus oil is, (slightly) more effective / equally effective (as 98% DEET), but, has a low\nconcentration (of chemical) / might be safer\nor\nidea that lemon eucalyptus oil is, (slightly) more effective / equally effective, (as 98% DEET) but DEET is,\ntoxic / irritant / harmful ;\n4 idea that not true for all concentrations of DEET / 40% (concentration) DEET is much less effective ; ora\n5 no statistical test carried out ;\n6 only one human volunteer tested ;\n7 idea that some mosquitoes are still attracted to the human volunteer (when using 98% DEET) ;\n8 idea that mosquitoes used / Aedes aegypti, do not transmit malaria ;\n9 idea that mosquitoes were not able to, take a blood meal from / bite, the human volunteer / investigation only measured\nattraction of mosquitoes (to the human volunteer) ;\n© Cambridge University Press & Assessment 2024 Page 11 of 11", "source_pages": [ 9, 10, 11 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_51-p09.png", "../answer-assets/9700_s24_ms_51-p10.png", "../answer-assets/9700_s24_ms_51-p11.png" ] }, { "id": "9700-2024-mj-52-q01", "question_id": "9700-2024-mj-52-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 19, "status": "available", "reason": null, "text": "1(a)(i) species of tree 1\nor\ntype of tree ;\n\n1(a)(ii) any two from: 2\n1 (same) number of / 3, plantations for each tree species ;\n2 (same) size/area of, plot/(sampling)area / 36 m x 36 m / 1296m2 ;\n3 (same / used a) belt transect (same method in all plots/plantations) ;\n4 (same) months / seasons (of the year)\nor\nsampling at the same times ;\n© Cambridge University Press & Assessment 2024 Page 6 of 12\n\n1(b) any five from: 5\nusing a belt transect:\n1 use of tape / line / string, and quadrat (to create belt transect) ;\n2 selecting a start point for the, transect / placement of tape / line / string\nor\nall transects same length, in plots / plantations / repeats ;\n3 same (size) quadrat ;\n4 sample at / use quadrat at, regular intervals / stated distances along the, tape / line / string / transect\nor\ncontinuous belt transect ;\ncollecting data:\n5 method to identify each of the plant (species in the quadrat) ;\n6 count / record / note the number of (individuals), each plant species (n) (in each quadrat / at each sampling point)\nor\nestimate percentage (%) cover of each plant species (in each quadrat) ;\n7 use at least 3 different transects (in each plot) ;\n8 named hazard and risk and precaution ;\ne.g. (see table below)\n© Cambridge University Press & Assessment 2024 Page 7 of 12\n\n1(b)\nhazard risk preca ution\nplants / fungi falling trees / branches hard hat\nthorns gloves / goggles / mask / long trousers / PPE\nirritant / allergy antihistamines / cover skin / first aid equipment\ni nfection (spores)\n(named) bites / infection / attack antivenom / antihistamine / trained, professionals /\nanimal(s) / stings / allergy medics, available / insect\nparasite repellent / gloves / goggles / mask\n/ PPE / cover skin\nplantation trip hazard correct footwear / watch where you are walking / use\nterrain walking sticks\ngetting lost work in group / maps / use GPS / guide\npoachers being attacked / shot trained, professionals/ medics, available\n\n1(c) any one from: 1\n(does not support)\n1. acacia and mango have the same means\nor\nacacia and mango have similar, D values / index\nor\nmango and invasive species have overlapping, D values / index / means +/- SD ;\n(does support / partially support)\n2. sal tree has the highest, D value / index / mean\nor\nsal tree has greater, D values / Index / mean, than both alien species ;\n© Cambridge University Press & Assessment 2024 Page 8 of 12\n\n1(d)(i) 2\nconcentration volume of stock volume of (distilled)\n/ mg cm-3 solution / cm3 water / cm3\n7.5 37.5 12.5 ;\n2.5 12.5 37.5 ;\n\n1(d)(ii) 1 correct processes and correct figures ; 3\n2 (correct) answer to 3 significant figures ; ecf if mp1 is incorrect\n3 decrease / minus (number) ;\n© Cambridge University Press & Assessment 2024 Page 9 of 12\n\n1(e) any three from: 3\nimprovement impact\n1 More, intermediate / smaller values / intervals better idea of the, trend / pattern / effect ;\nappropriate examples accepted\n2 exclude anomalous results improve reliability ;\n3 repeat reading for 2.5 / 5.0 / 7.5 mg cm-3 (any of check the anomaly / improve reliability ;\nthese 3 might be anomalous)\n4 repeat investigation at least twice better idea of trend / improve reliability /\nor reduce effect of anomalies ;\nrepeat with more marigolds\n5 (calculate) standard error / standard check for significance (difference between the\ndeviation / confidence intervals / means) / checking accuracy ;\nstatistical analysis\n6 use marigold clones exclude genetic effects / improve validity ;\n7 use Vernier calliper more precise measurements ;\n8 measure the mass of all the roots improve reliability ;\n\n1(f) any two from: 2\n1 (same) mass of soil ;\n2 sample from same depth ;\n3 sampled at the same time ;\n4 sample from same, distance from roots / position in the pot ;\n© Cambridge University Press & Assessment 2024 Page 10 of 12", "source_pages": [ 6, 7, 8, 9, 10 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_52-p06.png", "../answer-assets/9700_s24_ms_52-p07.png", "../answer-assets/9700_s24_ms_52-p08.png", "../answer-assets/9700_s24_ms_52-p09.png", "../answer-assets/9700_s24_ms_52-p10.png" ] }, { "id": "9700-2024-mj-52-q02", "question_id": "9700-2024-mj-52-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "2(a) 1 correct counting / correct number of divisions / 28 ± 2 ; 3\n2 for correct conversion(s) to micrometres ;\n3 correct answer / 8.96 / 8.32–9.6 ;\n\n2(b)(i) measure the, widest / narrowest / longest, part of the each nucleus ; 1\n\n2(b)(ii) any one from: 1\n1 (same) magnification /  400 ;\n2 (same) number of / 100 nuclei (measuring) per, person ;\n3 (sample from / same) thyroid / gland ;\n4 same / one, scientist (measuring the diameter) ;\n5 idea that: type of tumour cell is unknown ;\n\n2(b)(iii) there is no difference, in / between the (mean) nuclear diameters of, the Pap-stained cells and H&E- stained cells ; 1\n\n2(b)(iv) accept null hypothesis 1\nor\nthere is no significant difference ;\n\n2(b)(v) state 2\n1 idea that this technique can be used to distinguish between benign and malignant cells\nor\nthe mean nuclear diameter of benign cells is smaller than in malignant cells / ora ;\nexplain\n2 mean  2 SE, do not overlap\nor\nthere is a significant difference in the mean nuclear diameters of benign cells and malignant cells ;\n© Cambridge University Press & Assessment 2024 Page 11 of 12\n\n2(b)(vi) disadvantages 2\n time consuming (prepping / counting / measuring)\n labour intensive\n shortage of skilled scientists\n invasive\n only thyroid / one tissue, used\n human error – due to, small values / very close values / large numbers counted\nimpact:\n infection / bleeding\n pain\n tissue damage\n metastasis\n anxiety\n delayed treatment\n unnecessary treatment\n idea of misdiagnosis\n possibly not feasible on large scale\n may not be true of other tumours\n© Cambridge University Press & Assessment 2024 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_52-p11.png", "../answer-assets/9700_s24_ms_52-p12.png" ] }, { "id": "9700-2024-mj-53-q01", "question_id": "9700-2024-mj-53-q01", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 19, "status": "available", "reason": null, "text": "1(a)(i) independent variable 1\ntype of blood vessel / artery and vein\nand\ndependent variable\nmass required to break (the blood vessel) ;\n© Cambridge University Press & Assessment 2024 Page 6 of 11\n\n1(a)(ii) any six from: 6\n1 method to cut the blood vessel ;\n2 method to measure blood vessel of, same / stated, length / AW ;\n3 idea of discard samples that are damaged ;\n4 idea of waiting (to see if the blood vessel breaks) before adding the next (10 g) mass ;\n5 use, artery and vein / blood vessels, from the same source ;\n6 add (10 g) masses, to the mass hanger, until the blood vessel breaks ;\n7 idea of measuring mass of mass hanger / including mass of mass hanger ;\n8 for each type of blood vessel, measure / note / record / AW, (total) mass when the blood vessel broke ;\n9 use at least three measurements for each type of blood vessel and calculate a mean ;\n10 safety comment with hazard and precaution ;\nhazard risk precaution\nknife / scalpel injury cut away from hand\nblood vessels biohazard / pathogens / allergy gloves / mask / PPE /\nuse disinfectant / wash hands\nmass hanger falling injury suitable precaution to prevent injury\n11 idea of repeat procedure with smaller mass intervals near to breaking mass ;\n© Cambridge University Press & Assessment 2024 Page 7 of 11\n\n1(b)(i) 2\nmass added / g length of vein / mm percentage increase in\nlength of ring of vein\n0 21 0\n10 36 71\n20 38 81\n30 40 90\n40 41 95\n50 41 95\nthree values correct ;;\none or two correct max 1\n\n1(b)(ii) 1 to make a valid comparison (with other blood vessels / veins) ; 1\n2 allows comparison as, initial / starting, length (of veins) is, not constant / AW ;\n\n1(b)(iii) 1 correct orientation for axes and linear scale ; 3\n2 axes labelled and units;\n3 all points plotted correctly and line drawn accurately ;\n\n1(b)(iv) 1 curve for artery starts at same point as the vein ; 2\n2 curve for artery below curve for vein and does not intersect ;\n© Cambridge University Press & Assessment 2024 Page 8 of 11\n\n1(b)(v) any two from: 2\n1 starts at, same point / origin, as using percentage increase ;\n2 (muscular) arteries have a thicker, wall / tunica media / muscle layer (than the vein)\nor\n3 (muscular) arteries have more (smooth) muscle (than the vein) ;\n4 idea of (muscular artery) withstands more (blood) pressure so stretches less (than the vein) ;\n\n1(b)(vi) any two from: 2\n1 use smaller mass intervals ;\n2 extend the range of the masses added ;\n3 use a, force meter / Newton meter / data logger / AW, (to apply force) ;\n4 attach a, pointer / fiducial mark, to the ring of blood vessel (to improve length measurement / removing parallax) ;\n5 use, same / stated, width of blood vessel ;\n© Cambridge University Press & Assessment 2024 Page 9 of 11", "source_pages": [ 6, 7, 8, 9 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_53-p06.png", "../answer-assets/9700_s24_ms_53-p07.png", "../answer-assets/9700_s24_ms_53-p08.png", "../answer-assets/9700_s24_ms_53-p09.png" ] }, { "id": "9700-2024-mj-53-q02", "question_id": "9700-2024-mj-53-q02", "subject": "9700", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "2(a) 1 cm3 of stock solution to 149 cm3 of distilled water ; 2\n(dilution factor is) 150 ;\n\n2(b) any one from: 1\n1 measure from, top of the soil / bottom of stem / AW, to top of the stem / AW ;\n2 straighten the stem (while measuring length) ;\n3 place string along stem, and measure length of string ;\n\n2(c)(i) 1.9 ; 1\n\n2(c)(ii) any one from: 1\n1 (mean stem) length was measured, in / to the nearest, cm ;\n2 many anomalies in the results / identified anomaly ;\n3 no statistical test carried out ;\n\n2(c)(iii) any one from: 1\n1 measure lengths in mm ;\n2 idea of repeat high concentration GA experiment (to check anomaly) ;\n3\n3 measure, at same time every day / for more days ;\n4 measure more seedlings / increase sample size ;\n\n2(d) (SE =) 0.067 ; 2\n(95% CI =) 1.38  0.13 ;\n© Cambridge University Press & Assessment 2024 Page 10 of 11\n\n2(e) any three from: 3\n1 highest (concentration of) GA with,red light / 680 nm\n8\nor\nlowest (concentration of) GA with, blue light / 470 nm\n1\nor\nhighest (concentration of) GA in the dark / with no light ;\n1,\n2 lower (concentration of) GA for all wavelengths of light (compared to dark)\n1\nor\nhigher (concentration of) GA for all wavelengths of light (compared to dark) ;\n8\n3 95% CI, does not overlap (for the lower concentration of GA for all wavelengths of light), so there is a significant\n1\ndifference\nor\n95% CI, does not overlap, (higher concentration of GA for all of the wavelengths of light), so there is a significant\n8\ndifference ;\n© Cambridge University Press & Assessment 2024 Page 11 of 11", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-May-June/ms/9700_s24_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-may-june/9700_s24_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s24_ms_53-p10.png", "../answer-assets/9700_s24_ms_53-p11.png" ] }, { "id": "9700-2024-on-41-q01", "question_id": "9700-2024-on-41-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "1(a)(i) A = dendrite(s) ; 3\nB = nuclei ;\nC = synaptic knob(s) ;\n\n1(a)(ii) 1 rat has, myelin sheath / Schwann cell / myelinated axon / myelinated neurone ; 2\n2 (rat has) saltatory conduction OR (rat) impulse / action potential, jumps / leaps / AW, from (one) node of Ranvier to, the\nnext / another ;\n\n1(b) any three from: 3\nsnail / Fig. 1.3\n1 greater depolarisation OR\n(membrane potential) gets more positive / has higher increase / has higher peak ;\n2 action potential, slower / takes longer / takes more time OR\nlonger time to return to resting potential ;\n3 longer (absolute / relative) refractory period ;\n4 longer hyperpolarisation ;\n5 AVP ;\n© Cambridge University Press & Assessment 2024 Page 6 of 15", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p06.png" ] }, { "id": "9700-2024-on-41-q02", "question_id": "9700-2024-on-41-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 11, "status": "available", "reason": null, "text": "2(a) any three from: 3\n1 open in, day / light ;\n2 to take in carbon dioxide for, photosynthesis / light-independent stage / Calvin cycle ;\n3 close in, night / dark ;\n4 to decrease water loss by transpiration ;\n\n2(b) any six from: 6\n1 hydrogen ions / protons / H ions / H+, leave (cell) using, energy / ATP ;\n2 low H+ (in cell) / more negative charge ;\n3 K+ / potassium ion, channel (proteins) open OR K+, move into / enter, cell (by facilitated diffusion) ;\n4 Cl – ions, move into / enter (cell) ;\n5 water potential of cell decreases ;\n6 water moves in (to cell) by osmosis ;\n7 (cells) become turgid / swell / increase in volume / expand ;\n8 (guard cell) inner wall thicker / outer wall thinner, so cells, bend / curve ;\n\n2(c) 1 (environment) light needed, to keep cycle normal / to achieve same peak % of stomata opening ; 2\n2 genes have a role as (regular), rhythm / pattern / cycle, continues, in darkness / without light ;\n© Cambridge University Press & Assessment 2024 Page 7 of 15", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p07.png" ] }, { "id": "9700-2024-on-41-q03", "question_id": "9700-2024-on-41-q03", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "3(a) 4\nevent stage\nG LR KC OP\ncatabolism ✓ ✓ ✓  ;\ncoenzyme is reduced or oxidised ✓ ✓ ✓ ✓ ;\na coenzyme forms a covalent bond with a  ✓   ;\nrespiratory intermediate\ncarbon dioxide is released  ✓ ✓  ;\n\n3(b)(i) any four from: 4\n1 (RQ =) ratio of carbon dioxide (exhaled) to oxygen (inhaled) ;\n2 air flow meter measures oxygen inhaled ;\n3 carbon dioxide sensor measures concentration of CO exhaled ;\n2\n4 carbohydrate RQ = 1 ;\n5 lipid RQ = 0.7 ;\n\n3(b)(ii) any three from: 3\n1 lipid has higher energy (value) OR\ncarbohydrate 15–17 kJ g-1 and lipid 37–40 kJ g-1 ;\n2 more, hydrogen (atoms) / C-H bonds, in lipid ;\n3 more reduced, NAD / FAD ;\n4 greater proton gradient / more protons in intermembrane space / more protons pass through ATP synth(et)ase ;\n© Cambridge University Press & Assessment 2024 Page 8 of 15", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p08.png" ] }, { "id": "9700-2024-on-41-q04", "question_id": "9700-2024-on-41-q04", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "4(a) any three from: 3\nin Venus fly traps\n1 touch two (sensory hairs) ;\n2 protons, leave hinge cells / enter hinge cell walls ;\n3 Ca2+ ions move into (hinge) cells ;\n4 water moves into (hinge) cells ;\n5 (hinge) cells, become turgid / swell / increase in volume / expand ;\n\n4(b) any two from: 2\n1 less / decreased, surface area (of leaf exposed) ;\n2 less light absorbed by, chloroplasts / thylakoid membranes / grana / pigments / chlorophyll / light harvesting\ncomplexes / photosystems ;\n3 fewer stomata, exposed / available (to air) ;\n4 less carbon dioxide, enters / absorbed ;\n\n4(c) any six from: 6\nsimilarities\n1 photoactivation of chlorophyll ;\n2 (energetic) electrons move, along / down, ETC ;\n3 chemiosmosis ;\n4 ATP produced ;\ndifferences\n5 PSI and PSII in non-cyclic and only PSI in cyclic ;\n6 photolysis / oxygen produced, in non-cyclic only ; ORA\n7 reduced NADP in non-cyclic only ; ORA\n8 electrons return to, same photosystem / PSI, in cyclic ;\n© Cambridge University Press & Assessment 2024 Page 9 of 15", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p09.png" ] }, { "id": "9700-2024-on-41-q05", "question_id": "9700-2024-on-41-q05", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "5(a) any two from: 2\n1 one / single, set of chromosomes ;\n2 have n (number of) chromosomes / half of diploid number ;\n3 chromosomes not in homologous pairs / only one of each homologous pair ;\n4 each chromosome is different in, size / shape / genes / loci ;\n\n5(b) sexual reproduction: B and D ; 3\nmitosis: two from A, B, C, D ;\nmeiosis: D ;\n\n5(c) any three from: 3\n1 to maintain, chromosome / diploid, number ;\n2 from parents to offspring / from generation to generation ;\n3 to give genetic variation in, gametes / offspring / horses ;\n4 too many / extra, sets of chromosomes cause (named) problems ;\nQuestion Answer Marks", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p10.png" ] }, { "id": "9700-2024-on-41-q06", "question_id": "9700-2024-on-41-q06", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) 1 (excess) amino acids, deaminated / have amino group removed ; 2\n2 in the liver ;\n\n6(a)(ii) any three from: 3\n1 osmoreceptors in hypothalamus (detect change / are receptors) ;\n2 effector(s): collecting duct / distal convoluted tubule / nephron ;\n3 target cells: collecting duct (cells) ;\n© Cambridge University Press & Assessment 2024 Page 10 of 15\n\n6(b) any three from: 3\n1 ultrafiltration / forms glomerular filtrate ;\n2 high, hydrostatic / blood, pressure in, glomerulus / capillaries ;\n3 so, water / (named) solutes, move (out of glomerulus / into Bowman’s capsule) ;\n4 through two of: fenestrae / fenestrations\nbasement membrane\nslit pores / filtration slits / between podocytes ;\n5 AVP ;\n\n6(c) any three from: 3\n1 high(er / est), U:P / ratio → can tolerate water shortage ;\n2 high(er / est), U:P / ratio → much water reabsorbed / small volume of urine produced ;\n3 high(er / est), U:P / ratio → can, concentrate urine / conserve water OR high(er / est), U:P / ratio → (well) adapted to dry\nenvironment ;\n4 AVP ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p10.png", "../answer-assets/9700_w24_ms_41-p11.png" ] }, { "id": "9700-2024-on-41-q07", "question_id": "9700-2024-on-41-q07", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 12, "status": "available", "reason": null, "text": "7(a)(i) any three from: 3\n1 disruptive / diversifying (selection) ;\n2 extremes / carnivores and detritus feeders, survive / are selected for and intermediates, die / are selected against ;\n3 high / intense, competition ;\n4 intermediates, outcompeted for / don’t get enough, detritus / algae, and, (fairy) shrimp / small animals ;\n5 lack of / limited, food is selection pressure ;\n6 AVP ;\n© Cambridge University Press & Assessment 2024 Page 11 of 15\n\n7(a)(ii) any three from: 3\n1 stabilising (selection) ;\n2 extremes / carnivores and detritus feeders, die / are selected against / are not selected for, and intermediates,\nsurvive / are selected for ;\n3 low / less / prevents, competition ;\n4 intermediates can eat, both types / all / a wider range, of food ;\n5 greater variety in the diet improves the growth and development of (intermediate) tadpoles ;\n\n7(a)(iii) 1\nnormal distribution curve ;\n\n7(a)(iv) any two from: 2\n1 new species form due to reproductive isolation ;\n2 caused by, ecological / behavioural, separation / isolation / differences ;\n3 in same geographical region ;\n4 AVP ;\n\n7(b) any three from: 3\n1 ref. to DNA sequence (for all / three species) ;\n2 find / count, nucleotide / base, differences / similarities ;\n3 fewer differences means, more closely related / less time since divergence / less time to common ancestor ;\n4 bioinformatics / database / software / BLAST ;\n5 S. hammondii and S. bombifrons, have the fewest genetic differences / are the most genetically similar ;\n© Cambridge University Press & Assessment 2024 Page 12 of 15", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p11.png", "../answer-assets/9700_w24_ms_41-p12.png" ] }, { "id": "9700-2024-on-41-q08", "question_id": "9700-2024-on-41-q08", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "8(a) any three from: 3\n1 make cDNA from, messenger RNA / mRNA ;\n2 using reverse transcriptase ;\n3 synthesise (gene chemically) from nucleotides / join nucleotides ;\n4 (using known) amino acid / nucleotide, sequence from database ;\n\n8(b) 3\nrole in genetic DNA ligase DNA\nengineering polymerase\njoins two sections of\nsugar phosphate ✓  ;\nbackbone in DNA\nadds a gene to a\nplasmid ✓  ;\nadds free activated\nDNA nucleotides to a  ✓ ;\npolynucleotide\n\n8(c) 1 90–98oC – DNA, denatures / strands separate ; 3\n2 50–65oC – primers, bind / base pair / anneal (to DNA) ;\n3 68–75oC – Taq / DNA, polymerase, makes, DNA / (new) strand ;\n© Cambridge University Press & Assessment 2024 Page 13 of 15", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p13.png" ] }, { "id": "9700-2024-on-41-q09", "question_id": "9700-2024-on-41-q09", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 both, eukaryotic / eukaryotes / in domain Eukarya ;\n2 example of eukaryotic feature ;\nProtoctista\n3 example of way in which they vary (must give both) ;\nFungi (max 3)\n4 cell wall of, chitin / mannan / glucan ;\n5 hyphae / mycelium ;\n6 multinucleate / syncytium / many nuclei per cell ;\n7 heterotrophic / saprotrophic / parasitic ;\n8 store glycogen ;\n9 reproduce by spores ;\n\n9(b)(i) any three from: 3\n1 measures / gives information about, air, quality / pollution ;\n2 other species may be harmed by, sulfur dioxide / acid rain / decrease in lichen (abundance / diversity) ;\n3 ref. to food web / species that feed on lichens ;\n4 AVP ;\n\n9(b)(ii) any two from: 2\n1 role in food web / eaten by other (named) species ;\n2 provide, shelter / camouflage (for insects / invertebrates) ;\n3 clean the air / remove (named) pollutants / absorb toxins ;\n4 may have medical use ;\n5 ref. to other practical use ;\n6 primary colonisers / pioneer species / soil formation ;\n7 ethical / moral / aesthetic, reason ;\n8 to conserve genetic diversity / future use for genes ;\n© Cambridge University Press & Assessment 2024 Page 14 of 15", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p14.png" ] }, { "id": "9700-2024-on-41-q10", "question_id": "9700-2024-on-41-q10", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "10(a) (melanic x melanic) 3\nAa x Aa\n(Gametes) A a and A a ;\n(Offspring) AA Aa Aa aa ;\n(melanic, melanic, melanic, typical)\n(Ratio) 3 melanic : 1 typical ;\n\n10(b) it / (melanic) allele, is dominant ; 1\n\n10(c)(i) melanic / dominant phenotype, is crossed with homozygous recessive ; 1\n\n10(c)(ii) 3\nsame locus different loci\n(A / a) (A / a and B / b)\ngenotypes of melanic AA AaBb\nmoths from cross 1 Aa Aabb\n(aA) ; aaBb ;\nproportion of test crosses 1 in 3 none / 0 ;\n(cross 2) giving 100%\nmelanic offspring\n\n10(d) (24  29) ÷ 8 ; 2\n= 87 ;\n© Cambridge University Press & Assessment 2024 Page 15 of 15", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_41-p15.png" ] }, { "id": "9700-2024-on-42-q01", "question_id": "9700-2024-on-42-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) A – podocyte ; 2\nB – (capillary) endothelial cell ;\n\n1(a)(ii) high(er), hydrostatic / blood, pressure ; Ignore ref. to water potential 2\nbasement membrane acts as a filter / only small molecules can pass through basement membrane ;\n\n1(b) 3\ncomponent of component in component in\nblood plasma in newly formed urine\nglomerulus glomerular filtrate\nglucose same not present ;\nlarge proteins not present not present ;\nurea same increased ;\n\n1(c) posterior pituitary gland – releases (more) ADH ; A secretes 2\nkidney – reabsorbs more water / urine more concentrated / lower volume of urine ;\nOR\n(more) aquaporins added to membrane of collecting duct (cells) / membrane of collecting duct (cells) more permeable to\nwater ;\n© Cambridge University Press & Assessment 2024 Page 5 of 19", "source_pages": [ 5 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p05.png" ] }, { "id": "9700-2024-on-42-q02", "question_id": "9700-2024-on-42-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "2(a) any six from: 6\n1 mutation / described ;\n2 genetic drift / described ;\n3 founder effect / group separated from main population to found a new population ;\n4 bottleneck effect / large fall in population ;\n5 natural / directional / disruptive, selection ; Ignore artificial / stabilising selection\n6 migration / gene flow / interbreeding between populations ;\n7 genetic recombination / linkage groups broken / crossing over ;\n8 AVP ; e.g. effect larger in small populations\n\n2(b) any three from: 3\n1 inbreeding / described ;\n2 produces homozygous plants / increases homozygosity ;\n3 outbreeding / described ;\n4 hybridisation / producing a hybrid ;\n5 hybrids / offspring / F1, are (all) heterozygotes / have increased heterozygosity ;\n© Cambridge University Press & Assessment 2024 Page 6 of 19", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p06.png" ] }, { "id": "9700-2024-on-42-q03", "question_id": "9700-2024-on-42-q03", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "3(a) any three from: 3\n1 manipulation of, genetic material / gene / DNA or described ;\n2 ref. to gene / allele, transfer (into, cell / organism) or described ;\n3 expression of gene ;\n4 (named) phenotype modified / (named) protein produced ;\n5 AVP ; e.g. ref. to gene editing / produce GMO\n\n3(b)(i) any three from: 3\n1 add, healthy / normal / correct / functional, gene / allele, to virus ;\n2 inject virus into eye ;\n3 gene integrated into (eye cell) genome / DNA ;\n4 gene / allele, expressed to produce functioning, protein / enzyme ;\n5 AVP ; e.g. adeno-associated virus / AAV voretigene neparvovec (drug)\n\n3(b)(ii) any one from: 1\n1 easily accessible / easy to inject ;\n2 low risk of immune response ;\n3 (eye small in size so) small amount of gene therapy treatment needed / AW ;\n© Cambridge University Press & Assessment 2024 Page 7 of 19\n\n3(c)(i) any three from: 3\n1 (overall) improvement in acuity of both eyes or (overall visual) acuity of both eyes becomes more negative ;\n2 treated eye, has more improved acuity / has more negative (visual) acuity ; ora\n3 ref. to anomalous result at month 9 / result that does not fit the pattern at month 9 ;\n4 data quote – values of one eye at two months or values of both eyes at one month ;\ntime / change in visual acuity / au\nmonths\neye not eye treated\ntreated\n0 0.00 0.00\n1 -0.12 -0.20\n2 +0.02 -0.40\n3 0.00 -0.50\n4 -0.13 -0.52\n5 -0.22 or -0.23 -0.52\n6 -0.15 -0.54\n7 -0.12 -0.50\n9 -0.15 -0.33\n10 -0.08 -0.52\n12 -0.12 -0.54\n© Cambridge University Press & Assessment 2024 Page 8 of 19\n\n3(c)(ii) any three from: 3\n1 mutated DNA is, deleted / removed / cut out or DNA replaced with normal DNA ;\nIgnore exon X is deleted as this is mRNA not DNA\nReject gene deleted / cut out\n2 specific (locations) / between exon 26 and exon 27, (in the genome) ;\n3 functional protein / CEP290, now made\nOR\ncorrect functioning of photoreceptors ;\n4 acts on person’s own DNA ;\n5 AVP ; e.g. STOP codon no longer present\nQuestion Answer Marks", "source_pages": [ 7, 8, 9 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p07.png", "../answer-assets/9700_w24_ms_42-p08.png", "../answer-assets/9700_w24_ms_42-p09.png" ] }, { "id": "9700-2024-on-42-q04", "question_id": "9700-2024-on-42-q04", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 6, "status": "available", "reason": null, "text": "4(a) parental genotype Rr x Rr 3\nAND\ngametes R r R r ;\noffspring genotype RR Rr (Rr) rr ;\nred red red yellow ;\n© Cambridge University Press & Assessment 2024 Page 9 of 19\n\n4(b) 1 ratio=9:3:3:1 ; 3\nany two from:\n2 independent / random, assortment ;\n3 of, homologous chromosomes / bivalents / sister chromatids ;\n4 stage of meiosis ; e.g. metaphase 1 or metaphase 11\nIgnore ref. to crossing over / recombinants\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p09.png", "../answer-assets/9700_w24_ms_42-p10.png" ] }, { "id": "9700-2024-on-42-q05", "question_id": "9700-2024-on-42-q05", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 12, "status": "available", "reason": null, "text": "5(a) 4\nstatement discontinuous continuous\nvariation variation\noften involves one gene only \nenvironmental factors may affect \ngene expression\nthere is an additive effect of genes \nthat contributes to the phenotype\nthere are distinct differences \nbetween the various forms of a ;;;;\ncharacteristic\n\n5(b)(i) ref. to spread of results about the mean ; 1\n© Cambridge University Press & Assessment 2024 Page 10 of 19\n\n5(b)(ii) t = 4.255 ;;; 3\ngive 2 marks:\nif answer is 4.25 or 4.26\nif answer is more than 4 significant figures e.g. 4.255439871\nif answer is incorrectly rounded to 4 significant figures e.g. 4.256\nif answer incorrect then max 2 for working\nnumerator = 4.2\ndenominator = 0.986972\necf - if no working mark given then allow one mark for 12.02 as the answer\n\n5(b)(iii) 1 there is a higher (mean) concentration of serum 25-OHD in summer ; ora 3\nany two from:\n2 value of t / 4.255 > critical value / 3.773 ;\n3 there is a significant difference between the two means ;\n4 any difference is not due to chance / difference due to chance less than 0.0001% ;\necf from incorrect answer to 5bii\n\n5(b)(iv) genetic AND environmental 1\nOR\nan example of a genetic cause AND an example of an environmental cause ;\n© Cambridge University Press & Assessment 2024 Page 11 of 19", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p10.png", "../answer-assets/9700_w24_ms_42-p11.png" ] }, { "id": "9700-2024-on-42-q06", "question_id": "9700-2024-on-42-q06", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "6(a)(i) redox ; 1\n\n6(a)(ii) blue to colourless ; 1\n\n6(b)(i) any two from: 2\n1 volume / mass / concentration, of yeast suspension ;\n2 volume / mass / concentration, of glucose (solution) ;\n3 volume / concentration, of DCPIP ;\n4 AVP ; e.g. time when DCPIP is added / pH\n\n6(b)(ii) any three from: 3\n1 the less time taken (for DCPIP) to change colour the higher the rate of respiration ; ora\nrate increases up to 40 °C\n2 due to increase in, kinetic energy / KE ;\n3 due to more enzyme-substrate complexes formed or due to more (successful / effective) collisions between enzymes\nand substrates or more enzyme catalysed reactions ;\nrate decreases after 40 °C\n4 due to denaturation of (named respiration) enzyme ;\n5 further detail ; e.g. active site shape change / optimum temperature 40 °C\n© Cambridge University Press & Assessment 2024 Page 12 of 19", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p12.png" ] }, { "id": "9700-2024-on-42-q07", "question_id": "9700-2024-on-42-q07", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "7(a) 1 calculate R value(s) ; 3\nf\n2 (R = ) distance moved by pigment (from baseline)\nf\ndistance moved by solvent (from baseline) ;\n3 compare with, known / standard / table, values ;\n\n7(b) any three from: 3\n1 absorb light wavelengths not absorbed by, reaction centre / primary pigment / chlorophyll a ; A harvest\n2 so extend the range of wavelengths absorbed ;\n3 pass energy to, reaction centre / primary pigment / chlorophyll a ;\n4 ref. to accessory pigments ;\n© Cambridge University Press & Assessment 2024 Page 13 of 19\n\n7(c) any seven from: 7\n1 carbon dioxide, reacts / combines, with, ribulose bisphosphate / RuBP ;\n2 (catalysed by) rubisco ;\n3 ref. to carbon (dioxide) fixation ;\n4 unstable 6C compound ;\n5 forms 2 (molecules of) glycerate 3-phosphate / GP ;\n6 glycerate 3-phosphate / GP, reduced to, triose phosphate / TP ;\n7 by reduced NADP and ATP ;\n8 triose phosphate / TP, used to regenerate RuBP ;\n9 glycerate 3-phosphate / GP, forms amino acids ;\n10 (some) TP forms, (named) hexoses / sucrose / maltose / starch / cellulose / glycerol / lipids / amino acids ;\n11 ref. to Calvin cycle ;\n© Cambridge University Press & Assessment 2024 Page 14 of 19", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p13.png", "../answer-assets/9700_w24_ms_42-p14.png" ] }, { "id": "9700-2024-on-42-q08", "question_id": "9700-2024-on-42-q08", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 11, "status": "available", "reason": null, "text": "8(a)(i) X – Schwann (cell) ; Ignore myelin sheath (as not a cell) 2\nY – cell body ; A cytoplasm\n\n8(a)(ii) intermediate neurone ; A relay neurone / sensory neurone 1\n\n8(b) 4\ncorrect order letter of stage\n1 C\n2 F\n3 A\n4 E\n5 J\n6 I\n7 G\n8 B\n9 H\n10 D\nC F A E all above J ;\nC F A E in correct order ;\nI G B H between J and D ;\nI G B H in correct order ;\n© Cambridge University Press & Assessment 2024 Page 15 of 19\n\n8(c) any four from: 4\nallow ‘no’ for ‘less’ or ‘fewer’\n1 less / fewer, Ca2+ enter (pre)synaptic knob ;\n2 less / fewer, vesicles, move to / fuse with, presynaptic membrane ;\n3 less, ACh released / exocytosis of ACh ;\n4 less binding of ACh to receptors (on sarcolemma) ;\n5 fewer, Na+ channels open / Na+ enter (muscle fibre) ;\n6 less depolarisation of sarcolemma / threshold potential not reached / fewer action potentials generated ;\nIgnore postsynaptic membrane\n7 less Ca2+ released from SR / less binding of Ca2+ to troponin / fewer sites exposed / fewer cross bridges ;\nQuestion Answer Marks", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p15.png", "../answer-assets/9700_w24_ms_42-p16.png" ] }, { "id": "9700-2024-on-42-q09", "question_id": "9700-2024-on-42-q09", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 10, "status": "available", "reason": null, "text": "9(a) any three from: 3\n1 loss of habitat / example ;\n2 hunted / poaching / increased predation ;\n3 climate change / example ;\n4 competition for, food / resources / example ;\n5 new disease ;\n6 illegal pet / fur, trade ;\n© Cambridge University Press & Assessment 2024 Page 16 of 19\n\n9(b) 1 large / steep, increase from 1980 to 1990 ; 3\n2 plateau / remains constant or slight changes / fluctuates ;\n3 data quote (two numbers and two years) ;\nyear number of lemurs born\n1970 5\n1980 32 / 33\n1990 175\n2000 175\n2010 184 / 185\n2020 170\n\n9(c)(i) any three from: 3\n1 stress (in captivity) ;\n2 reproductive cycle disrupted ;\n3 may reject mate / refuse to breed / do not have correct (courtship) behaviour ;\n4 lack of suitable mates ;\n5 enclosure too small / not natural environment ;\n6 expensive ;\n7 AVP ; e.g. inbreeding\n© Cambridge University Press & Assessment 2024 Page 17 of 19\n\n9(c)(ii) increase / maintain, genetic diversity / heterozygosity / hybrid vigour / gene pool 1\nOR\nreduce, inbreeding depression / homozygosity ;\nQuestion Answer Marks", "source_pages": [ 16, 17, 18 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p16.png", "../answer-assets/9700_w24_ms_42-p17.png", "../answer-assets/9700_w24_ms_42-p18.png" ] }, { "id": "9700-2024-on-42-q10", "question_id": "9700-2024-on-42-q10", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 10, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 changes in factor / stimulus, detected by receptor ;\n2 ref. to CNS / brain / coordinator ;\n3 impulses / (named) hormone, sent to, (named) effector / muscle / gland ;\n4 (named) effector / muscle / gland, carries out response ;\n5 factor returns to, set point / norm ;\n6 negative feedback ;\n7 AVP ; e.g. cell signalling\n© Cambridge University Press & Assessment 2024 Page 18 of 19\n\n10(b) any three from: 3\ncell signalling carries on\n1 / 2 two details ;; e.g. glucagon binds to receptors / adenylyl cyclase stimulated / G protein activated / cAMP\nformed / protein kinase A activated / enzyme cascade\n3 no / less, (functioning) glycogen phosphorylase (produced)\nOR\nnon-functioning glycogen phosphorylase (produced)\nOR\nno / less, glycogen phosphorylase activated ;\n4 change in, tertiary structure / active site ;\n5 (so) less / no, glycogen converted to glucose / glycogenolysis ;\n\n10(c) any three from: 3\n1 no / less, (functioning) glycogen synthase (produced) or non-functioning glycogen synthase (produced) or no / less,\nglycogen synthase activated ;\n2 high / increase in, blood glucose concentration (following this meal) ;\n3 (so) glucose (excreted) in urine ;\n4 more lipid synthesis ;\n5 inhibits release of glucagon ;\n6 AVP ; e.g. affects blood water potential / dehydration / thirst / tiredness / coma / affects blood pressure\n© Cambridge University Press & Assessment 2024 Page 19 of 19", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_42-p18.png", "../answer-assets/9700_w24_ms_42-p19.png" ] }, { "id": "9700-2024-on-43-q01", "question_id": "9700-2024-on-43-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "1(a)(i) A = dendrite(s) ; 3\nB = nuclei ;\nC = synaptic knob(s) ;\n\n1(a)(ii) 1 rat has, myelin sheath / Schwann cell / myelinated axon / myelinated neurone ; 2\n2 (rat has) saltatory conduction OR (rat) impulse / action potential, jumps / leaps / AW, from (one) node of Ranvier to, the\nnext / another ;\n\n1(b) any three from: 3\nsnail / Fig. 1.3\n1 greater depolarisation OR\n(membrane potential) gets more positive / has higher increase / has higher peak ;\n2 action potential, slower / takes longer / takes more time OR\nlonger time to return to resting potential ;\n3 longer (absolute / relative) refractory period ;\n4 longer hyperpolarisation ;\n5 AVP ;\n© Cambridge University Press & Assessment 2024 Page 6 of 15", "source_pages": [ 6 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p06.png" ] }, { "id": "9700-2024-on-43-q02", "question_id": "9700-2024-on-43-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 11, "status": "available", "reason": null, "text": "2(a) any three from: 3\n1 open in, day / light ;\n2 to take in carbon dioxide for, photosynthesis / light-independent stage / Calvin cycle ;\n3 close in, night / dark ;\n4 to decrease water loss by transpiration ;\n\n2(b) any six from: 6\n1 hydrogen ions / protons / H ions / H+, leave (cell) using, energy / ATP ;\n2 low H+ (in cell) / more negative charge ;\n3 K+ / potassium ion, channel (proteins) open OR K+, move into / enter, cell (by facilitated diffusion) ;\n4 Cl – ions, move into / enter (cell) ;\n5 water potential of cell decreases ;\n6 water moves in (to cell) by osmosis ;\n7 (cells) become turgid / swell / increase in volume / expand ;\n8 (guard cell) inner wall thicker / outer wall thinner, so cells, bend / curve ;\n\n2(c) 1 (environment) light needed, to keep cycle normal / to achieve same peak % of stomata opening ; 2\n2 genes have a role as (regular), rhythm / pattern / cycle, continues, in darkness / without light ;\n© Cambridge University Press & Assessment 2024 Page 7 of 15", "source_pages": [ 7 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p07.png" ] }, { "id": "9700-2024-on-43-q03", "question_id": "9700-2024-on-43-q03", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "3(a) 4\nevent stage\nG LR KC OP\ncatabolism ✓ ✓ ✓  ;\ncoenzyme is reduced or oxidised ✓ ✓ ✓ ✓ ;\na coenzyme forms a covalent bond with a  ✓   ;\nrespiratory intermediate\ncarbon dioxide is released  ✓ ✓  ;\n\n3(b)(i) any four from: 4\n1 (RQ =) ratio of carbon dioxide (exhaled) to oxygen (inhaled) ;\n2 air flow meter measures oxygen inhaled ;\n3 carbon dioxide sensor measures concentration of CO exhaled ;\n2\n4 carbohydrate RQ = 1 ;\n5 lipid RQ = 0.7 ;\n\n3(b)(ii) any three from: 3\n1 lipid has higher energy (value) OR\ncarbohydrate 15–17 kJ g-1 and lipid 37–40 kJ g-1 ;\n2 more, hydrogen (atoms) / C-H bonds, in lipid ;\n3 more reduced, NAD / FAD ;\n4 greater proton gradient / more protons in intermembrane space / more protons pass through ATP synth(et)ase ;\n© Cambridge University Press & Assessment 2024 Page 8 of 15", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p08.png" ] }, { "id": "9700-2024-on-43-q04", "question_id": "9700-2024-on-43-q04", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "4(a) any three from: 3\nin Venus fly traps\n1 touch two (sensory hairs) ;\n2 protons, leave hinge cells / enter hinge cell walls ;\n3 Ca2+ ions move into (hinge) cells ;\n4 water moves into (hinge) cells ;\n5 (hinge) cells, become turgid / swell / increase in volume / expand ;\n\n4(b) any two from: 2\n1 less / decreased, surface area (of leaf exposed) ;\n2 less light absorbed by, chloroplasts / thylakoid membranes / grana / pigments / chlorophyll / light harvesting\ncomplexes / photosystems ;\n3 fewer stomata, exposed / available (to air) ;\n4 less carbon dioxide, enters / absorbed ;\n\n4(c) any six from: 6\nsimilarities\n1 photoactivation of chlorophyll ;\n2 (energetic) electrons move, along / down, ETC ;\n3 chemiosmosis ;\n4 ATP produced ;\ndifferences\n5 PSI and PSII in non-cyclic and only PSI in cyclic ;\n6 photolysis / oxygen produced, in non-cyclic only ; ORA\n7 reduced NADP in non-cyclic only ; ORA\n8 electrons return to, same photosystem / PSI, in cyclic ;\n© Cambridge University Press & Assessment 2024 Page 9 of 15", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p09.png" ] }, { "id": "9700-2024-on-43-q05", "question_id": "9700-2024-on-43-q05", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "5(a) any two from: 2\n1 one / single, set of chromosomes ;\n2 have n (number of) chromosomes / half of diploid number ;\n3 chromosomes not in homologous pairs / only one of each homologous pair ;\n4 each chromosome is different in, size / shape / genes / loci ;\n\n5(b) sexual reproduction: B and D ; 3\nmitosis: two from A, B, C, D ;\nmeiosis: D ;\n\n5(c) any three from: 3\n1 to maintain, chromosome / diploid, number ;\n2 from parents to offspring / from generation to generation ;\n3 to give genetic variation in, gametes / offspring / horses ;\n4 too many / extra, sets of chromosomes cause (named) problems ;\nQuestion Answer Marks", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p10.png" ] }, { "id": "9700-2024-on-43-q06", "question_id": "9700-2024-on-43-q06", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) 1 (excess) amino acids, deaminated / have amino group removed ; 2\n2 in the liver ;\n\n6(a)(ii) any three from: 3\n1 osmoreceptors in hypothalamus (detect change / are receptors) ;\n2 effector(s): collecting duct / distal convoluted tubule / nephron ;\n3 target cells: collecting duct (cells) ;\n© Cambridge University Press & Assessment 2024 Page 10 of 15\n\n6(b) any three from: 3\n1 ultrafiltration / forms glomerular filtrate ;\n2 high, hydrostatic / blood, pressure in, glomerulus / capillaries ;\n3 so, water / (named) solutes, move (out of glomerulus / into Bowman’s capsule) ;\n4 through two of: fenestrae / fenestrations\nbasement membrane\nslit pores / filtration slits / between podocytes ;\n5 AVP ;\n\n6(c) any three from: 3\n1 high(er / est), U:P / ratio → can tolerate water shortage ;\n2 high(er / est), U:P / ratio → much water reabsorbed / small volume of urine produced ;\n3 high(er / est), U:P / ratio → can, concentrate urine / conserve water OR high(er / est), U:P / ratio → (well) adapted to dry\nenvironment ;\n4 AVP ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p10.png", "../answer-assets/9700_w24_ms_43-p11.png" ] }, { "id": "9700-2024-on-43-q07", "question_id": "9700-2024-on-43-q07", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 12, "status": "available", "reason": null, "text": "7(a)(i) any three from: 3\n1 disruptive / diversifying (selection) ;\n2 extremes / carnivores and detritus feeders, survive / are selected for and intermediates, die / are selected against ;\n3 high / intense, competition ;\n4 intermediates, outcompeted for / don’t get enough, detritus / algae, and, (fairy) shrimp / small animals ;\n5 lack of / limited, food is selection pressure ;\n6 AVP ;\n© Cambridge University Press & Assessment 2024 Page 11 of 15\n\n7(a)(ii) any three from: 3\n1 stabilising (selection) ;\n2 extremes / carnivores and detritus feeders, die / are selected against / are not selected for, and intermediates,\nsurvive / are selected for ;\n3 low / less / prevents, competition ;\n4 intermediates can eat, both types / all / a wider range, of food ;\n5 greater variety in the diet improves the growth and development of (intermediate) tadpoles ;\n\n7(a)(iii) 1\nnormal distribution curve ;\n\n7(a)(iv) any two from: 2\n1 new species form due to reproductive isolation ;\n2 caused by, ecological / behavioural, separation / isolation / differences ;\n3 in same geographical region ;\n4 AVP ;\n\n7(b) any three from: 3\n1 ref. to DNA sequence (for all / three species) ;\n2 find / count, nucleotide / base, differences / similarities ;\n3 fewer differences means, more closely related / less time since divergence / less time to common ancestor ;\n4 bioinformatics / database / software / BLAST ;\n5 S. hammondii and S. bombifrons, have the fewest genetic differences / are the most genetically similar ;\n© Cambridge University Press & Assessment 2024 Page 12 of 15", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p11.png", "../answer-assets/9700_w24_ms_43-p12.png" ] }, { "id": "9700-2024-on-43-q08", "question_id": "9700-2024-on-43-q08", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "8(a) any three from: 3\n1 make cDNA from, messenger RNA / mRNA ;\n2 using reverse transcriptase ;\n3 synthesise (gene chemically) from nucleotides / join nucleotides ;\n4 (using known) amino acid / nucleotide, sequence from database ;\n\n8(b) 3\nrole in genetic DNA ligase DNA\nengineering polymerase\njoins two sections of\nsugar phosphate ✓  ;\nbackbone in DNA\nadds a gene to a\nplasmid ✓  ;\nadds free activated\nDNA nucleotides to a  ✓ ;\npolynucleotide\n\n8(c) 1 90–98oC – DNA, denatures / strands separate ; 3\n2 50–65oC – primers, bind / base pair / anneal (to DNA) ;\n3 68–75oC – Taq / DNA, polymerase, makes, DNA / (new) strand ;\n© Cambridge University Press & Assessment 2024 Page 13 of 15", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p13.png" ] }, { "id": "9700-2024-on-43-q09", "question_id": "9700-2024-on-43-q09", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 both, eukaryotic / eukaryotes / in domain Eukarya ;\n2 example of eukaryotic feature ;\nProtoctista\n3 example of way in which they vary (must give both) ;\nFungi (max 3)\n4 cell wall of, chitin / mannan / glucan ;\n5 hyphae / mycelium ;\n6 multinucleate / syncytium / many nuclei per cell ;\n7 heterotrophic / saprotrophic / parasitic ;\n8 store glycogen ;\n9 reproduce by spores ;\n\n9(b)(i) any three from: 3\n1 measures / gives information about, air, quality / pollution ;\n2 other species may be harmed by, sulfur dioxide / acid rain / decrease in lichen (abundance / diversity) ;\n3 ref. to food web / species that feed on lichens ;\n4 AVP ;\n\n9(b)(ii) any two from: 2\n1 role in food web / eaten by other (named) species ;\n2 provide, shelter / camouflage (for insects / invertebrates) ;\n3 clean the air / remove (named) pollutants / absorb toxins ;\n4 may have medical use ;\n5 ref. to other practical use ;\n6 primary colonisers / pioneer species / soil formation ;\n7 ethical / moral / aesthetic, reason ;\n8 to conserve genetic diversity / future use for genes ;\n© Cambridge University Press & Assessment 2024 Page 14 of 15", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p14.png" ] }, { "id": "9700-2024-on-43-q10", "question_id": "9700-2024-on-43-q10", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "10(a) (melanic x melanic) 3\nAa x Aa\n(Gametes) A a and A a ;\n(Offspring) AA Aa Aa aa ;\n(melanic, melanic, melanic, typical)\n(Ratio) 3 melanic : 1 typical ;\n\n10(b) it / (melanic) allele, is dominant ; 1\n\n10(c)(i) melanic / dominant phenotype, is crossed with homozygous recessive ; 1\n\n10(c)(ii) 3\nsame locus different loci\n(A / a) (A / a and B / b)\ngenotypes of melanic AA AaBb\nmoths from cross 1 Aa Aabb\n(aA) ; aaBb ;\nproportion of test crosses 1 in 3 none / 0 ;\n(cross 2) giving 100%\nmelanic offspring\n\n10(d) (24  29) ÷ 8 ; 2\n= 87 ;\n© Cambridge University Press & Assessment 2024 Page 15 of 15", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_43-p15.png" ] }, { "id": "9700-2024-on-51-q01", "question_id": "9700-2024-on-51-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 21, "status": "available", "reason": null, "text": "1(a)(i) 0.40 ; 1\n\n1(a)(ii) fucoxanthin ; 2\ndiadinoxanthin ;\n\n1(b) blue light: 3\n1 S. costatum (will have), greater / faster / AW , (rate of photosynthesis than R. salina) ; ora\ngreen light:\n2 S. costatum (will have), slightly / AW, greater / faster / AW , (rate of photosynthesis than R. salina) ; ora\nred light:\n3 S. costatum (will have), the same / similar / AW, (rate of photosynthesis as R. salina) ;\n\n1(c)(i) any one from: 1\n1 idea that absorbance measured (with colorimeter) / colour of indicator solution, is not affected by algae ;\n2 indicator solution can be separated from algal balls ;\n3 (more accurate) standardisation of, mass / volume / AW, of algae ;\n\n1(c)(ii) independent variables: 3\nspecies / type, (of algal beads) ;\nwavelength / colour, of light ;\ndependent variable:\nabsorbance / pH (of solution) ;\n© Cambridge University Press & Assessment 2024 Page 6 of 10\n\n1(c)(iii) any eight from: 8\n1 method for use of filters (to give blue, green, red coloured light) ;\n2 use, same / stated, number / mass / volume, of algal beads (in each bottle) ;\n3 place light source the, same / stated, distance (from algal beads) ;\n4 carry out experiment in a darkened room ;\n5 use, same / stated, volume / concentration, of indicator (in each bottle) ;\n6 (use of a control bottle) replace the algal beads with, glass / plastic / AW, beads ;\n7 use, red / pH 8.4, hydrogencarbonate indicator solution (at start) ;\n8 detail of method to take sample (of indicator solution) from bottle ;\n9 use a, same / stated, coloured, filter / light, in the colorimeter ;\n10 method to calibrate colorimeter ;\n11 ref. to, suitable time to leave algal beads and indicator solution (before measuring absorbance) ;\n12 for each colour (filter) and species, measure / record / AW, absorbance, at same / stated, time(s) ;\n13 use at least three measurements for each colour (filter) and species, and calculate a mean ;\n© Cambridge University Press & Assessment 2024 Page 7 of 10\n\n1(c)(iv) hazard and risk and precaution ; 1\nhazard risk precaution\nalgae / beads irritant / allergy gloves / mask / goggles / PPE\nhydrogencarbonate irritant / allergy gloves / mask / goggles / PPE\nindicator (solution)\nheat from light source burns do not touch bulb / turn off lamp before\nhandling\n\n1(d)(i) any one from: 1\n1 comparing the means of two (sets of data) ;\n2 continuous data (collected) ;\n3 (data are from populations that are) normally distributed ;\n4 standard deviations are approximately the same ;\n\n1(d)(ii) there is no difference, in the pH of samples (taken from the small bottles / of indicator solution), between R. salina and S. 1\ncostatum ;\n© Cambridge University Press & Assessment 2024 Page 8 of 10", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_51-p06.png", "../answer-assets/9700_w24_ms_51-p07.png", "../answer-assets/9700_w24_ms_51-p08.png" ] }, { "id": "9700-2024-on-51-q02", "question_id": "9700-2024-on-51-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "2(a) 1 peat bog A has a higher number of species and a higher Shannon index (than peat bog B) ; ora 2\nexamples of suitable wording for mp1:\nnumber of species Shannon index\npeat bog A has a higher number of species ora peat bog A has a higher Shannon index ora\npeat bog A has 12 species, peat bog B has only 8 idea that number of species / species richness, is\nspecies more important for Shannon index\nno (individuals of) species T, U, W, V in peat bog B\n2 peat bog B has a smaller range of species abundance and a higher Simpson’s index (than peat bog A) ; ora\nexamples of suitable wording for mp2:\nrelative species abundance Simpson’s index\npeat bog B has a smaller range of species peat bog B has a higher Simpson’s index ora\nabundance ora\nidea that (range of) species abundance / species\npeat bog B has a higher (total) number of individuals evenness / total number of individuals, is more\nora important for Simpson’s index\npeat bog B has 135 (total) number of individuals,\npeat bog A has only 99\nif mp1 and mp2 not awarded, then award 1 mark for:\npeat bog A has a higher number of species and peat bog B has a smaller range of species abundance ; ora\n© Cambridge University Press & Assessment 2024 Page 9 of 10\n\n2(a) examples of suitable wording:\nnumber of species relative species abundance\npeat bog A has a higher number of species ora peat bog B has a smaller range of species\nabundance ora\npeat bog A has 12 species, peat bog B has only 8\nspecies peat bog B has a higher (total) number of individuals\nora\nno (individuals of) species T, U, W, V in peat bog B\npeat bog B has 135 (total) number of individuals,\npeat bog A has only 99\n\n2(b)(i) any three from: 3\n1 sample at different times of the year (not only over one month) ;\n2 sample at, night / different times of day (not only between 13:00 and 16:00) ;\n3 sample at sites other than along the path ;\n4 use of (another) named technique to sample invertebrates ;\n5 use an expert / (identification) app / guidebook (instead of an identification key) ;\n\n2(b)(ii) 1 (for Tipula limbata) n / N = 0.083 and (n / N)2 = 0.007 ; 3\n2  = 0.270 ;\n3 D = 0.730 ;\n\n2(b)(iii) peat bog A has (slightly) higher (biodiversity than peat bog B) ; ora 1\n© Cambridge University Press & Assessment 2024 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_51-p09.png", "../answer-assets/9700_w24_ms_51-p10.png" ] }, { "id": "9700-2024-on-52-q01", "question_id": "9700-2024-on-52-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 replace chloroplast (suspension) with, water / boiled chloroplast (suspension) ;\n2 replace DCPIP with, water ;\n3 keep (chloroplast suspension with DCPIP) in the dark ;\n\n1(b)(i) 2\npercentage\ntime taken for rate of light-dependent\nconcentration of\nDCPIP to stage of photosynthesis\nchloroplast\ndecolourise / s / s–1\nsuspension\n10 351 2.8\n20 59 16.9\n30 21 47.6\n40 10 100.0\n50 5 200.0\nrates calculated correctly ;\n(correct) rates correctly rounded to one decimal place ;\n\n1(b)(ii) 1 axes correctly orientated with labels and rate unit and appropriate scales ; 3\n2 points plotted accurately (± ½ small square) ;\n3 suitable line drawn ;\n© Cambridge University Press & Assessment 2024 Page 6 of 10\n\n1(c) any two from: 2\n(Did work in 10% sucrose solution because)\n1 (sucrose solution) has, same / similar, water potential as in the chloroplast ;\n2 water will not enter (chloroplast), by osmosis / as there is no water potential gradient / ora ;\n3 chloroplasts will not burst / ora ;\n\n1(d) 1 one, stated, concentration of chloroplast suspension ; 6\nany five from:\n2 minimum of five, stated, temperatures within the range 10 to 60 °C ;\n3 method of maintaining a constant temperature ;\n4 allowing chloroplast suspensions to reach set temperatures (before exposing to light) ;\n5 swirl chloroplast suspension (before exposing to light) ;\n6 method for ensuring same light intensity ;\n7 carry out experiment in dark room ;\n8 colour of sample to match chloroplast suspension (alone) / green colour standard ;\n9 correct ref. to repeats and mean ;\n© Cambridge University Press & Assessment 2024 Page 7 of 10", "source_pages": [ 6, 7 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_52-p06.png", "../answer-assets/9700_w24_ms_52-p07.png" ] }, { "id": "9700-2024-on-52-q02", "question_id": "9700-2024-on-52-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "2(a)(i) 3\n1 description of random / systematic, sampling ;\n2 use of, quadrats / (sweep) nets / (light) trap / pooter ;\n3 Count the number of each phenotypes ;\nOR\nmax. 2 marks if Mark-Release-Recapture method\n4 capture ladybirds and count / find number / record, number of each phenotypes and mark and release them ;\n5 suitable marking so not harmful / too obvious / not removed\n6 capture second sample and count / find number / record, number of each phenotypes and count / find number / record\nnumber, of marked each phenotypes ;\n\n2(a)(ii) 2\nany two from:\n1 ref. to data for spring 1929 and spring 1932 ;\n2 sample size(s) ;\n3 multiple sampling sites (in same area of Germany) ;\n4 carry out statistical analysis ;\nSampling took place with:\n5 the same location(s) / habitat(s) / sampling site(s) / AW ;\n6 the same time of day ;\n7 the same duration (of sampling) ;\n\n2(b)(i) Line for melanic phenotype is steeper (than non-melanic phenotype) ; 1\n© Cambridge University Press & Assessment 2024 Page 8 of 10\n\n2(b)(ii) 1 award if both graphs have been used ; 3\nany two from:\n2 all ladybirds have the same starting temperature ;\n3 all ladybirds warm up when lamp is on ;\n4 all ladybirds return to, original / starting, temperature ;\n5 melanic reaches higher temperature / ora ;\n6 melanic cool down faster / ora ;\n7 females warm up quicker / ora ;\n8 females reach higher temperature / ora ;\n9 females take longer to cool down / ora ;\n10 heavier warm up quicker / ora ;\n11 heavier ladybirds reach higher temperature / ora ;\n12 heavier ladybirds take longer to cool down / ora ;\n13 the temperature plateaus for all except non-melanic females ;\n\n2(c) 1 Pearson’s (linear correlation) / Spearman’s (rank correlation) ; 3\nany two from:\nPearson’s\n2 data (for temperature and mass) is, paired / linked ;\n3 data is continuous ;\n4 scatter diagram, suggests a linear, relationship / correlation / association ;\n5 there are at least 5 (paired) observations ;\nOR\nSpearman’s\n6 data (for temperature and mass) is, paired / linked ;\n7 the data is ordinal / interval ;\n8 scatter diagram, suggests an increasing, relationship / correlation / association ;\n9 there are more than 5 (paired) observations ;\n© Cambridge University Press & Assessment 2024 Page 9 of 10\n\n2(d) 1 cross melanic with non-melanic ; 3\n2 homozygous (dominant) melanic parent(s) will only have melanic offspring\nand\nheterozygous (melanic) parent(s) will have both phenotypes in offspring ;\nDetails about breeding experiment – max 1\n3 many breeding pairs ;\n4 each breeding pair kept separate from other pairs\nor\nseparate offspring from parents ;\n5 count, the different phenotypes of offspring ;\n© Cambridge University Press & Assessment 2024 Page 10 of 10", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_52-p08.png", "../answer-assets/9700_w24_ms_52-p09.png", "../answer-assets/9700_w24_ms_52-p10.png" ] }, { "id": "9700-2024-on-53-q01", "question_id": "9700-2024-on-53-q01", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 21, "status": "available", "reason": null, "text": "1(a)(i) 0.40 ; 1\n\n1(a)(ii) fucoxanthin ; 2\ndiadinoxanthin ;\n\n1(b) blue light: 3\n1 S. costatum (will have), greater / faster / AW , (rate of photosynthesis than R. salina) ; ora\ngreen light:\n2 S. costatum (will have), slightly / AW, greater / faster / AW , (rate of photosynthesis than R. salina) ; ora\nred light:\n3 S. costatum (will have), the same / similar / AW, (rate of photosynthesis as R. salina) ;\n\n1(c)(i) any one from: 1\n1 idea that absorbance measured (with colorimeter) / colour of indicator solution, is not affected by algae ;\n2 indicator solution can be separated from algal balls ;\n3 (more accurate) standardisation of, mass / volume / AW, of algae ;\n\n1(c)(ii) independent variables: 3\nspecies / type, (of algal beads) ;\nwavelength / colour, of light ;\ndependent variable:\nabsorbance / pH (of solution) ;\n© Cambridge University Press & Assessment 2024 Page 6 of 10\n\n1(c)(iii) any eight from: 8\n1 method for use of filters (to give blue, green, red coloured light) ;\n2 use, same / stated, number / mass / volume, of algal beads (in each bottle) ;\n3 place light source the, same / stated, distance (from algal beads) ;\n4 carry out experiment in a darkened room ;\n5 use, same / stated, volume / concentration, of indicator (in each bottle) ;\n6 (use of a control bottle) replace the algal beads with, glass / plastic / AW, beads ;\n7 use, red / pH 8.4, hydrogencarbonate indicator solution (at start) ;\n8 detail of method to take sample (of indicator solution) from bottle ;\n9 use a, same / stated, coloured, filter / light, in the colorimeter ;\n10 method to calibrate colorimeter ;\n11 ref. to, suitable time to leave algal beads and indicator solution (before measuring absorbance) ;\n12 for each colour (filter) and species, measure / record / AW, absorbance, at same / stated, time(s) ;\n13 use at least three measurements for each colour (filter) and species, and calculate a mean ;\n© Cambridge University Press & Assessment 2024 Page 7 of 10\n\n1(c)(iv) hazard and risk and precaution ; 1\nhazard risk precaution\nalgae / beads irritant / allergy gloves / mask / goggles / PPE\nhydrogencarbonate irritant / allergy gloves / mask / goggles / PPE\nindicator (solution)\nheat from light source burns do not touch bulb / turn off lamp before\nhandling\n\n1(d)(i) any one from: 1\n1 comparing the means of two (sets of data) ;\n2 continuous data (collected) ;\n3 (data are from populations that are) normally distributed ;\n4 standard deviations are approximately the same ;\n\n1(d)(ii) there is no difference, in the pH of samples (taken from the small bottles / of indicator solution), between R. salina and S. 1\ncostatum ;\n© Cambridge University Press & Assessment 2024 Page 8 of 10", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_53-p06.png", "../answer-assets/9700_w24_ms_53-p07.png", "../answer-assets/9700_w24_ms_53-p08.png" ] }, { "id": "9700-2024-on-53-q02", "question_id": "9700-2024-on-53-q02", "subject": "9700", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "2(a) 1 peat bog A has a higher number of species and a higher Shannon index (than peat bog B) ; ora 2\nexamples of suitable wording for mp1:\nnumber of species Shannon index\npeat bog A has a higher number of species ora peat bog A has a higher Shannon index ora\npeat bog A has 12 species, peat bog B has only 8 idea that number of species / species richness, is\nspecies more important for Shannon index\nno (individuals of) species T, U, W, V in peat bog B\n2 peat bog B has a smaller range of species abundance and a higher Simpson’s index (than peat bog A) ; ora\nexamples of suitable wording for mp2:\nrelative species abundance Simpson’s index\npeat bog B has a smaller range of species peat bog B has a higher Simpson’s index ora\nabundance ora\nidea that (range of) species abundance / species\npeat bog B has a higher (total) number of individuals evenness / total number of individuals, is more\nora important for Simpson’s index\npeat bog B has 135 (total) number of individuals,\npeat bog A has only 99\nif mp1 and mp2 not awarded, then award 1 mark for:\npeat bog A has a higher number of species and peat bog B has a smaller range of species abundance ; ora\n© Cambridge University Press & Assessment 2024 Page 9 of 10\n\n2(a) examples of suitable wording:\nnumber of species relative species abundance\npeat bog A has a higher number of species ora peat bog B has a smaller range of species\nabundance ora\npeat bog A has 12 species, peat bog B has only 8\nspecies peat bog B has a higher (total) number of individuals\nora\nno (individuals of) species T, U, W, V in peat bog B\npeat bog B has 135 (total) number of individuals,\npeat bog A has only 99\n\n2(b)(i) any three from: 3\n1 sample at different times of the year (not only over one month) ;\n2 sample at, night / different times of day (not only between 13:00 and 16:00) ;\n3 sample at sites other than along the path ;\n4 use of (another) named technique to sample invertebrates ;\n5 use an expert / (identification) app / guidebook (instead of an identification key) ;\n\n2(b)(ii) 1 (for Tipula limbata) n / N = 0.083 and (n / N)2 = 0.007 ; 3\n2  = 0.270 ;\n3 D = 0.730 ;\n\n2(b)(iii) peat bog A has (slightly) higher (biodiversity than peat bog B) ; ora 1\n© Cambridge University Press & Assessment 2024 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2024-Oct-Nov/ms/9700_w24_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2024-oct-nov/9700_w24_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w24_ms_53-p09.png", "../answer-assets/9700_w24_ms_53-p10.png" ] }, { "id": "9700-2025-m-42-q01", "question_id": "9700-2025-m-42-q01", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "1(a) all three correct = 1 mark ; 1\nenergy value / kJ g–1\ntype of respiratory\nsubstrate\napproximately 17 approximately 37\ncarbohydrate ✓\nlipid ✓\nprotein ✓\n\n1(b)(i) respirometer ; 1\n\n1(b)(ii) to, absorb / remove, carbon dioxide ; 1\n\n1(c)(i) 3 ; 1\n\n1(c)(ii) 1.33 ; ecf from (b)(i) 1\n\n1(d)(i) any three from: 3\n1 RQ value falls ;\n2 data quote ;\nRQ = 0.9 at, start of torpor / 8:00 or maximum RQ = 0.98\nand\nRQ = 0.75 at, end of torpor / 17:12\n3 respires / metabolises, lipid / protein ;\n4 AVP ; e.g. running out of available, carbohydrate / glycogen\n© Cambridge University Press & Assessment 2025 Page 5 of 19\n\n1(d)(ii) any two from: 2\n1 during, winter / cold weather, when food is limited / to conserve energy / to reduce heat loss / AW ;\n2 during, summer / hot weather / dry conditions, to, conserve water / prevent overheating ;\n3 to avoid predation ;\n4 AVP ; e.g. factor plus reason\nQuestion Answer Marks", "source_pages": [ 5, 6 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p05.png", "../answer-assets/9700_m25_ms_42-p06.png" ] }, { "id": "9700-2025-m-42-q02", "question_id": "9700-2025-m-42-q02", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) no geographical separation / AW ; 1\n\n2(a)(ii) any three from: 3\n1 do not, interbreed / interact / recognise each other ;\n2 due to differences in, courtship / mating ; e.g. mating calls / time of year\n3 different group sizes ; A description (e.g. groups vs solitary)\n4 different, hunting / feeding / diets ;\n© Cambridge University Press & Assessment 2025 Page 6 of 19\n\n2(b)(i) any one from: 1\n1 no black patch on, top of body / back ;\n2 small eyepatch ;\n3 grey patch just behind dorsal fin ;\n4 taller dorsal fin ;\n5 larger pale patch on underside near tail ;\n6 bulbous / rounded / squarer, head ;\n\n2(b)(ii) any three from: 3\n1 population, isolated from other populations / migrated ;\n2 small (starting) population ;\n3 small gene pool / low genetic diversity ;\n4 reference to, chance / founder effect ;\n5 change in allele frequency / some alleles lost ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 7 of 19\n\n2(c) any two from: 2\n1 habitat, size / destruction / disturbance / pollution ;\n2 hunting (by humans) ;\n3 reference to food source ;\n4 measure sea temperature ;\n5 genetic diversity / inbreeding ;\n6/7 AVP ; ; e.g. geographical range / migration patterns / movements / disease / breeding frequency / mortality rate\n© Cambridge University Press & Assessment 2025 Page 8 of 19", "source_pages": [ 6, 7, 8 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p06.png", "../answer-assets/9700_m25_ms_42-p07.png", "../answer-assets/9700_m25_ms_42-p08.png" ] }, { "id": "9700-2025-m-42-q03", "question_id": "9700-2025-m-42-q03", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "3(a)(i) any four from: 4\n1 DNA polymerase ;\n2 synthesises, complementary / new, DNA strand ;\n3 binds to primers on (target) DNA ;\n4 adds (DNA) nucleotides to the end of primers\nor\nused in extension stage ;\n5 (optimum) working temperature of 72 °C ; A 70–75 °C\n6 thermostable / does not denature at 95 °C ;\n7 (so) can be used for many PCR cycles / does not need replacing ;\n8 AVP ; e.g. forming phosphodiester bonds (between adjacent nucleotides)\n\n3(a)(ii) (child) 2 and (child) 3 ; 1\n\n3(a)(iii) any three from: 4\n1 separates DNA fragments of different, sizes / lengths / mass ;\n2 DNA fragments are negatively charged ;\n3 (so) DNA fragments move (from cathode) to anode ;\n4 smaller DNA fragments migrate, faster / further ; ora\n5 DNA fragments from, normal (MT-RNR1) gene travels shorter distance ; ora\n\n3(b) horizontal transmission / transfer plasmids / conjugation / transduction / transfection / transformation ; 1\n© Cambridge University Press & Assessment 2025 Page 9 of 19", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p09.png" ] }, { "id": "9700-2025-m-42-q04", "question_id": "9700-2025-m-42-q04", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 15, "status": "available", "reason": null, "text": "4(a) parental gametes H h  H h ; accept from Punnett square 3\noffspring genotypes HH Hh Hh hh ; accept from Punnett square\noffspring phenotypes no disease disease / ;\nhaemochromatosis\n\n4(b) any two from: 2\n1 reference to using knowledge of DNA sequence of, HFE gene / C282Y (mutation) ;\n2 (from) databases / bioinformatics ;\n3 (to) find / identify, the, HFE gene / C282Y (mutation), in fossil DNA sequences ;\n4 compare DNA sequence of fossil HFE gene with (sequence for), normal HFE allele / C282Y (mutation) ;\n\n4(c)(i) any four from: 4\n1 low, iron / meat, (in diet), acts as a selection pressure ;\n2 people, with, C282Y / mutant allele, absorb more iron ;\n3 (so), survive / reproduce ;\n4 idea that (allele) frequency of mutant allele increased in the population ;\n5 natural selection ;\n6 (named) heterozygote advantage ; e.g. less likely to be iron deficient / not get haemochromatosis ;\n7 AVP ; e.g. C282Y (in heterozygotes) is neutral in present-day diets (so maintained)\nor gives protection from other diseases\n© Cambridge University Press & Assessment 2025 Page 10 of 19\n\n4(c)(ii) any three from: 3\n1 highest / AW, percentage in Ireland where it first occurred ;\n2 higher percentages nearer Ireland due to migration ; ora\n3 migration affected by, barriers / borders ;\n4 type of diet ;\n5 different treatments available (for hereditary haemochromatosis) in different countries ;\n6 AVP ;\n\n4(d) any valid difference ; e.g. small database / ethnicity / region / location 1\n\n4(e) 282 ; ; 2\nif answer is incorrect allow 1 mark for correctly calculating the number of heterozygotes from incorrect 2pq\ni.e. 2501  incorrect 2pq\n© Cambridge University Press & Assessment 2025 Page 11 of 19", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p10.png", "../answer-assets/9700_m25_ms_42-p11.png" ] }, { "id": "9700-2025-m-42-q05", "question_id": "9700-2025-m-42-q05", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 5, "status": "available", "reason": null, "text": "5 any five from: 5\n1 (meiosis) II ;\n2 two cells are visible / four groups of chromosomes ;\n3 anaphase ;\n4 as two groups of chromosomes per daughter cell ;\n5 centromeres / kinetochores, attached to, spindle fibres / microtubules ;\n6 spindle fibres / microtubules, shorten / contract ;\n7 to pull, (daughter) chromosomes / (sister) chromatids, to opposite poles / described ;\n8 the centromeres lead with the chromosome arms following behind / AW ;\n9 reference to no nuclear envelope ;\nQuestion Answer Marks", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p12.png" ] }, { "id": "9700-2025-m-42-q06", "question_id": "9700-2025-m-42-q06", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) P – insulin ; 3\nQ – muscle / liver ;\nR – glycogen ;\n\n6(a)(ii) negative feedback ; 1\n© Cambridge University Press & Assessment 2025 Page 12 of 19\n\n6(b) any seven from: 7\n1 glucagon ;\n2 binds to receptor on cell surface membrane (of liver cell) ;\n3 G-protein activated ;\n4 adenyl(yl) cyclase activated ;\n5 ATP converted to cAMP ;\n6 second messenger ;\n7 enzyme cascade / described ;\n8 enzymes activated by phosphorylation ;\n9 signal amplified ;\n10 glycogen broken down into glucose / glycogenolysis ;\n11 glucose enters blood ;\n12 gluconeogenesis / described ;\n© Cambridge University Press & Assessment 2025 Page 13 of 19", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p12.png", "../answer-assets/9700_m25_ms_42-p13.png" ] }, { "id": "9700-2025-m-42-q07", "question_id": "9700-2025-m-42-q07", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 13, "status": "available", "reason": null, "text": "7(a)(i) 10.8 (year–1) ; ; 2\nif value for rate is incorrect allow 1 mark for:\n1010−470 540\nor\n50 50\n\n7(a)(ii) any three from: 3\n1 ban, hunting / poaching / trade ;\n2 enforcement / strict penalties ;\n3 national parks / protected reserves / habitat protection / AW ;\n4 tracking devices / monitoring ;\n5 raise awareness / education ;\n6 AVP ; e.g. veterinary care\n© Cambridge University Press & Assessment 2025 Page 14 of 19\n\n7(b) any four from: 4\n1 maintain, gene pool / genetic diversity ;\n2 ecotourism ;\n3 ethical / moral, reasons ;\n4 reference to effect on, ecosystems / food chains / food webs ;\n5 aesthetic reasons ;\n6 idea of research ;\n7 cultural significance ;\n8 pollination ;\n9 AVP ; e.g. keystone species\n© Cambridge University Press & Assessment 2025 Page 15 of 19\n\n7(c) 4\ncorrect order letter\n1 C\n2 G\n3 A\n4 F\n5 D\n6 B\n7 E\nCGA in correct order ; ignore intervening letters\nCGA above F ;\nDBE in correct order ;ignore intervening letters\nDBE below F ;\nQuestion Answer Marks", "source_pages": [ 14, 15, 16 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p14.png", "../answer-assets/9700_m25_ms_42-p15.png", "../answer-assets/9700_m25_ms_42-p16.png" ] }, { "id": "9700-2025-m-42-q08", "question_id": "9700-2025-m-42-q08", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "8(a) decarboxylation ; 2\ndehydrogenation / oxidation ;\n© Cambridge University Press & Assessment 2025 Page 16 of 19\n\n8(b) any four from: 4\n1 reduces activity of citrate synthase\nor\nactivity of citrate synthase is higher without succinyl-coA than with succinyl-coA ;\n2 comparative data quote ;\n3 succinyl-coA binds to citrate synthase active site ;\n4 succinyl-coA acts as a competitive inhibitor / described ;\n5 slows down Krebs cycle ;\n6 prevents build up / reduces production, of, citrate / intermediates ;\n7 AVP ;\n\n8(c) any four from: 4\n1 hydrogen carrier / reduced ;\n2 in, link reaction / Krebs cycle ;\n3 moves to, inner mitochondrial membrane / cristae ;\n4 releases hydrogen (atoms) ; A protons and electrons\n5 for use in, oxidative phosphorylation ;\n6 NAD, oxidised / recycled ;\n© Cambridge University Press & Assessment 2025 Page 17 of 19", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p16.png", "../answer-assets/9700_m25_ms_42-p17.png" ] }, { "id": "9700-2025-m-42-q09", "question_id": "9700-2025-m-42-q09", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 9, "status": "available", "reason": null, "text": "9(a) any two from: 2\n1 accessory pigment ;\n2 absorbs light wavelengths not absorbed by, reaction centre / primary pigment / chlorophyll a ;\n3 so extends the range of wavelengths absorbed ;\n4 pass energy to, reaction centre / primary pigment / chlorophyll a ;\n5 idea that improves efficiency of light-dependent stage ;\n\n9(b)(i) 1 rate of photosynthesis / rate of oxygen production, increases then levels off in both (plants) ; 3\n2 rate of mutant plants higher than rate of normal plants ;\n3 comparative data quote ;\n\n9(b)(ii) any four from: 4\n1 absorbs more light ;\n2 so faster rate of, photosynthesis / light-dependent stage ;\n3 more ATP and reduced NADP produced ;\n4 more turns of Calvin cycle / AW ;\n5 more, triose phosophate / TP, produced ;\n6 more, hexose/ AW, for respiration ;\n7 more energy for growth ;\n8 more synthesis of, amino acids / proteins / lipids / cellulose / starch ;\n© Cambridge University Press & Assessment 2025 Page 18 of 19", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p18.png" ] }, { "id": "9700-2025-m-42-q10", "question_id": "9700-2025-m-42-q10", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 Na+ (ions) enter cell ;\n2 through channels / by facilitated diffusion ;\n3 depolarisation of cell surface membrane ;\n4 reference to, receptor potential / threshold ;\n5 Ca2+ channels open / Ca2+ enter cell ;\n6 vesicles with neurotransmitter move towards cell surface membrane ;\n7 vesicles fuse with cell surface membrane and release neurotransmitter / exocytosis ;\n\n10(b) any three from: 3\n1 albino / albinism\nor\ndescribed ; e.g. no pigment or melanin in skin / pale skin / white hair\n2 poor vision\nor\ndescribed ; e.g. red or pink eyes / irises, eyes sensitive to light / jerky eye movements\n3 tyrosinase, non-functioning / not produced ;\n4 tyrosine not converted to, DOPA / dopaquinone ;\n5 no melanin produced ;\n© Cambridge University Press & Assessment 2025 Page 19 of 19", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_42-p19.png" ] }, { "id": "9700-2025-m-52-q01", "question_id": "9700-2025-m-52-q01", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 15, "status": "available", "reason": null, "text": "1(a) any three from: 3\n1 catch (a sample of grey bush) crickets (within habitat) and count total captured and mark and release them ;\n2 detail ;\ne.g. idea of suitable marking so not harmful / too obvious / not removed\ne.g. idea of leaving for a few days (to give time for populations to mix before second sample taken)\n3 catch second sample and count total number of crickets and number of marked crickets ;\n4 reference to Lincoln index ;\n\n1(b) Table 1.1 completed correctly and (n / N)2 = 0.21 / 0.22 when answer rounded to 2 significant figures ; 3\nD = 0.78 / 0.79 when rounded to 2 significant figures ;\nD = 0.783 ; must be to 3 significant figures ;\n© Cambridge University Press & Assessment 2025 Page 5 of 10\n\n1(c)(i) any two from: 2\n1 wind, speed / direction ;\n2 (atmospheric) humidity ;\n3 rainfall / soil water content ;\n4 soil type ;\n5 soil pH ;\n6 salinity (of soil) ;\n7 mineral / ion, concentration (of soil) ;\n8 (atmospheric) carbon dioxide concentration ;\n© Cambridge University Press & Assessment 2025 Page 6 of 10\n\n1(c)(ii) any seven from: 7\n1 use quadrats ;\n2 method of, random / systematic, placement of quadrats ;\n3 use, same / stated, size (frame / point), quadrat ;\n4 method of identifying (plant) species ;\n5 count the number of individuals of each (plant) species ;\n6 idea of taking care to note, low growing / small / easy to miss, species ;\n7 idea of sampling, 10 or more / AW, separate points / quadrats (in the grey dune habitat) ;\n8 (measure biodiversity of plant species) at regular intervals (over the 10-year period) and at the same time of the year ;\n9 repeat (whole investigation over 10 years) at different, times of year / seasons ;\n10 named hazard and risk and precaution ;\nhazard risk precaution\nplants / pollen allergy / irritation / injury gloves / eye protection / mask / PPE /\nprotective clothing\nanimals allergy / irritation / injury gloves / eye protection / mask / PPE /\nprotective clothing\ngrey dunes / ecosystem getting lost / trip hazard / wear suitable shoes / clothes / gloves /\ninjury PPE\nstay, in a group / with expert / ranger\n© Cambridge University Press & Assessment 2025 Page 7 of 10", "source_pages": [ 5, 6, 7 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_52-p05.png", "../answer-assets/9700_m25_ms_52-p06.png", "../answer-assets/9700_m25_ms_52-p07.png" ] }, { "id": "9700-2025-m-52-q02", "question_id": "9700-2025-m-52-q02", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 8, "status": "available", "reason": null, "text": "2(a) any two from: 2\n1 data, are ordinal / can be ranked ;\n2 data points within samples are independent of each other ;\n3 there are 20 paired observations ;\n4 coffee farms / sampling points, were selected at random ;\n5 AVP ;\n\n2(b) (there is) no correlation between the water availability and the number of months that elephants entered each (coffee) farm 1\nper year ;\n\n2(c)(i) all correct ; 1\nr value significance\ns\n0.63 yes\n–0.30 no\n0.02 no\n0.38 no\n© Cambridge University Press & Assessment 2025 Page 8 of 10\n\n2(c)(ii) any one from: 1\nnegative correlation / the greater the density of December trees, the fewer the number of months that elephants entered\neach (coffee) farm / ora\nand\n(correlation) is weak / is not significant ;\nthere is no correlation (between the density of December trees and the number of months that elephants entered each\nfarm) ;\n\n2(d) any three from: 3\nsupport:\n1 idea that reducing water availability is (significantly) correlated with a reduced number of times that elephants enter the\n(coffee) farm ;\n2 idea that water availability was the only variable found to be significant (so reducing the number of water bodies might\nbe the most effective action) ; ora\ndoes not support (max 2):\n3 water bodies only counted, once / in March / in 2008 ;\n4 investigation only, in one geographical area (of India) / at Nagarahole National Park ;\n5 idea that size of, ponds / lakes / water holes, might also be important ;\n6 idea that (questionnaire) does not record actual, number of times elephants entered the farms / number of elephants\n(per month) ;\n7 idea that correlation does not indicate causation (so reducing the availability of water may not affect the number of\nelephant visits) ;\n© Cambridge University Press & Assessment 2025 Page 9 of 10", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_52-p08.png", "../answer-assets/9700_m25_ms_52-p09.png" ] }, { "id": "9700-2025-m-52-q03", "question_id": "9700-2025-m-52-q03", "subject": "9700", "year": 2025, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 7, "status": "available", "reason": null, "text": "3(a) independent variable: 2\nvaccinated or not vaccinated (against Rotavirus) ;\ndependent variable:\nnumber of children with (type 1) diabetes (per 100 000 population in Australia) ;\n\n3(b)(i) 1 number of children (aged from 0 to 4 years) with (type 1) diabetes decreased, after the introduction of the vaccine 2\n(against rotavirus) ;\n2 number of children (aged from 0 to 4 years) with (type 1) diabetes increased (slowly) from, 2000 to 2007 / 2008 to 2015\n;\n\n3(b)(ii) any three from: 3\n1 idea that (mean) number of children aged from 0 to 4 years with (type 1) diabetes (per 100 000 population) is lower\nafter introduction of vaccine ;\n2 idea that, (95%) confidence intervals / (95%) CI / error bars (for before and after introduction of vaccine), in children\naged from 0 to 4 years (before and after introduction of vaccine) do not overlap therefore number of children with (type\n1) diabetes is significantly different (before and after introduction of vaccine) ;\n3 10 to 14 year olds act as a control group (because they are not vaccinated against Rotavirus)\nor\n10 to 14 year olds are unvaccinated (before and after introduction of vaccine) ;\n4 idea that, (95%) confidence intervals / (95%) CI / error bars (for before and after introduction of vaccine), in children\naged from 10 to 14 years (before and after introduction of vaccine) overlap, therefore number of (unvaccinated)\nchildren with (type 1) diabetes is not significantly different (before and after introduction of vaccine) ;\n© Cambridge University Press & Assessment 2025 Page 10 of 10", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2025-March/ms/9700_m25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-march/9700_m25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m25_ms_52-p10.png" ] }, { "id": "9700-2025-mj-41-q01", "question_id": "9700-2025-mj-41-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "1(a) any two from: 2\nglucose (phosphate) ;\nfructose (phosphate / bisphosphate) ;\ntriose phosphate ;\n(named) fatty acid / keto-acid ;\nglycerol ;\namino acid ;\n\n1(b) any four from: 4\n1 breaks down / hydrolyses to, ADP / AMP, and Pi ;\n2 releases, energy / 30.5 kJ mol-1 ;\n3 reversible reaction / high turnover / can be regenerated ;\n4 small / soluble, so can, diffuse / move (freely), in cell ;\n5 AVP ;\n\n1(c) substrate-linked / substrate-level (phosphorylation) ; 1\n\n1(d)(i) oxygen ; 1\n\n1(d)(ii) presence of oxygen: 3\n1 (ATP yield) increases / is higher ;\nplus any two from:\n2 oxygen acts as final, electron / proton, acceptor ;\n3 oxidative phosphorylation / chemiosmosis (occurs) ;\n4 energy from, reduced NAD / reduced FAD / electron transport chain ;\n5 proton gradient / H+ → into intermembrane space ;\n6 ATP made in Krebs cycle ;\n© Cambridge University Press & Assessment 2025 Page 8 of 17", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p08.png" ] }, { "id": "9700-2025-mj-41-q02", "question_id": "9700-2025-mj-41-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 5, "status": "available", "reason": null, "text": "2(a) any four from: 4\n1 sodium hydroxide absorbs, carbon dioxide / CO , released by, woodlice / respiration ;\n2\n2 oxygen / O , taken in reduces pressure (in boiling tube) ;\n2\n3 drop of liquid moves towards, boiling tube / bung / woodlice / left ;\n4 measure, distance / length, moved by drop, in set time ;\n5 rate = distance divided by time ;\n6 detail of calculation of volume of O used ;\n2\n\n2(b) rate at 5 °C: 1\nlower / slower\nand\nless / lower, kinetic energy\nor\nfewer enzyme-substrate, collisions / complexes\nor\nfewer, enzyme-catalysed / respiration / glycolysis / link reaction / Krebs cycle, reactions ;\nQuestion Answer Marks", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p09.png" ] }, { "id": "9700-2025-mj-41-q03", "question_id": "9700-2025-mj-41-q03", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 13, "status": "available", "reason": null, "text": "3(a) dominant ; 2\n3 / daughter, has disease but, 2 / father, does not\nor\n3 / daughter, could not have the disease if allele were recessive ;\n\n3(b) any three from: 3\n1 founder effect ;\n2 allele / variegate porphyria, present in, migrants / settlers / founding population ;\n3 higher frequency than in, Dutch / Europeans / original population ;\n4 genetic drift has large effect in small, population / gene pool ;\n5 inbreeding / migrants married within their own population ;\n6 high frequency of allele maintained over, time / generations ;\n7 AVP ;\n© Cambridge University Press & Assessment 2025 Page 9 of 17\n\n3(c) any four from: 4\n1 use mRNA (from person’s cells) to make, cDNA / ssDNA ;\n2 add fluorescent, label / tag / dye / chemical / marker, to (this ss) DNA ;\n3 cDNA / ssDNA, hybridises with / binds to / complementary base pairs with, probe(s) / microarray ;\n4 fluorescence shows, disease / mutant, gene / allele, expression / transcription ;\n5 AVP ;\n\n3(d) any one from: 1\n1 find out / diagnose, person’s disease ;\n2 so can, choose / develop, right treatment ;\n3 global, research resource / access ;\n\n3(e) any three from: 3\n1 change from T to C\nor\nreplacement / substitution, of T, with / by, C\nor\nsubstitution of C for T ;\n2 functional / working / correct / normal, enzyme / protein, produced ;\n3 gRNA, is specific to / only finds / just alters, CEP /disease / mutant, allele / gene\nor\ngRNA does not bind to genes other than CEP ;\n4 AVP ;\n© Cambridge University Press & Assessment 2025 Page 10 of 17", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p09.png", "../answer-assets/9700_s25_ms_41-p10.png" ] }, { "id": "9700-2025-mj-41-q04", "question_id": "9700-2025-mj-41-q04", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 14, "status": "available", "reason": null, "text": "4(a) any three from: 3\n(both processes)\n1 use / require, carbon dioxide / CO ;\n2\n2 use / require, water / H O ;\n2\n3 use / require, (sun) light energy / source of energy is light ;\n4 make an organic, molecule / product ;\n5 produce / release, oxygen / O ;\n2\n6 involve transduction of energy (from one form to another) ;\n7 involve electron flow ;\n\n4(b) A starch, grain / granule ; 2\nB thylakoid (membrane) / lamella / granum ;\n\n4(c)(i) ATP and reduced NADP (and oxygen) ; 1\n\n4(c)(ii) any four from: 4\n1 electron carriers / electron transport chain / to carry electrons ;\n2 to release energy to, move / pump, protons (into, thylakoid space / lumen)\nor\nto release energy to generate proton gradient ;\n3 oxygen-evolving, complex / enzyme ;\n4 (to catalyse) splitting / photolysis, of water ;\n5 LHC / antenna complex / photosystem, proteins hold pigments ;\n6 ATP synth(et)ase to make ATP ;\n\n4(d) triose phosphate ; 1\n© Cambridge University Press & Assessment 2025 Page 11 of 17\n\n4(e) any two plus one opposing arguments based on correct ref. to: 3\n1 percentage / amount, of sunlight, absorbed / used ;\n2 absorption / action, spectrum\nor\nwavelengths / colours of light, used ;\n3 respiration of organism ;\n4, 5 stage/transition, where, energy lost ; ;\n6, 7 (named) limiting factor(s) ; ;\n8 energy storage capability\nor\nnight / dark, process ;\n9 quality / nutrition in / palatability, of food product ;\n10 proportion edible ;\n11,12 additional energy inputs ; ;\n13, 14 additional resources needed ; ;\n15 labour / maintenance, needed ;\n16 amount of space needed ;\n17 plant, hormones / coordination ;\n18 evolutionary adaptation ;\n© Cambridge University Press & Assessment 2025 Page 12 of 17", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p11.png", "../answer-assets/9700_s25_ms_41-p12.png" ] }, { "id": "9700-2025-mj-41-q05", "question_id": "9700-2025-mj-41-q05", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 14, "status": "available", "reason": null, "text": "5(a)(i) directional (selection) ; 1\n\n5(a)(ii) curve with starting point (on x-axis), peak and end point (on x-axis) all to the right of the original positions ; 1\n\n5(b) any four from: 4\n1 disruptive / diversifying (selection) ;\n2 selection pressure is, seed / food (availability / size) ;\n3 competition for, food / seeds ;\n4 (birds with) intermediate bills cannot eat small and large seeds ;\n5 extreme / small and large, phenotypes / bills, more likely to survive / have selective advantage / selected for ;\n6 correct description of change in allele frequency ;\n\n5(c)(i) r / 0.930 / calculated value, is greater than critical value for n = 5 ; 2\nat (probability level) 0.05 ;\n\n5(c)(ii) any four from: 4\ninvasive alien species / they, may:\n1 change / disrupt, food, chains / webs ;\n2 compete for food with / feed on same food as / occupy same niche as, native, species / organisms ;\n3 prey on / graze / eat, native, species / organisms ;\n4 introduce (new), disease / parasites ;\n5 change / damage, the habitat ;\n6 be toxic / threaten human health ;\n7 damage, tourism / agriculture ;\n\n5(c)(iii) any two from: 2\n1 climate change ;\n2 hunting by humans ;\n3 degradation / loss, of habitat ;\n4 (named) pollution ;\n5 disease ;\n6 (named) natural disasters ;\n© Cambridge University Press & Assessment 2025 Page 13 of 17", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p13.png" ] }, { "id": "9700-2025-mj-41-q06", "question_id": "9700-2025-mj-41-q06", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "6(a)(i) P: selective reabsorption ; 3\nQ: osmoregulation ;\nR: ultrafiltration ;\n\n6(a)(ii) P: proximal convoluted tubule ; 3\nQ: collecting duct / distal convoluted tubule ;\nR: Bowman’s capsule ;\n\n6(b) 1 B / interstitial fluid / tissue fluid / medulla, has more, salt / sodium chloride / Na+ / Cl–; 2\nplus one from:\n2 salt gradient helps reabsorb water from collecting duct ;\n3 AVP ;\nQuestion Answer Marks", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p14.png" ] }, { "id": "9700-2025-mj-41-q07", "question_id": "9700-2025-mj-41-q07", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "7(a) any four from: 4\n1 insulin / it, is a hormone ;\n2 (described) stimulus causes insulin to be secreted from (named) endocrine, gland / tissue / cells ;\n3 insulin travels in blood ;\n4 binds to receptors on (named) target cells ;\n5 to cause (described) response ;\n6 AVP ;\n\n7(b)(i) any four from: 4\n1 at 21 min, blood glucose concentration / it, rises to 110 mg 100 cm–3 ;\n2 (high / increase in, blood glucose concentration) detected by pancreas / causes response in pancreas ;\n3 insulin rises to 500 pmol dm-3 ;\n4 (insulin) increase GLUT proteins in membrane / increases glucose uptake into cells / increases cell permeability to\nglucose\nor\n(insulin) increases rate of respiration of glucose ;\n5 (insulin) causes / stimulates, glycogenesis / lipogenesis ;\n6 (mean) blood glucose concentration / it, falls, to normal / within normal range / below starting point / to set point ;\n© Cambridge University Press & Assessment 2025 Page 14 of 17\n\n7(b)(ii) any three from: 3\n1 blood glucose concentration falls as glucose is respired ;\n2 blood glucose concentration falls below, set point / normal ;\n3 insulin, secretion / release, stops ;\n4 glucagon (secreted / released / rises) ;\n5 glycogen, (in cells) converted to glucose\nor\nglycogenolysis ;\n6 (stored) protein / fat, converted to glucose\nor\ngluconeogenesis\nor\n(stored) protein / fat, used for respiration ;\nQuestion Answer Marks", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p14.png", "../answer-assets/9700_s25_ms_41-p15.png" ] }, { "id": "9700-2025-mj-41-q08", "question_id": "9700-2025-mj-41-q08", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 6, "status": "available", "reason": null, "text": "8 any six from: 6\n1 gibberellin binds to (gibberellin) receptor (-enzyme-complex) ;\n2 DELLA (protein) destroyed ;\n3 transcription factor / PIF, released / free / no longer bound to DELLA ;\n4 transcription factor / PIF / RNA polymerase, binds to, DNA / promoter ;\n5 growth / expansion / XET / xyloglucan endotransglucosylase, gene, switched on / expressed / transcribed ;\n6 loosens cell walls / breaks bonds between cellulose ;\n7 water enters (cells) by osmosis causing cell elongation ;\n8 AVP ;\n© Cambridge University Press & Assessment 2025 Page 15 of 17", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p15.png" ] }, { "id": "9700-2025-mj-41-q09", "question_id": "9700-2025-mj-41-q09", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 6, "status": "available", "reason": null, "text": "9(a) any three from: 3\n1 (domains are) Archaea and Bacteria ;\n2 membrane lipids ester-linked (Bacteria) vs. ether-linked / not ester-linked (Archaea) ;\n3 single type of rRNA (Bacteria) vs. 3 types (Archaea)\nor\nArchaea, rRNA / ribosomal subunit, similar to eukaryotic ;\n4 peptidoglycan (Bacteria) vs. not peptidoglycan / different (Archaea) ;\n5 AVP ;\n\n9(b) 3\ntaxon name\ndomain Eukarya ;\nkingdom Animalia ;\nphylum Chordata\nclass Mammalia\norder Carnivora\nfamily Felidae\ngenus Panthera ;\n© Cambridge University Press & Assessment 2025 Page 16 of 17", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p16.png" ] }, { "id": "9700-2025-mj-41-q10", "question_id": "9700-2025-mj-41-q10", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 12, "status": "available", "reason": null, "text": "10(a) causing X / –70 (mV) any three from: 7\n1 active transport / sodium-potassium pump ;\n2 moves three Na+ out of and two K+ in (to neurone) ;\n3 more K+ diffuses out than Na+ diffuses in ;\n4 makes outside of membrane (relatively) more positive ;\n5 maintaining / establishing, resting potential ;\ncausing Y / +40 (mV) any two from:\n6 depolarisation ;\n7 Na+ / sodium ion, channels open ;\n8 Na+, moves / diffuses, in (to neurone) ;\ncausing Z / –90 (mV) any two from:\n9 hyperpolarisation ;\n10 (voltage-gated) K+ / potassium ion, channels open ;\n11 K+, moves / diffuses, out (of neurone) ;\n\n10(b) 1 local, circuit / current ; 2\n2 from, depolarised / positive, area to, resting / negative, area ;\n\n10(c) any three from: 3\n1 speeds up (nerve) impulse / impulse transmission faster ;\n2 (as) myelin sheath / Schwann cells, act(s) as an insulator ;\n3 (as) local circuits flow between, nodes of Ranvier / gaps in sheath ;\n4 saltatory conduction ;\n5 fast(er), (described) response / muscle contraction ;\n© Cambridge University Press & Assessment 2025 Page 17 of 17", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_41-p17.png" ] }, { "id": "9700-2025-mj-42-q01", "question_id": "9700-2025-mj-42-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "1(a)(i) 2 ; 1\n\n1(a)(ii) pumps / actively transports, protons / hydrogen ions, into intermembrane space ; 2\nref. to proton gradient ;\n\n1(a)(iii) any three from: 3\n1 ATP synthase ;\n2 protons / hydrogen ions, move (from intermembrane space) to matrix ;\n3 by facilitated diffusion ;\n4 ATP synthesised from ADP + Pi ; A ADP is phosphorylated to ATP\n5 ref. to chemiosmosis ;\n© Cambridge University Press & Assessment 2025 Page 8 of 25\n\n1(b) any four from: 4\n1 electron transport chain / ETC, stops / reduced ;\n2 oxygen does not act as (final) electron acceptor ;\n3 no / less , protons pumped into intermembrane space\nor\nno / less steep, proton gradient ;\n4 build-up of, reduced NAD / reduced FAD\nor\nno / less, reduced NAD / reduced FAD, oxidised / recycled\nor\nno / less, NAD / FAD, regenerate / recycled ;\n5 no / less, ATP production\nor\nno / fewer, protons pass through ATP synthase ;\n6 Krebs cycle / link reaction / oxidative phosphorylation, stops / reduced ;\n7 ref. to glycolysis / anaerobic respiration / lactate produced / ethanol produced / substrate level phosphorylation ;\n© Cambridge University Press & Assessment 2025 Page 9 of 25", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p08.png", "../answer-assets/9700_s25_ms_42-p09.png" ] }, { "id": "9700-2025-mj-42-q02", "question_id": "9700-2025-mj-42-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 6, "status": "available", "reason": null, "text": "2 any six from: 6\nfor either\n1 random / chance (event) ;\n2 not (natural) selection / not caused by selection pressure ;\n3 loss of (some) alleles ; I loss of gene\n4 (so) increase in frequency of, one / small number of, allele(s)\nor\nincrease in homozygosity / decrease in heterozygosity ;\n5 small(er) gene pool / reduction in genetic variation ;\ngenetic drift\n6 (random), fusion of gametes / mating / death of individual / mutation ;\n7 larger effect in small population ;\nfounder effect\n8 small number of individuals, isolated / start new population / migrate ;\n9 not all alleles present from original population / alleles not representative of original population ;\n10 AVP ; e.g. ref. to bottleneck effect genetic drift occurs gradually over time founder effect is a one-off event\n© Cambridge University Press & Assessment 2025 Page 10 of 25", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p10.png" ] }, { "id": "9700-2025-mj-42-q03", "question_id": "9700-2025-mj-42-q03", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 14, "status": "available", "reason": null, "text": "3(a)(i) F1 genotypes: AaBb x AaBb ; 5\ngametes: AB Ab aB ab (AB Ab aB ab) ;\nF2 genotypes:\nAB Ab aB ab\nAB AABB AABb AaBB AaBb\nawn awn awn Awn\nAb AABb AAbb AaBb Aabb\nawn awn awn awn\naB AaBB AaBb aaBB aaBb\nawn awn awn awn\nab AaBb Aabb aaBb aabb ;\nawn awn awn no awn\nF2 phenotypes linked to genotypes (see Punnet Square) ;\nratio of F2 phenotypes: 15:1\nawn: no awn ;\n\n3(a)(ii) autosomal dominant / epistasis ; 1\nI dihybrid\n© Cambridge University Press & Assessment 2025 Page 11 of 25\n\n3(b) any one from: 1\nfor seed dispersal ;\nidea of protection ;\nanchor into the ground ;\nobtain more, nutrients / water ;\n\n3(c)(i) any four from: 4\n1 artificial selection / selective breeding / humans act as selection pressure ;\n2 select (rice) plants / seeds / grains, with no awns ;\n3 idea of breeding (selected) plants / self pollination of (selected) plants ;\n4 seeds germinate / plants grow / offspring grow ;\n5 repeat (selection and breeding) over generations ;\n6 AVP ; e.g. ref. to genetic technology detail of pollination\n© Cambridge University Press & Assessment 2025 Page 12 of 25\n\n3(c)(ii) any three from: 3\n1 mutation / change in base sequence, (in An-1)\nor\nAn-1 not expressed ;\n2 transcription factor has different, primary structure / tertiary structure / 3D shape\nor\ntranscription factor not, produced / functional\nor\ntranscription factor faulty ;\n3 transcription factor does not bind to, the promoter / DNA ;\n4 decrease in expression of gene(s) for awn development ;\n5 increase in expression of gene(s) for number of grains produced ;\nQuestion Answer Marks", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p11.png", "../answer-assets/9700_s25_ms_42-p12.png", "../answer-assets/9700_s25_ms_42-p13.png" ] }, { "id": "9700-2025-mj-42-q04", "question_id": "9700-2025-mj-42-q04", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "4(a) any three from: 3\n1 (diploid) cell formed from (two) haploid gametes ;\n2 (diploid) cell has two sets of chromosomes / one set of chromosomes from each gamete ;\n3 (homologous chromosomes) maternal and paternal chromosomes ;\n4 (homologous chromosomes) has same, genes / loci / banding pattern / centromere position / size / length ;\n\n4(b) anaphase 1 / telophase 1 ; 2\nseparation of, homologous chromosomes / bivalent ;\n© Cambridge University Press & Assessment 2025 Page 13 of 25\n\n4(c)(i) Fig. 4.1 2\nmetaphase 2 ; A anaphase 2\nFig. 4.2\ntelophase 1 ; A anaphase 1\n\n4(c)(ii) 48 ; 1\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p13.png", "../answer-assets/9700_s25_ms_42-p14.png" ] }, { "id": "9700-2025-mj-42-q05", "question_id": "9700-2025-mj-42-q05", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "5(a) any four from: 4\n1 find, nucleotide / base / gene / DNA, sequence ;\n2 from database / using bioinformatics / from gene library ;\n3 make the gene (chemically) using nucleotides ;\n4 extract mRNA from cell, making the protein / expressing the gene ;\n5 use reverse transcriptase (with mRNA) to make cDNA ;\n6 use DNA polymerase (with cDNA) to make dsDNA ;\n7 cut out / extract / isolate, the gene from DNA ;\n8 using restriction enzyme ;\n© Cambridge University Press & Assessment 2025 Page 14 of 25\n\n5(b) any three from: 3\nora for animal insulin\n1 large scale supply / supply can match demand ;\n2 no / less, likely to cause, immune / allergic, response\nor\nfewer side-effects ;\n3 faster to act / smaller dose needed ;\n4 no / less, likely for (insulin) tolerance to occur ;\n5 no / less, risk of infection / disease ;\n6 no / less, ethical / religious objections\nor\nsuitable for, vegetarians / vegans ;\n7 AVP ; e.g. cheaper to produce / easier to purify\n\n5(c) DNA from two different sources (joined together) 1\nor\nDNA from (human) gene joined to DNA from, bacteria / plasmid ;\n© Cambridge University Press & Assessment 2025 Page 15 of 25\n\n5(d) any four from: 4\n1 find, nucleotide / base / gene / DNA, sequence (of human insulin gene) ;\n2 from database / using bioinformatics / from gene library ;\n3 gene editing ;\n4 insertion / deletion / replacement, of nucleotide(s) ;\n5. at specific sites (of the gene) ;\n6 (results in) changes to the, (DNA) triplet / codon ;\n7 (so codes for a) different amino acid ;\n8 AVP ; e.g. detail of gene editing / CRISPR / Cas9\n© Cambridge University Press & Assessment 2025 Page 16 of 25", "source_pages": [ 14, 15, 16 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p14.png", "../answer-assets/9700_s25_ms_42-p15.png", "../answer-assets/9700_s25_ms_42-p16.png" ] }, { "id": "9700-2025-mj-42-q06", "question_id": "9700-2025-mj-42-q06", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "6(a) any four from: 4\n1 variable thickness of cell wall described ;\n2 no plasmodesmata (between guard cell and other epidermal cells) ;\n3 many, chloroplasts / mitochondria ;\n4 chloroplasts have few grana ;\n5 mitochondria have many cristae ;\n6 cell surface membrane, often folded / contains many transport proteins ;\n7 AVP ; e.g. cellulose microfibrils arranged in bands / shape description has several small vacuoles nucleus is relatively\nlarger than in mesophyll cells\n\n6(b)(i) 1 (more) stomata open at (mid)day 2\nand\n(more) stomata closed, at (mid)night / in darkness – ora ;\n2 data quote – two values of time of day and percentage of stomata open ;\ntime of day percentage of mean\nstomata open percentage\n( 0.5)\n06:00 90 / 80 / 64 78\n12:00 / midday 93 / 70 / 90 84.3\nand\n18:00 25 / 35 30\n24:00 / midnight 10 / 15 / 10 11.7\n© Cambridge University Press & Assessment 2025 Page 17 of 25\n\n6(b)(ii) any two from: 2\n1 water stress / drought ;\n2 high temperature ;\n3 low humidity / dry (atmosphere);\n4 high carbon dioxide concentration in leaf (air spaces) ;\n5 low light intensity ;\n6 high wind speed ;\n© Cambridge University Press & Assessment 2025 Page 18 of 25\n\n6(c) 4\ncorrect order letter of event\n1 D\n2 E\n3 G\n4 B\n5 F\n6 J\n7 I\n8 A\n9 H\n10 C\nE G B between D and F ;\nE G B in correct order throughout table ;\nJ I A H between F and C ;\nJ I A H in correct order throughout table ;\n© Cambridge University Press & Assessment 2025 Page 19 of 25", "source_pages": [ 17, 18, 19 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p17.png", "../answer-assets/9700_s25_ms_42-p18.png", "../answer-assets/9700_s25_ms_42-p19.png" ] }, { "id": "9700-2025-mj-42-q07", "question_id": "9700-2025-mj-42-q07", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 11, "status": "available", "reason": null, "text": "7(a) any six from: 6\n1 sodium–potassium pumps (in axon membrane) ;\n2 transport, sodium ions / Na+, out and, potassium ions / K+, in ;\n3 by active transport / uses ATP ;\n4 three, sodium ions / Na+, and two, potassium ions / K+ ;\n5 sets up an electrochemical gradient ;\n6 potassium ions / K+, diffuse out through channels ;\n7 membrane more permeable to K+ / membrane has more K+ channels ;\n8 (so) more, potassium ions / K+, move out of axon than, sodium ions / Na+, move in ;\n9 ref. to anions / negatively charged ions / negatively charged proteins, inside ;\n10 inside negative (relative to outside) ;\n11 -60 mV to -70 mV ;\n© Cambridge University Press & Assessment 2025 Page 20 of 25\n\n7(b)(i) any three from: 3\nhypokalaemia ora for normal\n1 longer, action potential / depolarisation / repolarisation\nor\nlarger depolarisation ;\n2 longer hyperpolarisation\nor\nmore negative / smaller, hyperpolarisation ;\n3 longer refractory period ;\n4 more negative / lower, resting potential ;\n5 data quote ;\nnormal hypokalaemia\nmp1 longer action potential 2.6 ms 3.25 ms\nmp1 longer depolarisation 1.0 ms 1.25 ms\nmp1 longer repolarisation 1.0 ms 1.3 ms\nmp1 larger depolarisation 110 mV 140 mV\nmp2 longer hyperpolarisation 0.7 ms 1.0 ms\nmp2 more negative –92 mV –112 mV\nhyperpolarisation –22 mV –12 mV\nmp2 smaller hyperpolarisation\nmp4 resting potential –70 mV –100 mV\n© Cambridge University Press & Assessment 2025 Page 21 of 25\n\n7(b)(ii) any two from: 2\n1 harder stimulus / larger stimulus / larger depolarisation, needed, to reach threshold required / to generate an action\npotential ;\n2 fewer, impulses / action potentials, transmitted\nor\nlower frequency of impulses ;\n3 slower, nervous coordination / reaction times / responses / cognition\nor\nweaker, sensation / muscle contraction ; allow named examples\nQuestion Answer Marks", "source_pages": [ 20, 21, 22 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p20.png", "../answer-assets/9700_s25_ms_42-p21.png", "../answer-assets/9700_s25_ms_42-p22.png" ] }, { "id": "9700-2025-mj-42-q08", "question_id": "9700-2025-mj-42-q08", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "8(a) any four from: 4\n1 eukaryotic / have nucleus ;\n2 no, chlorophyll / chloroplasts ;\n3 heterotrophic / saprophytic / saprotrophic / parasitic / described ;\n4 cell wall made of, chitin / mannoproteins / glucans ;\n5 reproduce by spores ;\n6 hyphae / mycelium ;\n7 cells may be multinucleate ;\n8 either unicellular or multicellular ;\n\n8(b) fungus receives, (named) organic compounds / nutrients / food / oxygen ; 2\nalga receives, support / stability / protection / water / minerals / carbon dioxide ;\n© Cambridge University Press & Assessment 2025 Page 22 of 25\n\n8(c)(i) (photosystem) II / 2 / 680 ; 1\n\n8(c)(ii) A to B (occurs in very low light conditions) 4\nrespiration (rate) greater than photosynthesis (rate) ;\n(so) oxygen, consumed / not released ;\nafter C\nlight intensity not limiting ;\ncarbon dioxide concentration / temperature, is limiting ;\nQuestion Answer Marks", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p22.png", "../answer-assets/9700_s25_ms_42-p23.png" ] }, { "id": "9700-2025-mj-42-q09", "question_id": "9700-2025-mj-42-q09", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 9, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 ref. to quadrat of, known / same / standard, area / size ;\n2 ref. to setting out a grid ;\n3 random number generator (to produce coordinates) for quadrat placement ;\n4 use a key ;\n5 count number of species / numbers of individuals of each species / abundance / percentage cover / ACFOR / Braun-\nBlanquet ;\n6 ref. to large sample size / repeats ;\n7 (use results to calculate) Simpson’s Index of Biodiversity / species density ;\n© Cambridge University Press & Assessment 2025 Page 23 of 25\n\n9(b)(i) – 0.923 ;;; 3\nallow 2 marks if no minus\nallow 2 marks if not three decimal places\nallow 2 marks if incorrect value of n used\nif n is 10 answer = – 2.333\nif n is 120 answer = 0.998\n\n9(b)(ii) r  critical value 2\ns\nor\n0.923  0.504 ;\nnull hypothesis rejected as there is a, significant / strong / negative, correlation\nor\nnull hypothesis rejected as correlation not due to chance / probability that correlation due to chance is less than 5% ;\necf from 9(b)(i)\n© Cambridge University Press & Assessment 2025 Page 24 of 25", "source_pages": [ 23, 24 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p23.png", "../answer-assets/9700_s25_ms_42-p24.png" ] }, { "id": "9700-2025-mj-42-q10", "question_id": "9700-2025-mj-42-q10", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "10(a) any four from: 4\nduring – increase in lactate concentration\n1 (initially) lactate concentration low due to aerobic respiration ;\n2 no / less, oxygen available so (increase in) anaerobic respiration ;\n3 pyruvate, reduced / converted, to lactate ;\nafter – decrease in lactate concentration\n4 (more) oxygen available so aerobic respiration occurs ;\n5 lactate, oxidised / converted, to pyruvate ;\n6 idea that lactate is processed by liver ;\n7 AVP ; e.g. ref. to oxygen debt / EPOC\n\n10(b) any three from: 3\n1 (captive) breeding programs / described / frozen zoos ;\n2 marine reserves / protected areas ;\n3 ban on hunting / trade, (of seals) ;\n4 ref. to education / awareness ;\n5 research ;\n6 reduce, ocean / sea, pollution / described ;\n7 reduce fishing ;\n8 reduce climate change ;\n© Cambridge University Press & Assessment 2025 Page 25 of 25", "source_pages": [ 25 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_42.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_42-p25.png" ] }, { "id": "9700-2025-mj-43-q01", "question_id": "9700-2025-mj-43-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "1(a) A – GLUT / carrier ; I channel 3\nB – glycolysis ;\nC – intermembrane space ; A intermembranal R inner membrane\n\n1(b) any four from: 4\n1 (pyruvate) decarboxylation / decarboxylase / carbon dioxide released ;\n2 (pyruvate) dehydrogenation / dehydrogenase / oxidation ;\n3 formation of, acetyl group / acetate ;\n4 reduced NAD produced / described ;\n5 acetyl group / acetate, combines with coenzyme A\nor\nformation of acetyl CoA ;\n\n1(c) any three from: 3\n1 little / no, link reaction / Krebs cycle / oxidative phosphorylation ;\n2 ATP, mostly / only, produced by, glycolysis / process B / substrate-linked phosphorylation ;\n3 (so) less ATP produced ;\n4 anaerobic respiration / production of lactate ;\n© Cambridge University Press & Assessment 2025 Page 8 of 20", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p08.png" ] }, { "id": "9700-2025-mj-43-q02", "question_id": "9700-2025-mj-43-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 11, "status": "available", "reason": null, "text": "2(a)(i) any four from: 4\n1 antibiotic acts as selection pressure ;\n2 bacteria with antibiotic resistance (gene / allele) have selective advantage / selected for ; ora\n3 bacteria with antibiotic resistance (gene / allele), survive / reproduce ; ora\n4 pass on, gene / allele, (for antibiotic resistance)\nor\nincrease in allele frequency (for antibiotic resistance) ;\n5 ref. to plasmids ;\n6 (horizontal gene transfer) by, transduction / transformation / conjugation ;\n7 (horizontal gene transfer) gives rapid increase of resistant bacteria ;\n\n2(a)(ii) any two from: 2\n1 drug prevents attachment of mRNA to ribosome\nor\ndrug prevents attachment of tRNA to, amino acid / ribosome / mRNA\nor\ndrug binds to ribosome ;\n2 protein (coded for by antibiotic resistance gene) not made ;\n3 so antibiotic able to work ;\n© Cambridge University Press & Assessment 2025 Page 9 of 20\n\n2(b)(i) any three from: accept ora throughout 3\nnatural selection\n1 environment as selection pressure ; ora human acts as selection pressure\n2 random mating ; ora humans select organisms to breed\n3 takes more generations for effects to be seen / slower process / AW ;\n4 organisms not selected for desirable phenotypes ; ora humans select features\n5 can result in speciation ;\n6 does not decrease, genetic diversity / hybrid vigor ;\n7 inbreeding less likely to occur ;\n8 greater heterozygosity ;\n\n2(b)(ii) 1 offspring (from F1) will not be genetically similar / AW ; 2\n2 offspring (from F1) will produce variation in next crop / will not be true-breeding plants;\n© Cambridge University Press & Assessment 2025 Page 10 of 20", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p09.png", "../answer-assets/9700_s25_ms_43-p10.png" ] }, { "id": "9700-2025-mj-43-q03", "question_id": "9700-2025-mj-43-q03", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "3(a) 1 enzymes produced when, allolactose / lactose / substrate, is present 2\nor\nenzymes only produced when required ;\n2 genes not, expressed / switched on / transcribed, continuously\nor\ngenes, expressed / switched on / transcribed, when, allolactose / lactose / substrate, binds to repressor ;\nI inducer\n\n3(b) any seven from: 7\n1 lactose enters the bacterium ;\n2 lactose binds to the repressor ;\n3 causing a shape change ;\n4 the repressor detaches from the operator ;\n5 promoter unblocked / AW ;\n6 RNA polymerase binds to the promoter ;\n7 gene(s) transcribed ;\n8 β-galactosidase is made ;\n9 β-galactosidase breaks down lactose ;\ngalactosidase activity levels off as:\n10 β-galactosidase activity at maximum / galactosidase active sites full ;\n© Cambridge University Press & Assessment 2025 Page 11 of 20", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p11.png" ] }, { "id": "9700-2025-mj-43-q04", "question_id": "9700-2025-mj-43-q04", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 8, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 geographical, isolation / barrier (caused by the, river / canyon walls) ;\n2 no gene flow between (isolated ancestral) populations ;\n3 different, selection pressures / environment ;\n4 different / random / independent, mutations (in each population) ;\n5 different changes in allele frequencies / different gene pools / different alleles selected for ;\n6 populations have different, morphological / physiological / behavioral, features ;\n7 leads to, reproductive isolation / inability to interbreed (to produce fertile offspring) ;\n8 allopatric speciation ;\n\n4(b) any three from: 3\nDNA sequencing ora for fossils\n1 provides more information (about the whole organism) ;\n2 more precise / more accurate ;\n3 only a small sample of DNA is needed ;\n4 can give estimate of when species diverged/how closely related two organisms are / molecular clock can estimate time\nof divergence ;\n5 quantitative ;\n6 AVP ; e.g. idea of. avoids convergent evolution problems\n© Cambridge University Press & Assessment 2025 Page 12 of 20\n\n4(c) any one from: 1\nnot enough fossils ;\nsmall sample sizes ;\nDNA degrades over time ;\nthis depends on an estimated mutation rate ;\nQuestion Answer Marks", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p12.png", "../answer-assets/9700_s25_ms_43-p13.png" ] }, { "id": "9700-2025-mj-43-q05", "question_id": "9700-2025-mj-43-q05", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "5(a) any three from: 3\n1 cDNA has, no introns / only exons\nor\ngenomic DNA has introns (and exons) ;\n2 introns are non-coding sequences / exons are coding sequences ;\n3 bacteria cannot, remove introns / carry out splicing ;\n4 with cDNA, functional mRNA is made / translation occurs\nor\nwith genomic DNA, functional mRNA is not made / translation does not occur ;\n\n5(b)(i) bond together / anneal, with hydrogen bonds ; 2\nformation of phosphodiester bonds / joins sugar phosphate backbone ;\n\n5(b)(ii) 1 so RNA polymerase can bind ; 2\n2 so, transcription / gene expression, occurs ;\n© Cambridge University Press & Assessment 2025 Page 13 of 20\n\n5(c) any three from: 3\n1 marker gene is added to plasmid ;\n2 positioned downstream of promoter ;\n3 positioned alongside, GOI / insulin gene;\n4 when marker gene is expressed fluorescent proteins are made ;\n5 ref. to (fluorescent proteins) fluoresce / glow, with exposure to, UV / blue, light ;\n6 shows which, bacteria / cells, are transformed / AW ;\n\n5(d) any two from: 2\nadvantages of using yeast:\n1 easier / cheaper, to culture yeast cells ;\n2 more productive / higher productivity ;\n3 easier, to extract / processing / to purify, (insulin) ;\n4 yeast cell similar to β-cells / named example ; e.g. have Golgi apparatus\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p13.png", "../answer-assets/9700_s25_ms_43-p14.png" ] }, { "id": "9700-2025-mj-43-q06", "question_id": "9700-2025-mj-43-q06", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 12, "status": "available", "reason": null, "text": "6(a)(i) urea ; 1\n\n6(a)(ii) deamination / ornithine cycle / urea cycle / converts ammonia (to urea) ; 1\n\n6(a)(iii) liver ; 1\n© Cambridge University Press & Assessment 2025 Page 14 of 20\n\n6(b) any seven from: 7\n1 blood enters glomerulus via afferent arteriole ;\n2 afferent arteriole (lumen) diameter larger than efferent ;\n3 (so) high, blood / hydrostatic, pressure ;\n4 blood / hydrostatic, pressure greater than water potential gradient (between Bowman’s capsule and glomerulus) ;\n5 fluid forced through pores / fenestrations in (blood vessel) endothelium ;\n6 basement membrane acts as a filter ;\n7 stops, large proteins / blood cells / molecules larger than 68 000–70 000 RMM ;\n8 water / glucose / amino acids / urea / mineral ions, pass through ;\n9 slit pores between podocytes ;\n10 AVP ; e.g. GFR 125 cm–3 min–1\n\n6(c) any two from: 2\n1 collecting duct in medulla ;\n2 thicker medulla has lower water potential ;\n3 (so) more water reabsorbed ;\n4 AVP ; e.g. ref. to loop of Henle\n© Cambridge University Press & Assessment 2025 Page 15 of 20", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p14.png", "../answer-assets/9700_s25_ms_43-p15.png" ] }, { "id": "9700-2025-mj-43-q07", "question_id": "9700-2025-mj-43-q07", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "7(a)(i) DNA ; 2\nribosome ;\n\n7(a)(ii) thylakoid space ; 1\n\n7(b) xanthophyll ; 3\n3.4 ;\n0.92 ;\n\n7(c) any four from: 4\n1 absorbs light between 400 and 500 nm / peak at 450 nm ;\n2 accessory pigment ;\n3 absorbs light wavelengths not absorbed by, reaction centre / primary pigment / chlorophyll a ; A harvest\n4 so extends the range of wavelengths absorbed ;\n5 pass energy to, reaction centre / primary pigment / chlorophyll a ;\n6 idea improves efficiency of light-dependent stage ;\n© Cambridge University Press & Assessment 2025 Page 16 of 20", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p16.png" ] }, { "id": "9700-2025-mj-43-q08", "question_id": "9700-2025-mj-43-q08", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 7, "status": "available", "reason": null, "text": "8(a) 1 prevents illegal, trading / poaching / hunting ; 3\n2 trading requires permits / trading is regulated ;\n3 ref. to awareness / education ;\n\n8(b) any four from: 4\n1 multicellular ;\n2 eukaryote / eukaryotic / (cells), contain a nucleus ;\n3 specialised cells / tissues / organs ;\n4 heterotrophic (nutrition) / described ;\n5 nervous system ;\n6 (some cells have) cilia / flagella ;\n7 mobile / motile / locomotion ;\n© Cambridge University Press & Assessment 2025 Page 17 of 20", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p17.png" ] }, { "id": "9700-2025-mj-43-q09", "question_id": "9700-2025-mj-43-q09", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 13, "status": "available", "reason": null, "text": "9(a) any four from: 4\n1 use (named) sense organs to detect prey ;\n2 faster transmission of, impulses / signals ;\n3 (so) faster reaction to stimuli ;\n4 ref. to control centre / brain / CNS (decision making) ;\n5 faster response\nor\nref. reflexes ;\n6 (by) muscles ;\n\n9(b) (if a letter is used more than once, all must be correct) 3\ncorrect position of label and letter for:\nR ;\nS ;\nT ;\nS\nS\nR\nR T\n© Cambridge University Press & Assessment 2025 Page 18 of 20\n\n9(c)(i) any three from: 3\nincrease in curve\n1 cross bridges form / myosin heads bind to actin ;\n2 power stroke / actin filaments slide over myosin filaments ;\n3 bands get, smaller / shorter\nor\ndecrease in width of sarcomere ;\ndecrease in curve\n4 breaking of cross bridges / detachment of myosin heads from actin ;\n5 bands get, bigger / longer\nor\nincreases width of sarcomere ;\n\n9(c)(ii) increase 3\n1 calcium ions / Ca2+, released by sarcoplasmic reticulum ;\n2 calcium ions / Ca2+, bound to troponin ;\ndecrease\n3 calcium ions / Ca2+, pumped back into sarcoplasmic reticulum ;\n© Cambridge University Press & Assessment 2025 Page 19 of 20", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p18.png", "../answer-assets/9700_s25_ms_43-p19.png" ] }, { "id": "9700-2025-mj-43-q10", "question_id": "9700-2025-mj-43-q10", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 8, "status": "available", "reason": null, "text": "10(a) any three from: 3\n1 self-contained unit ;\n2 community of organisms ; A idea of several species\n3 biotic and abiotic factors / named ;\n4 ref. to interaction ;\n5 AVP ; e.g. flow of energy and cycling of minerals / nutrients\n\n10(b)(i) any three from: 3\n1 (frogs are) mobile ;\n2 marking, not harmful / cannot be removed ;\n3 (sufficient time for) marked individuals to mix with rest of population ;\n4 no, births / deaths\nor\nno, immigration / emigration / migration\nor\nconstant population size ;\n\n10(b)(ii) 69 ;; 2\nmust be a whole number, one mark only if not whole number\n27  33\n13\ncredit working if wrong answer\n© Cambridge University Press & Assessment 2025 Page 20 of 20", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_43-p20.png" ] }, { "id": "9700-2025-mj-44-q01", "question_id": "9700-2025-mj-44-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 1, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "1(a) any three from: 3\n1 osmoreceptors detect (decrease)\nor\nosmoreceptors, shrink / decrease in volume ;\n2 ref. to hypothalamus ;\n3 hypothalamus produces (more) ADH ;\nA neurosecretory cells produce ADH\nR secretion\n4 posterior pituitary releases (more) ADH (into blood) ;\nA secretes\nR produces\n\n1(b)(i) second(ary) messenger ; 1\n\n1(b)(ii) adds aquaporins into, cell surface / luminal, membrane ; 2\n(so) more permeable to water ;\n\n1(b)(iii) arrow from lumen into cell and arrow from cell into capillary 1\nor\none arrow from lumen through cell and into capillary ;\n© Cambridge University Press & Assessment 2025 Page 9 of 27\n\n1(c) any two from: 2\n1 no / less, water reabsorbed\nor\nno / less, water absorbed into, capillary / blood ;\nI tissue fluid\n2 water potential of blood, (remains) low / lower than set point ;\n3 large(r) volume of urine / dilute urine / low(er) concentration of urine ;\nI amount / more water excreted / more urine\n4 AVP ; e.g. feelings of thirst / dehydration / dizzy / fatigue /\nADH release continues / decreased blood volume\n© Cambridge University Press & Assessment 2025 Page 10 of 27", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p09.png", "../answer-assets/9700_s25_ms_44-p10.png" ] }, { "id": "9700-2025-mj-44-q02", "question_id": "9700-2025-mj-44-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 14, "status": "available", "reason": null, "text": "2(a) any two from: 4\ngene\n1 mutation of, HTT / huntingtin, gene ;\n2 ref. to dominant\nor\nonly one, mutant / AW, allele, needed\nor\nheterozygote will have disease ;\n3 ref. to (more) CAG repeats ;\nplus any three from:\nprotein\n4 non-functional / AW, huntingtin (protein) ;\nphenotype\n5 idea of cognitive / behavioural / personality / mood, changes ;\n6 coordination / movement, difficulties ;\n\n2(b) 1 only males get the disease / females do not get the disease ; 3\n2 only males have a Y chromosome / males are XY\nor\nfemales, do not have a Y chromosome / only have (two) X chromosomes ;\n3 all, sons / male offspring, of affected, males / fathers, have the disease\nor\nall sons will not have the disease if father does not have the disease ;\n© Cambridge University Press & Assessment 2025 Page 11 of 27\n\n2(c) parental genotypes XAXa x XaY 4\nand\ngametes XA Xa and Xa Y ;\ncorrect offspring genotypes\nXA Xa\nXa XA Xa XaXa\naffected / AW healthy / normal,\nfemale female\nY XAY XaY\naffected / AW healthy / normal,\nmale male ;\nphenotypes linked to genotypes (see Punnet Square) ;\nratio of offspring phenotypes: 1 : 1 : 1 : 1 ;\n© Cambridge University Press & Assessment 2025 Page 12 of 27\n\n2(d) any three from: 3\n1 no repressor produced / no repressor binds to operator\nor\naltered / faulty, repressor produced ;\n2 (so) structural genes are, transcribed / expressed / switched on ;\n3 (structural gene) proteins / enzymes, produced ;\n4 (these) proteins / enzyme, damage cell / changes metabolism / causes disease ;\n5 altered repressor, binds more tightly / AW, to operator ;\n6 (so) structural genes, not transcribed / not expressed / switched off ;\n7 (structural gene) proteins / enzymes, not produced ;\n8 (so) lack of, protein / enzyme, causes, damage to cell / change to metabolism / disease ;\n© Cambridge University Press & Assessment 2025 Page 13 of 27", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p11.png", "../answer-assets/9700_s25_ms_44-p12.png", "../answer-assets/9700_s25_ms_44-p13.png" ] }, { "id": "9700-2025-mj-44-q03", "question_id": "9700-2025-mj-44-q03", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 3, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 11, "status": "available", "reason": null, "text": "3(a)(i) any two from: 3\nq2 = 0.068 ;\nq = 0.260768 ;\np = 0.739232 ;\n2pq = 0.385536 ;\nand\n38.6 / 39 (%) ;\n\n3(a)(ii) any two from: 2\n1 migration / AW, occurs\nor\npopulation is not isolated\nor\ngene flow, in / out, of population ;\n2 no random mating ;\n3 ref. to mutations ;\n4 ref. to selection ;\n© Cambridge University Press & Assessment 2025 Page 14 of 27\n\n3(b) any three from: 3\n1 inbreeding ;\n2 low genetic diversity / small gene pool ;\n3 founder effect / bottleneck ;\n4 genetic drift ;\n5 tailless (cat) has a selective advantage / is selected for ; ora\n6 tailless allele is dominant ;\n7 allele frequency for tailless (phenotype) increases ;\n\n3(c) any three from: 3\n1 mutation results in (black) spots (phenotype / allele) ;\n2 selection pressure is, ability to catch prey / AW\nor\nindividuals with spots, have a selective advantage / are selected for ; ora\n3 spotted (cheetahs), survive / reproduce ; ora\n4 spotted, allele / mutation, passed on (to offspring) ;\n5 spotted, allele / mutation, frequency increased ;\n© Cambridge University Press & Assessment 2025 Page 15 of 27", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p14.png", "../answer-assets/9700_s25_ms_44-p15.png" ] }, { "id": "9700-2025-mj-44-q04", "question_id": "9700-2025-mj-44-q04", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 4, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "4(a) 4\nKingdom species may be species may have species may show\nunicellular cell walls autotrophic nutrition\nAnimalia no no no ;\nFungi yes yes no ;\nPlantae no yes yes ;\nProtoctista yes yes yes ;\none mark per correct row\n\n4(b) A = metaphase I ; 3\nB = telophase I ;\nA anaphase I\nC = anaphase II ;\nA telophase II\n© Cambridge University Press & Assessment 2025 Page 16 of 27\n\n4(c) 1. Bacteria and Archaea ; 3\nplus any two from:\nBacteria Archaea\n2 cell wall peptidoglycan no peptidoglycan ;\n3 cell membrane ester-linked ether-linked ;\nlipids / unbranched lipids / branched\nhydrocarbon chains hydrocarbon chains\n4 spores form spores do not form spores ;\n5 DNA associated no histones have histones ;\nproteins\n6 ribosomal RNA / rRNA are different ;\n(base sequences)\nor\nribosomes (structure)\n\n4(d) any two from: 2\n1 RNA or DNA ;\n2 single-stranded or double-stranded (nucleic acid) ;\n3 AVP ; e.g. how mRNA is produced / enveloped or non-enveloped / linear or circular / which diseases they cause / capsid\nshape\n© Cambridge University Press & Assessment 2025 Page 17 of 27", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p16.png", "../answer-assets/9700_s25_ms_44-p17.png" ] }, { "id": "9700-2025-mj-44-q05", "question_id": "9700-2025-mj-44-q05", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 11, "status": "available", "reason": null, "text": "5(a) any five from: 5\nAllow any temperature within the ranges given\n1 denaturation at 90–98 °C ;\n2 breaks hydrogen bonds (in DNA) to, produce single strands / separate the (two) strands ;\n3 annealing at 50–65 °C ;\n4 (so that) primers, anneal / bind, (ss)DNA / complementary bases ;\n5 (to provide) binding site / starting point (for Taq polymerase) ;\n6 extension or elongation at 65–75 °C ;\n7 Taq polymerase joins, (free) nucleotides / dNTPs, to (single) strands\nor\nTaq polymerase synthesises, complementary / new, strand (of DNA) ;\n© Cambridge University Press & Assessment 2025 Page 18 of 27\n\n5(b)(i) any four from: 4\nbacteria = E.coli and virus = herpes simplex throughout\n1 extract / isolate / cut, DNA (sequences) using restriction enzyme\nor\nmake DNA (sequences) using mRNA using reverse transcriptase\nor\nmake DNA (sequences) using nucleotides ;\n2 use DNA ligase to join together (the two sequences of) DNA (of bacteria and virus) ;\n3 add promoter ;\n4 add, tTav / recombinant DNA / gene, to, vector / virus / liposome ;\n5 infect egg with virus\nor\n(micro)injection into egg ;\nA gene gun / DNA gun\n6 virus adds, tTav / recombinant DNA / gene, into genome (of egg / A. stephensi) ;\n\n5(b)(ii) any one from: 1\n1 idea that prevents, transcription factor, functioning / binding to promoter ;\nR repressor proteins / operator\n2 stops RNA polymerase from binding to, DNA / promoter ;\n\n5(b)(iii) (genetically modified males) develop into adults / survive beyond the larval stage ; 1\n© Cambridge University Press & Assessment 2025 Page 19 of 27", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p18.png", "../answer-assets/9700_s25_ms_44-p19.png" ] }, { "id": "9700-2025-mj-44-q06", "question_id": "9700-2025-mj-44-q06", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 6, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 7, "status": "available", "reason": null, "text": "6(a) any three from: 3\n1 self-contained / functional / specific (unit) ;\n2 community / all species / all populations ;\n3 ref. to interactions ;\n4 abiotic / physical / non-living, and, biotic / biological / living, factors / environment ;\n5 idea that linked by, energy flow / mineral cycling / food webs / food chains / nutrient cycle ;\n\n6(b) if individuals can breed to produce fertile offspring ; 1\n\n6(c) any three from: 3\n1 allopatric speciation ;\n2 geographical, isolation / barrier / separation ;\n3 (so) no gene flow (between populations) ;\n4 (populations have) different, mutations / advantageous alleles / alleles increase in frequency ;\n5 (populations have) different, selection pressures / environments ;\n© Cambridge University Press & Assessment 2025 Page 20 of 27", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p20.png" ] }, { "id": "9700-2025-mj-44-q07", "question_id": "9700-2025-mj-44-q07", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 7, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 10, "status": "available", "reason": null, "text": "7(a)(i) oxygenated 3\n1 percentage (of root tissue as aerenchyma), remains low ;\nany two from:\ndeoxygenated\n2 percentage (of root tissue as aerenchyma), increases gradually / small increase, initially / until 24 hours ;\n3 percentage (of root tissue as aerenchyma), larger / steeper / more rapid, increase after 24 hours ;\n4 percentage (of root tissue as aerenchyma), stays the same / is constant / plateaus / levels off / reaches maximum, at,\nthe end / 48 hours ;\n5 data quote ; two times and two percentages with units\ntime / h percentage of root tissue as aerenchyma when\ndeoxygenated\n0 0.1 – 0.3\n12 0.5 – 0.6\n24 0.8\n36 2.5 – 2.6\n48 6.5 – 6.6\n60 6.5 – 6.6\n\n7(a)(ii) 1 (aerenchyma is a tissue) with many / more / large, air spaces ; 3\n2 (so) oxygen, diffuses / moves, (from the aerial parts) to root (cells) / lower parts of the plant / AW ;\n3 (for) aerobic respiration ;\n© Cambridge University Press & Assessment 2025 Page 21 of 27\n\n7(b) any four from: 4\n1 fast(er), stem / internode, growth ;\n2 (so) leaves / flowers, above water level ;\n3 (so) photosynthesis / gas exchange / reproduction, can occur ;\n4 (root cells) tolerant to (increased concentration of) ethanol\nor\n(root cells) have more ethanol dehydrogenase ;\n5 so, anaerobic respiration / ethanol fermentation, can occur ;\n6 AVP ; e.g. leaves have ridges\n7 AVP ; e.g. to trap air (so oxygen can be taken in by plant)\n© Cambridge University Press & Assessment 2025 Page 22 of 27", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p21.png", "../answer-assets/9700_s25_ms_44-p22.png" ] }, { "id": "9700-2025-mj-44-q08", "question_id": "9700-2025-mj-44-q08", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "8(a) P to light area ; A on Z line 3\nQ to medium area ; A on M line\nR to darker area ;\nP R\nQ\nP in I band\nQ in H\nlightest\nzone\nR either side of H zone in A\nband – darkest – overlap\n© Cambridge University Press & Assessment 2025 Page 23 of 27\n\n8(b) any four from: 4\n1 (at rest) tropomyosin, covers / AW, the binding sites on actin ;\nR active sites\n2 Ca2+ binds to troponin ;\n3 troponin changes shape ;\n4 (causing) tropomyosin to move ;\n5 (so) exposes binding site ;\n6 (so) myosin head, binds (to binding sites) / forms crossbridge ;\n\n8(c) any two from: 2\n1 no / less, Ca2+ ;\n2 no / less, ATP ;\n3 no / less, glucose / glycogen ;\n4 no / less, oxygen ;\n5 build-up / presence of, lactate / lactic acid ;\n6 AVP ; e.g. no / less, creatine phosphate\n© Cambridge University Press & Assessment 2025 Page 24 of 27", "source_pages": [ 23, 24 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p23.png", "../answer-assets/9700_s25_ms_44-p24.png" ] }, { "id": "9700-2025-mj-44-q09", "question_id": "9700-2025-mj-44-q09", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "9(a) any seven from: 7\n1 light absorbed by, chlorophyll / pigments (in PI and PII)\nor\nphotoactivation of chlorophyll (in PI and PII) ;\n2 electrons, emitted (to higher energy levels) / excited, in both photosystems ;\n3 electrons pass along, electron transport chain / ETC / electron carriers ;\n4 detail ; e.g. electrons releasing energy to pump H+ into thylakoid, space / lumen\nref. to proton gradient set up\nprotons diffusing through ATP synthase\n5 ATP synthesised from ADP and P / ref. to chemiosmosis ;\ni\n6 (PII contains) oxygen-evolving complex ;\nA water-splitting enzyme\n7 ref. to photolysis (of water) ;\n8 oxygen and hydrogen ions and electrons produced ;\nA H O 2e- + 2H+ + ½O\n2 2\n9 electrons emitted from PI replaced by electrons from PII\nor\nelectrons emitted from PII replaced by electrons from photolysis (of water) ;\n10 electrons (from PI) combine with H+ to form reduced NADP\nor\nelectrons (from PI) combine with NADP to form reduced NADP\nor\nelectrons (from PI) combine with H+ to form hydrogen that reduces NADP ;\nR H+ reduce NADP\n© Cambridge University Press & Assessment 2025 Page 25 of 27\n\n9(b) 1 increase in light intensity increases rate of photosynthesis until it levels off (at higher light intensities) ; 3\n2 (increase means) more, light dependent reaction / cyclic photophosphorylation / non-cyclic\nphotophosphorylation / photoactivation ;\n3 (as rate levels off) carbon dioxide concentration / temperature, becomes limiting factor\nor\nlight intensity is no longer a limiting factor ;\nQuestion Answer Marks", "source_pages": [ 25, 26 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p25.png", "../answer-assets/9700_s25_ms_44-p26.png" ] }, { "id": "9700-2025-mj-44-q10", "question_id": "9700-2025-mj-44-q10", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 10, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "10(a)(i) molecules / moles / volume, carbon dioxide produced 1\nmolecules / moles / volume, oxygen taken in ;\n\n10(a)(ii) 25 ; 1\n\n10(a)(iii) 0.72 ; 1\nA ecf 18 divided by their answer to 10(a)(ii)\n© Cambridge University Press & Assessment 2025 Page 26 of 27\n\n10(b) any four from: 4\n1 RQ (initially) at 1.0 as, carbohydrates / (named) sugar, respired / metabolised ;\n2 RQ decreases (over time) as, carbohydrates / (named) sugar, running out / used up ;\n3 RQ decreases (over time) as a mixture of carbohydrate and lipid respired ;\nI proteins\n4 RQ at, 0.65 / 0.7, as, fatty acids / fats / lipids, respired (as main respiratory substrate)\nor\nfrom 120 min onwards, fatty acids / fats / lipids, respired (as main respiratory substrate) ;\n5 data quote ; RQ of 1.0 at 40 min plus any RQ value at any other time\nTime after RQ ratio\nfeeding / min\n40 1.0\n80 0.75\n120 0.7\n160 0.65\n200 0.7\n240 0.7\n© Cambridge University Press & Assessment 2025 Page 27 of 27", "source_pages": [ 26, 27 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_44.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_44-p26.png", "../answer-assets/9700_s25_ms_44-p27.png" ] }, { "id": "9700-2025-mj-51-q01", "question_id": "9700-2025-mj-51-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 17, "status": "available", "reason": null, "text": "1(a)(i) any one from: 1\n1 calibrate colorimeter ;\n2 use, a blank / AW, to set (colorimeter absorbance) to zero ;\n\n1(a)(ii) 1 rate of change in absorbance at pH 2.0 = 3\n0.0036 / 3.6  10–3 ;\n2 working:\n(0.52–0.23) / (120–40)\nor\n0.29 / 80 ;\n3 units:\nau s-1 ;\n© Cambridge University Press & Assessment 2025 Page 8 of 14\n\n1(b)(i) any seven from: 7\n1 prepare (at least) five solutions with stated pH values between pH 0 and 6.5 ;\n2 same / stated, volume / concentration, of pepsin (solution) used ;\n3 method to maintain a, constant / stated, temperature ;\n4 equilibrate / AW, all (pepsin, pH / buffer / albumen) solutions separately (before mixing) ;\n5 method to mix, pepsin and pH (buffer) albumen (solutions, before adding to colorimeter) ;\n6 at each pH, measure / note / record / AW, absorbance at, set / stated, time intervals ;\n7 use at least three replicates for each pH and calculate a mean rate (of change in absorbance / of protein hydrolysis, for\neach pH) ;\n8 method to identify the optimum pH ;\n9 idea that repeat experiment with smaller pH intervals around the optimum pH ;\n10 safety comment with named hazard and risk and precaution ;\nhazard risk precaution\nalbumen / eggs allergy / irritant gloves / goggles / mask / PPE\npH buffer irritant / corrosive (at pH 0, 1, 2) gloves / goggles / mask / PPE\npepsin allergy / irritant gloves / goggles / mask / PPE\n© Cambridge University Press & Assessment 2025 Page 9 of 14\n\n1(b)(ii) 1 correct y-axis label ; e.g. rate of protein hydrolysis / aus-1 2\n2 appropriately shaped line ;\n© Cambridge University Press & Assessment 2025 Page 10 of 14\n\n1(c)(i) any two from: 2\n1 test condition 2, decreases / hydrolyses / AW, CA3 and Sep70 ;\n2 idea that acid / pH 4.0, with no active pepsin, does not change CA3 and Sep70 ;\n3 (mass / size / AW of) CA3 is smaller than Sep70 ; ora\n\n1(c)(ii) any two from: 2\n1 idea that pepsin only causes damage (to the laryngeal epithelium) if (hydrochloric) acid / pH 4.0, is also present ;\n2 investigation, only carried out once / was not repeated ;\n3 idea that no information on species of mammal used (in investigation)\nor\nidea that investigation, not carried out in a person / carried out in a laboratory ;\n4 idea that a reduction in quantity of Sep70 and CA3 may not cause damage to the laryngeal epithelium ;\n© Cambridge University Press & Assessment 2025 Page 11 of 14", "source_pages": [ 8, 9, 10, 11 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_51-p08.png", "../answer-assets/9700_s25_ms_51-p09.png", "../answer-assets/9700_s25_ms_51-p10.png", "../answer-assets/9700_s25_ms_51-p11.png" ] }, { "id": "9700-2025-mj-51-q02", "question_id": "9700-2025-mj-51-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) number of insect attraction events (in 6 hours) ; 1\n\n2(a)(ii) any two from: 2\n1 size / length / AW (of model / body / legs) ;\n2 shape / AW (of model) ;\n3 material / AW (of models) ;\n4 thickness / weight / mass / density / AW (of models) ;\n5 yellow, colour / shade / tone / pigment / AW (of models) ;\n6 light, absorption / reflection / AW (of models)\n7 size of spots (on model A and B) ;\n8 (models are) odourless / AW ;\n\n2(a)(iii) (measure insect attraction rate of) web with no model ; 1\n© Cambridge University Press & Assessment 2025 Page 12 of 14\n\n2(b)(i) any four from: 4\neffect of colour and pattern:\n1 idea that yellow colour (models A, C and D), have high insect attraction rates ;\n2 idea that pattern (of spots) is less important than colour (for attracting insects) ; ora\nusing information from Fig. 2.2:\n3 idea that, (standard) error bars for yellow (colour, models A, C, D) and not yellow (colour, models B, E), do not overlap,\n(therefore insect attraction rate may be) significantly different ;\n4 idea that, (standard) error bars for models A, C, and D overlap, (therefore insect attraction rate) is not significantly\ndifferent (for yellow models with different patterns) ;\nor\nidea that, (standard) error bars for models B, and E overlap, therefore insect attraction rate is not significantly different\n(for black models with no yellow colour) ;\n5 data quote, with units, to support ;\n\n2(b)(ii) there is no difference between, the (mean) insect attraction rates, of the models ; 1\n\n2(b)(iii) any two from: 2\n1 data is continuous ;\n2 comparing (two) means ;\n3 fewer than 30 values ;\n4 data is (from populations that are) normally distributed ;\n© Cambridge University Press & Assessment 2025 Page 13 of 14\n\n2(c) any two from: 2\n1 do investigation in, more than one, forest / geographical area / AW ;\n2 idea of do investigation, at different times of the day / AW ;\n3 do investigation in, more than one, month / season / year ;\n4 idea that only count insects that touch the, model / web ;\n5 use (more) models with different, colours / patterns\nor\nuse 3–dimensional model (instead of, flat / 2–dimensional, model) ;\n6 idea of (video) living spider on web ;\n© Cambridge University Press & Assessment 2025 Page 14 of 14", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_51-p12.png", "../answer-assets/9700_s25_ms_51-p13.png", "../answer-assets/9700_s25_ms_51-p14.png" ] }, { "id": "9700-2025-mj-52-q01", "question_id": "9700-2025-mj-52-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 mass of (mung bean) seedlings ;\n2 age / variety / type / cultivar (of mung bean) seedlings ;\n3 grinding time (using pestle and mortar) ;\n4 speed of centrifuge / time in centrifuge ;\n\n1(b)(i) explanation 2\nidea of the temperature (of, solutions / reactants) will not have reached 30 ºC / AW\nor\nthe rate of (enzyme)reaction, will change / not be constant / AW\nor\nreaction will start before reaching 30 ºC / AW ;\nmodification\nequilibrate / AW, phosphatase/enzyme/extract and PPP/substrate, separately\nor\nequilibrate / AW , phosphatase / enzyme / extract and PPP / substrate before mixing ;\n\n1(b)(ii) (sodium carbonate solution) denatures, the enzyme / phosphatase ; 1\n© Cambridge University Press & Assessment 2025 Page 8 of 13\n\n1(c) 1 five stated concentrations between 2 % and 0 % and units, % / percentage ; 2\n2 correct method for dilution shown for two intermediates ;\nconcentrations % 2 % stock / distilled water / cm3\nphenolphthalein /\ncm3\n2.0 50 0\n1.6 40 10\n1.5 37.5 12.5\n1.2 30 20\n1.0 25 25\n0.8 20 30\n0.5 12.5 37.5\n0.4 10 40\n0.25 6.25 43.75\n0.0 0 50\n\n1(d) 1 absorbance / AW, for the dilutions and extract / reaction mixture ; 2\n2 use the calibration, curve / graph (to determine phenolphthalein / extract concentration) ;\n© Cambridge University Press & Assessment 2025 Page 9 of 13\n\n1(e) any six from: 6\n1 prepare five solutions with stated pH values up to pH 7 ;\n2 equilibrate / AW, PPP / substrate, and, phosphatase / enzyme / extract, and buffer solutions, separately / before\nmixing ;\n3 mix buffered, PPP / substrate, with, extract / enzyme solution ;\n4 calibrate colorimeter\nor\nuse a blank / AW, to, set colorimeter (absorbance) to zero / reset colorimeter ;\n5 at each pH, stop the reaction / AW after a set time and, measure / note / record, absorbance ;\n6 suitable method to identify the optimum pH ;\n7 repeat experiment with smaller pH intervals around, the optimum pH / values with the highest\nabsorbance / concentration (of phenolphthalein) ;\n8 repeat experiment at least twice and calculate the mean (absorbance), for each pH / their means ;\n9 named hazard and risk and precaution ;\n© Cambridge University Press & Assessment 2025 Page 10 of 13\n\n1(e)\nhazard risk precaution\nphosphatase enzyme / mung allergy / irritant gloves / eye protection / PPE\nbean / extract\nphenolphthalein phosphate (PPP)\nsodium carbonate\npH buffer irritant pH 3–7 gloves / eye protection / PPE\nor\ncorrosive below pH 4\nphenolphthalein toxic / irritant / allergy gloves / eye protection / PPE\nflammable keep away from naked flame\n\n1(f)(i) point 6 on top line is circled ; 2\nhigher than, the V / 0.018 (mmoldm–3s–1) / the plateau ;\nmax\n\n1(f)(ii) (K withno inhibitor) 0.075 1\nm\nand\n(K with inhibitor) 0.43 / 0.425\nm\nand\nmmoldm–3 ;\n\n1(f)(iii) 1 working 2\ndifference divided by K with no inhibitor (100)\nm\n(0.425 – 0.075) / 0.075 (100) ;\n2 correct answer from working in mp1 ;\n© Cambridge University Press & Assessment 2025 Page 11 of 13", "source_pages": [ 8, 9, 10, 11 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_52-p08.png", "../answer-assets/9700_s25_ms_52-p09.png", "../answer-assets/9700_s25_ms_52-p10.png", "../answer-assets/9700_s25_ms_52-p11.png" ] }, { "id": "9700-2025-mj-52-q02", "question_id": "9700-2025-mj-52-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a) any two from: 2\n1 (same) time of the year\nor\n(same) seasons\nor\n(same) months ;\n2 (same) depth of, water / sea / sponge / (sea)bed / water pressure ;\n3 (same) orientation of transect ;\n\n2(b) 23 or 24 ; 2\ncorrect working ;\n\n2(c)(i) 1 any use of correct data to qualify a statement ; 3\nsupporting the conclusion ‘human activity equals lower diversity’\n2 station A has highest, index / diversity\nor\nstation G / thermal power station, has lowest index\nor\nnatural habitat / A, B, L, have a higher, index / diversity ;\nnot supporting the conclusion ‘human activity does not equal lower diversity’\n3 housing / D and A, have a similar index\nor\nD / housing, has a higher index / (diversity) value than, B / L\nor\nJ and K which have the same human activity have different, beta diversity indices / diversity\nor\nidea that the measure of diversity used just counts number of species and not number of individuals\nor\ndid not, use / calculate, Simpson’s diversity index ;\n© Cambridge University Press & Assessment 2025 Page 12 of 13\n\n2(c)(ii) answer must be in terms of the diversity of the sponges not diversity index (data) or beta diversity 3\nA ‘it’ for ‘species diversity’\nI biodiversity\n1 correct index data quoted to support conclusion about species diversity ;\nany two from mp2–6:\ndiversity in different locations in the bay:\n2 idea that (stations A, B, L) closest to open ocean / at the edges of the bay, have higher diversity\nor\nidea that (stations E, F, G, H, I, J) furthest from open ocean / within the bay, have lower diversity\nor\nin the (Algeciras) Bay the diversity is lower than the marine habitat / ora ;\ndiversity in industrial areas: (E,G, H, I)\n3 idea that overall industries / industrial activity, results in lower diversity ;\ndiversity in tourist areas (C, F, J, K)\n4 idea that tourism results in varied impact (on diversity) and qualified with suitable examples ;\n5 other (stated) factor affects diversity illustrated with a suitable station ;\n6 impact of, housing / D, on diversity is, similar to natural habitats / less than other stations with human activity ;\n© Cambridge University Press & Assessment 2025 Page 13 of 13", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_52-p12.png", "../answer-assets/9700_s25_ms_52-p13.png" ] }, { "id": "9700-2025-mj-53-q01", "question_id": "9700-2025-mj-53-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "1(a)(i) hazard and risk and precaution ; 1\nhazard risk precaution\nchemical / anaesthetic toxic / allergy / irritant use, gloves / goggles / mask / PPE / use\nfume cupboard\nDrosophila / fruit flies allergy / use gloves / goggles / mask / PPE\n(spread of) pathogens / biohazard\nagar jelly / specimen tube, allergy / biohazard / pathogens use gloves / goggles / mask / PPE /\ncontaining food aseptic technique\n\n1(a)(ii) any seven from: 7\n1 (to produce heterozygotes)\n(breed) brown-eyed /AAdd, females with, scarlet-eyed / aaDD, males\nor\n(breed) scarlet-eyed / aaDD, females with, brown-eyed / AAdd, males ;\n2 method to maintain a, constant / stated, temperature ;\n3 idea of remove parent (fruit flies) from their offspring, before they are adults / before day 10 / before eggs hatch ;\n4 put (anaesthetised), double heterozygotes / offspring from first cross, into (new specimen) tube ;\n5 (cross double heterozygotes to give) a large number of offspring ;\n6 use, stated / same / recommended / correct, dose / volume / concentration, (of chemical / anaesthetic) ;\n7 identify, phenotype / eye colour, using, microscope / magnifying glass / hand lens ;\n8 count / record, the number of flies of each, phenotype / eye colour ;\n9 idea of method to prevent double counting (of flies) ;\n© Cambridge University Press & Assessment 2025 Page 8 of 10\n\n1(a)(iii) 9 : 3 : 3 : 1 ; 2\nred : brown : scarlet : white ;\n\n1(b) any three from: 3\n1 critical value (at degrees of freedom = 3 and p = 0.05) is 7.815 ;\n2 calculated (χ2) value / 4.798, is less than, critical value / 7.815 ;\n3 null hypothesis is accepted (at p = 0.05) ;\n4 there is no significant difference (at p = 0.05) ;", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_53-p08.png", "../answer-assets/9700_s25_ms_53-p09.png" ] }, { "id": "9700-2025-mj-53-q02", "question_id": "9700-2025-mj-53-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 17, "status": "available", "reason": null, "text": "2(a) type of treatment (solution) ; 1\n\n2(b) any two from: 2\n1 volume of, treatment / EchAMP / bacitracin, solution ;\n2 concentration of, EchAMP / bacitracin, solution ;\n3 concentration / volume , of fluorescence (chemical) ;\n\n2(c)(i) (to) compare (the effect of EchAMP and) no EchAMP on, bacterial / E. coli (population), growth ; 1\n\n2(c)(ii) (to) compare (the effect of EchAMP to) bacitracin / antibiotic (on bacterial / E. coli (population), growth) ; 1\n\n2(d)(i) 1 axis labels with units on correct axes and completed key ; 2\n2 three correct data points plotted at 7 hours, with data points joined to the correct values at 6 hours ;\n© Cambridge University Press & Assessment 2025 Page 9 of 10\n\n2(d)(ii) any two from: 2\n1 bacitracin reduces (population growth of E. coli) more than EchAMP (after 6 hours / at 7 hours) ; ora\n2 no difference (in effect on E. coli) between 0 and 6 hours ;\n3 bacitracin and EchAMP reduce (population growth of E. coli) more than the negative control, after 3 hours / at\n6 hours / at 7 hours ;\n\n2(e)(i) there is no difference between the (mean) fluorescence (emitted by E. coli after seven hours when exposed to), the 1\nnegative control and EchAMP ;\n\n2(e)(ii) 1 correct working ; 3\n2 (t =) 9.37 when rounded to 3 significant figures ;\n3 (t =) 9.370 ; must be 4 significant figures\n\n2(e)(iii) any four from: 4\n1 idea that experiment is, not carried out in a person / carried out in a laboratory ;\n2 idea that experiment, only used E. coli / did not use other bacteria ;\n3 EchAMP may kill beneficial bacteria (in the digestive system) ;\n4 EchAMP might not be as effective as other, treatments / antibiotics ;\n5 EchAMP could, cause side effects / be toxic / AW, in humans\nor\nexperiment only carried out for 7 hours / no information about longer term effects ;\n6 EchAMP is a protein and would be digested (by enzymes in the digestive system) ;\n7 idea that the EchAMP did not kill all of the E. coli ;\n© Cambridge University Press & Assessment 2025 Page 10 of 10", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_53-p09.png", "../answer-assets/9700_s25_ms_53-p10.png" ] }, { "id": "9700-2025-mj-54-q01", "question_id": "9700-2025-mj-54-q01", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 21, "status": "available", "reason": null, "text": "1(a)(i) 1 distilled / deionised / pure / AW, water (as diluent) ; 2\n2 (use) 0.264g ABA and (dissolve in) 1 dm3 water ;\n\n1(a)(ii) 1 add, 10 cm3 of, stock solution / 1  10–3 (mol dm–3 ABA), to 90 cm3 (distilled) water (to make 1  10-4 mol dm–3 ABA) ; 2\n2 description, of one correct subsequent step of the serial dilution ;\n\n1(b)(i) independent variable: 2\nconcentration of ABA ;\ndependent variable:\nnumber of grains germinated\nor\nlength of shoot ;\n© Cambridge University Press & Assessment 2025 Page 9 of 14\n\n1(b)(ii) any five from: 5\n1 (use of a control for one group of 50 grains) replace the ABA solution with, distilled / deionised / pure / AW, water ;\n2 ref. to (placing wheat grains in a container with) soil / paper / AW ;\n3 carry out experiment in the dark ;\n4 method to maintain a, constant / stated, temperature (for germination) ;\n5 ref. to adding the, same / stated, volume / mass, of water (to container of wheat grains) ;\n6 for each ABA concentration, count / record / AW, the number of (wheat) grains that have germinated, after a,\nsame / stated, time\nor\nfor each ABA concentration, measure / record / AW, the length of the shoot, after a, same / stated, time ;\n7 safety comment with hazard and risk and precaution ;\nhazard risk precaution\nwheat grains irritant / allergy gloves / mask / PPE\nABA / GA irritant / allergy / toxic gloves / mask / PPE\nsoil biohazard / pathogens / gloves / mask / PPE\nallergy / irritant\n\n1(c)(i) number of germinated grains, divided by the, total number of grains, x 100 ; 1\n© Cambridge University Press & Assessment 2025 Page 10 of 14\n\n1(c)(ii) 1 axes correctly orientated with labels and units ; 3\n2 correct values on x-axis ;\n3 line shows percentage germination decreases as ABA concentration increases ;\n\n1(d)(i) any two from: 2\n1 idea of smaller standard error (SE) shows that (the mean is) more reliable ; ora\n2 idea of smaller SE shows that (calculated / sample) mean is closer to the, true / actual, mean ; ora\n3 suitable example from Table 1.1 ;\n4 correct ref. to overlap of SE from Table 1.1 ;\nfor example:\nidea of, SE for 1  10–7 ABA concentration and 1  10–6 ABA concentration do not overlap, (therefore mean shoot length\nmay be) significantly different\nor\nidea of, SE for 1  10–6 ABA concentration and 1  10–4 ABA concentration overlap, (therefore mean shoot length) is\nnot significantly different\n\n1(d)(ii) there is no difference, in the (mean) shoot length (of the seedlings grown from wheat grains with), no GA (treatment) and (1 1\n 10-5 mol dm–3) GA (treatment) ;\n© Cambridge University Press & Assessment 2025 Page 11 of 14\n\n1(d)(iii) 1 use 38 degrees of freedom ; 3\n2 compare (calculated) t-value with, critical (t-) value at, (p) = 0.05 / 5% ;\n3 (if calculated) t-value is higher (than the critical t-value then)\nand\nreject null hypothesis / there is a significant difference ; ora\nQuestion Answer Marks", "source_pages": [ 9, 10, 11, 12 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_54.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_54-p09.png", "../answer-assets/9700_s25_ms_54-p10.png", "../answer-assets/9700_s25_ms_54-p11.png", "../answer-assets/9700_s25_ms_54-p12.png" ] }, { "id": "9700-2025-mj-54-q02", "question_id": "9700-2025-mj-54-q02", "subject": "9700", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "2(a) any one from: 1\n1 idea that (cold buffer) prevents, (mitochondrial) enzymes / proteins , denaturing ;\n2 idea that (cold temperature) prevents damage to mitochondria, by enzymes ;\n3 idea that (buffer) prevents (osmotic) lysis of mitochondria ;\n\n2(b)(i) 49.50 ; 1\n© Cambridge University Press & Assessment 2025 Page 12 of 14\n\n2(b)(ii) correct identification of anomalous results ;; 2\nrate of oxygen consumption\ntrial 1 trial 2 trail 3 trial 4 mean\nmitochondria alone 0.03 0.02 0.03 0.01 0.02\nsuccinate added 50.22 49.10 48.53 50.15 49.50\nADP and succinate 139.23 170.10 142.67 138.10 147.53\nadded\nADP, succinate and 0.00 0.10 0.00 0.01 0.03\ncyanide added\n\n2(b)(iii) 1 do not include, anomalies and calculate (a more accurate) mean ; 2\n2 calculate, standard deviation / standard error / 95% confidence limits (for each trial) ;\n© Cambridge University Press & Assessment 2025 Page 13 of 14\n\n2(c) any three from: 3\n1 in mitochondria (alone):\noxygen concentration does not change\nor\ndo not use oxygen\nor\nrate of oxygen consumption is very low ;\n2 adding succinate (and no ADP) increases the rate of, aerobic respiration / Krebs cycle / oxidative phosphorylation ;\n3 adding succinate and ADP, gives a larger increase in the rate of, aerobic respiration / Krebs cycle / oxidative\nphosphorylation ;\n4 oxygen acts as the final electron acceptor (in aerobic respiration / oxidative phosphorylation) ;\n5 adding cyanide stops, (aerobic) respiration / oxidative phosphorylation ;\n© Cambridge University Press & Assessment 2025 Page 14 of 14", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2025-May-June/ms/9700_s25_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-may-june/9700_s25_ms_54.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s25_ms_54-p12.png", "../answer-assets/9700_s25_ms_54-p13.png", "../answer-assets/9700_s25_ms_54-p14.png" ] }, { "id": "9700-2025-on-41-q01", "question_id": "9700-2025-on-41-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) AABB AABb AaBB AaBb ; ; 2\n\n1(a)(ii) long chocolate ; 1\n\n1(b) 4\nA A a a A A a a ;\nB b B b B b B b\nAB Ab aB Ab\nAB\nAABB AABb AaBB AaBb\nAb\nAABb AAbb AaBb Aabb\naB\nAaBB AaBb aaBB aaBb\nAb\nAaBb Aabb aaBb aabb ;\nF2 offspring phenotype number ratio:\n9 : 3 : 3 : 1 ;\nshort short long long\nblack chocolate black chocolate ;\nMp 4 need phenotypes linked to genotypes by colour, symbol or initials\n\n1(c) 1 structural gene codes for, (named) structural / functional, protein / polypeptide ; 2\n2 regulatory gene codes for, transcription factor / repressor protein\nor\nregulatory gene, controls / helps / restricts, expression of (other) genes ;\n© Cambridge University Press & Assessment 2025 Page 8 of 18", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p08.png" ] }, { "id": "9700-2025-on-41-q02", "question_id": "9700-2025-on-41-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) 2\nE. turcicum Z. mays\n1 chitin cell wall cellulose cell wall\nstructural or or\ndifference no chloroplasts chloroplasts\nor or\nhyphae / cells long and branching no hyphae / cells not long and branching\nor or\nsyncytial / multinucleate / several nuclei per cell one nucleus per cell ;\n2 heterotroph(ic) / parasitic / obtain food from host / do autotroph(ic) / phototrophic\nfunctional not photosynthesise / photosynthesis(e) ;\ndifference\n\n2(a)(ii) any four from: 4\n1 large groups divide into smaller groups ;\n2 common / similar / shared, features within a group ;\n3 ref. three of: kingdom – phylum – class – order – family ;\n4 genus and species = binomial / Linnaean / Latin / scientific, name ;\n5 (both in domain) Eukarya ;\n6 different kingdoms / Fungi and Plantae ;\n\n2(b)(i) any two from: 2\n1 low percentage leaf damage means high resistance (to infection) ;\n2 SKV50 = 22% and CML153 = 58% ;\n3 SKV50 shows greater resistance (to infection) ;\n\n2(b)(ii) continuous ; 1\n© Cambridge University Press & Assessment 2025 Page 9 of 18\n\n2(b)(iii) any four from: 4\n1 many / different / several / multiple, genes ;\n2 affect, same trait / (percentage) area of leaf damage / resistance ;\n3 alleles of, one / each, gene have a small effect ;\n4 (different) genes have, additive / combined / interactive, effects ;\n5 mathematical treatment to illustrate additive effect ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p09.png", "../answer-assets/9700_w25_ms_41-p10.png" ] }, { "id": "9700-2025-on-41-q03", "question_id": "9700-2025-on-41-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "3(a)(i) 0.95 (no units) ; ; 2\n\n3(a)(ii) any two from: 2\n1 B, run for less time / stopped early ;\n2 chlorophyll, converted / changed, to phaeophytin ;\n3 AVP ;\n\n3(a)(iii) any one from: 1\n1 different solvents ;\n2 different, TLC plate / chromatogram / stationary phase (material) ;\n3 different temperatures ;\n© Cambridge University Press & Assessment 2025 Page 10 of 18\n\n3(b) any four from: 4\nsimilarities\n1 both absorb, blue / between 400 and 475 nm ;\n2 both absorb, little / no, light between 525 and, 600 / 630, nm\nor\nboth absorb, little / no, green / yellow, light ;\n3 AVP ;\nmax three differences\n4 chlorophyll a absorbs, at more / a larger range of, wavelengths ;\n5 chlorophyll a absorbs, more / better, between 400 and 445 nm ;\n6 carotenoids absorb, more / better, between 445 and 525 nm ;\n7 chlorophyll a absorbs between, 600 / 640, and, 680 / 690 nm, and carotenoids do not ;\n8 chlorophyll a (blue absorption) peak / highest, at 425 / 430 nm and\ncarotenoids (blue absorption) peak / highest, at 460 / 465 nm ;\n9 chlorophyll a has blue peak and red peak but\ncarotenoids have two blue peaks and no red peak\nor\nchlorophyll a has two peaks but\ncarotenoids have three peaks ;\n\n3(c) any four from: 4\n1 gibberellin, moves to / acts on / stimulates, aleurone layer ;\n2 binds to, (gibberellin) receptor / GID(1) ;\n3 breaks down DELLA (protein) ;\n4 releases, PIF / transcription factor ;\n5 switches on gene for, amylase / maltase / protease ;\n6 amylase, breaks down / hydrolyses, starch to maltose ;\n7 sugars / glucose, for, respiration / growth, of embryo ;\n© Cambridge University Press & Assessment 2025 Page 11 of 18", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p10.png", "../answer-assets/9700_w25_ms_41-p11.png" ] }, { "id": "9700-2025-on-41-q04", "question_id": "9700-2025-on-41-q04", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 11, "status": "available", "reason": null, "text": "4(a) 1 diploid ; 3\n2 allele ;\n3 dominant (allele) ;\n\n4(b) any four from: 4\n1 CDV acts as a selection pressure ;\n2 DNA / allele, for black (coat) gives resistance to CDV\nor\nDNA / allele, for black (coat), gives (selective) advantage / is selected for, if / when, CDV is common / dogs are\ncommon ;\nin the south (context must be established at least once):\n3 more CDV (infection) in wolves ;\n4 black wolves, more likely to survive / have selective advantage / are selected for ; ORA greys\n5 black wolves more likely to, breed / reproduce ; ORA greys\n6 pass on / increase the frequency of, allele for black coat ; ORA grey\n\n4(c) 1 positive (linear) correlation / positive relationship / direct relationship / directly proportional 4\nor\nas % with (anti-CDV) antibodies increases the % of black wolvesincreases ;\nplus any three from:\n2 wolves that survive CDV will, later / as a result, have antibodies ;\n3 high % of antibodies show population with high level of CDV ;\n4 in population with high % antibodies, grey wolves have died / more black wolves are left ;\n5 gene / DNA / allele / protein, that gives black coat, helps survival / gives resistance to CDV / defends against CDV ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 12 of 18", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p12.png" ] }, { "id": "9700-2025-on-41-q05", "question_id": "9700-2025-on-41-q05", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 13, "status": "available", "reason": null, "text": "5(a) 3\nfeature ADH glucagon insulin\nbinds to receptors on cell surface\n✓ ✓ ✓ ;\nmembranes\nresults in molecules moving from\n✓ ✓  ;\ncells into the blood\nis secreted as a result of detection by\n✓   ;\nosmoreceptors\n\n5(b) any four from: 4\n1 impulses / action potentials / neurotransmitters, in nervous system and hormones in endocrine system ;\n2 electrical in nervous system and chemical in endocrine system ;\n3 neurones / nerve cells, in nervous system and blood in endocrine system ;\n4 effects are / target is, specific / localised, in nervous system and (can be) widespread in endocrine system ;\n5 effect / response, happens quickly in nervous system and slowly in endocrine system ;\n6 effect / response, lasts a short time in nervous system and long time in endocrine system ;\n7 AVP ;\n\n5(c)(i) C ; 1\n\n5(c)(ii) B ; 1\n© Cambridge University Press & Assessment 2025 Page 13 of 18\n\n5(c)(iii) 1 (D / it), shortens / contracts / decreases ; 4\nand any three from:\n2 calcium ions / Ca2+, bind to troponin ;\n3 tropomyosin, moves / shifts position / exposes binding sites on actin ;\n4 myosin (head) binds to actin / myosin-actin cross-bridges form ;\n5 power stroke / myosin head, pulls actin ;\n6 more actin, enters / overlaps with, A band / B\nor\nmore overlap between actin and myosin ;\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p13.png", "../answer-assets/9700_w25_ms_41-p14.png" ] }, { "id": "9700-2025-on-41-q06", "question_id": "9700-2025-on-41-q06", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) any three from: 3\n1 identify / protect / prioritise, species most at risk ;\n2 provide data to / advise, governments / scientists / zoos / industry ;\n3 so action can be taken to protect a species ;\n4 example of conservation action ;\n5 AVP ;\n\n6(a)(ii) in Europe / west or where, endangered / EN (context must be stated) 2\n1 P. arion less abundant (compared to, Asia / NT) ;\n2 more threatened / higher risk of extinction ;\n3 AVP ;\n\n6(b)(i) 1 habitat, degradation / change / loss ; 2\n2 due to, (change in) farming / development ;\n3 lack of, food plants / flowers for food ;\n© Cambridge University Press & Assessment 2025 Page 14 of 18\n\n6(b)(ii) any four from: 4\n1 prevent extinction / allow survival (of species) ;\n2 maintain / increase, biodiversity ;\n3 aesthetic / recreational / wellbeing (reasons / benefits) ;\n4 for, scientific interest / research / education ;\n5 ethical / moral / stewardship (obligation) ;\n6 local cultural significance / save local heritage / ecotourism ;\n7 maintain / protect / restore / stability of, food chains / food webs ;\n8 pollination / ecosystem, services ;\nQuestion Answer Marks", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p14.png", "../answer-assets/9700_w25_ms_41-p15.png" ] }, { "id": "9700-2025-on-41-q07", "question_id": "9700-2025-on-41-q07", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "7(a) any three from: 3\n1 breaks down / hydrolyses to / converted to, ADP / AMP, and Pi ;\n2 releases energy / energy donor ;\n3 reversible reaction / high turnover / can be regenerated ;\n4 small / soluble, so can, diffuse / move (freely), in cell ;\n5 AVP ;\n\n7(b) any six from: 6\n1 ETC / electron flow, less / stops ;\n2 no / less, energy, available / released / supplied (from electron flow) ;\n3 no / fewer, H+ ions / protons, pumped to intermembrane space ;\n4 no / smaller, H+ / proton, gradient ;\n5 no / fewer, protons diffuse through ATP synthase ;\n6 no / fewer, electrons reach, last carrier / end of chain ;\n7 no / fewer, electrons can react with oxygen to form water ;\n8 (oxidised) NAD not regenerated / lack of NAD ;\n9 no / less, glycolysis / link reaction / Krebs cycle ;\n10 AVP ;\n© Cambridge University Press & Assessment 2025 Page 15 of 18", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p15.png" ] }, { "id": "9700-2025-on-41-q08", "question_id": "9700-2025-on-41-q08", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "8(a) any four from: 4\n1 (Liberty Link soybean / it, is) not harmed by / not killed by / resistant to, herbicide / glufosinate ;\n2 herbicide / glufosinate, kills, weeds / unwanted plants ;\n3 reduces / removes / less / no, competition (with, weeds / unwanted plants) ;\n4 ref. to (sun)light / water / (named) soil minerals ;\n5 higher yield or more crop, harvested / produced ;\n6 AVP ;\n\n8(b)(i) restriction, enzyme / endonuclease ; 1\n\n8(b)(ii) (DNA) ligase ; 1\n\n8(c) any three from: 3\nsome / other / 21, countries:\n1 may, have, unsuitable / described problem in, climate / weather / soil ;\n2 no regulatory approval / may have banned (GM / Liberty Link) ;\n3 may have, (activist) groups / people, opposed to GM crops ;\n4 may not have land space available ;\n5 may have banned, herbicide / glufosinate ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 16 of 18", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p16.png" ] }, { "id": "9700-2025-on-41-q09", "question_id": "9700-2025-on-41-q09", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 6, "status": "available", "reason": null, "text": "9(a) (X =) (renal) pelvis ; 2\n(Y =) medulla ;\n\n9(b) any four from: 4\n1 glucose oxidase (present / immobilised, in sensor / on strip) ;\n2 glucose → hydrogen peroxide ;\n3 hydrogen peroxide (oxidised) → oxygen / electrons ;\n4 (magnitude of) e– flow / current / voltage, (generated) is proportional to, hydrogen peroxide / glucose, concentration ;\n5 digital / numerical / quantitative, reading / result / value (on screen) ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 17 of 18", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p17.png" ] }, { "id": "9700-2025-on-41-q10", "question_id": "9700-2025-on-41-q10", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 6, "status": "available", "reason": null, "text": "10 marks from any two groups of mark points to max 6: 6\n1 mutant TYR gene codes for non-functioning tyrosinase ;\n2 albinism / albino, recessive (disorder / allele) ;\n3 lack of melanin / no melanin produced ;\n4 giving, pale / fair, skin / hair or giving, transparent / pink, iris ;\n5 mutant HBB gene codes for, abnormal (β) globin / haemoglobin S ;\n6 sickle cell, anaemia / disease, codominant (disorder / allele) ;\n7 less soluble / sticky / rod-forming, haemoglobin makes red blood cells sickle ;\n8 sickle cells, block capillaries / cause pain (in low O conditions) ;\n2\n9 mutant F8 gene codes for non-functional factor VIII ;\n10 haemophilia, recessive / sex-linked / on X chromosome ;\n11 fibrinogen not changed to fibrin ;\n12 blood clotting problem / risk of excessive bleeding ;\n13 mutant HTT gene codes for abnormal huntingtin protein ;\n14 Huntington’s disease dominant (disorder / allele) ;\n15 ref. to additional / number of, CAG repeats ;\n16 cognitive / movement, difficulty ;\nother human genetic conditions (max 2 conditions with 4 possible marks each)\n17 mutant named gene codes for abnormal named protein ; ;\n18 type of allele that causes named condition ; ;\n19 biochemical detail re. gene / protein / molecule ; ;\n20 physiological effect ; ;\n© Cambridge University Press & Assessment 2025 Page 18 of 18", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_41.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_41-p18.png" ] }, { "id": "9700-2025-on-42-q01", "question_id": "9700-2025-on-42-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "1(a) A oxygen ; 3\nB ethanol ;\nC aerenchyma ;\n\n1(b) ref. to ethanol dehydrogenase (to break it down) ; A alcohol dehydrogenase 1\n\n1(c)(i) as gibberellin concentration increases, the length of stem increases 2\nor\npositive correlation between concentration of gibberellin and length of stem ;\ndata quote – two concentrations and two lengths with units ;\nconc gibberellin / au length of stem /\nmm ± 0.5 mm\n1 3\n2 19\n3 27\n4 45\n5 52\n© Cambridge University Press & Assessment 2025 Page 8 of 23\n\n1(c)(ii) any three from : 3\n1 ethylene causes break down of ABA, so gibberellin, active / stimulated / functional ;\n2 plants grow tall(er) / stems increase in length / stem elongation / increase in internodal length ;\n3 (so) leaves / flowers, held above the water ;\n4 (so) photosynthesis can occur / increased access to light / AW\nor\n(so) gas exchange / reproduction, can occur ;\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p08.png", "../answer-assets/9700_w25_ms_42-p09.png" ] }, { "id": "9700-2025-on-42-q02", "question_id": "9700-2025-on-42-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "2(a) gene 3\na section of DNA / sequence of (DNA) bases, coding for a (specific) polypeptide ;\ngenotype\nall the alleles / alleles in an organism / (two) alleles of one gene ;\nphenotype\n(observable) features / characteristics / traits / appearance, (of an organism) ;\n© Cambridge University Press & Assessment 2025 Page 9 of 23\n\n2(b) any four from: 5\n1 mate / breed / cross, homozygous (parents) ;\n2 dominant (parent) with recessive (parent) ;\n3 to produce the F1, offspring / generation ;\n4 (F1) offspring are heterozygotes ;\n5 mate / breed / cross, F1 offspring / F1 generation / heterozygotes\nor\nself an F1 offspring (plant) ;\n6 to produce the F2, offspring / generation ;\nplus\n7 25% (F2) offspring are, homozygous dominant, / AA\nand 50% are, heterozygotes / Aa\nand 25% are, homozygous recessive / aa ;\nA a ratio e.g. AA Aa Aa aa\n1 : 2 : 1\n© Cambridge University Press & Assessment 2025 Page 10 of 23", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p09.png", "../answer-assets/9700_w25_ms_42-p10.png" ] }, { "id": "9700-2025-on-42-q03", "question_id": "9700-2025-on-42-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 12, "status": "available", "reason": null, "text": "3(a)(i) any three from: 3\n1 glucose diffuses into the cell (through, A / transport protein) ;\n2 idea that the enzyme / B, loses phosphate group ;\n3 (dephosphorylated) B binds to lactose permease ;\n4 causes, shape change / allosteric change, to lactose permease ;\n5 lactose permease cannot function (so lactose cannot enter) ;\n\n3(a)(ii) any two from: 2\n1 no / less, (protein) synthesis of, lactose permease / β-galactosidase / transacetylase\nor\nno / less, transcription / expression, of (named structural) genes (of lac operon) ;\n2 no / less, ATP / energy, wasted ;\n3 no / fewer, amino acids wasted ;\n4 glucose is respired more easily / AW\nor\nfewer steps / less energy, required to break down glucose\nor\nlactose has to be broken down (to glucose and galactose) ;\n© Cambridge University Press & Assessment 2025 Page 11 of 23\n\n3(a)(iii) any three from: 3\n1 splits into / forms, two, triose phosphate / TP (molecules) ;\n2 (TP) oxidised / dehydrogenated, to pyruvate ;\n3 ATP production ;\n4 substrate-linked phosphorylation ;\n5 production of reduced NAD ;\n© Cambridge University Press & Assessment 2025 Page 12 of 23\n\n3(b)(i) any two from: 2\nlactose diet\n1 increases (over six days) ;\nno lactose diet\n2 small increase / increases slightly / little change / stays around 50% (over six days) ;\n3 comparative data quote – 2 percentages of either diet over time\nor\npercentage of each diet on one day ;\ntime / days percentage lac+ ± 0.5 mm\nlactose diet no lactose diet\n0 50 50\n1 65.5 54\n2 75.5 56.5\n3 83.5 60\n4 84 59\n5 85 57.5\n6 86 57\n© Cambridge University Press & Assessment 2025 Page 13 of 23\n\n3(b)(ii) any two from: 2\n1 lactose is the selection pressure ;\n2 (lac+), can metabolise / take up / AW, lactose (so survive)\nor\nlac-, cannot metabolise / take up / AW, lactose (so die) ;\n3 AVP ; e.g. ref. glucose has run out\nQuestion Answer Marks", "source_pages": [ 11, 12, 13, 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p11.png", "../answer-assets/9700_w25_ms_42-p12.png", "../answer-assets/9700_w25_ms_42-p13.png", "../answer-assets/9700_w25_ms_42-p14.png" ] }, { "id": "9700-2025-on-42-q04", "question_id": "9700-2025-on-42-q04", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 6, "status": "available", "reason": null, "text": "4(a) 1 mutation ; 2\n2 horizontal transmission / conjugation / transformation / transduction ;\n\n4(b) idea of tracking, mutations / resistance genes / resistance alleles 1\nor\nidentifies mechanisms of resistance\nor\n(informed) choice / production, of antibiotic ;\n\n4(c) any three from: 3\n1 streptomycin is selection pressure ;\n2 bacteria with, mutation / resistance, survive / reproduce / have a selective advantage ; ora\n3 allele / gene, for resistance passed on ;\n4 directional selection ;\n© Cambridge University Press & Assessment 2025 Page 14 of 23", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p14.png" ] }, { "id": "9700-2025-on-42-q05", "question_id": "9700-2025-on-42-q05", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 14, "status": "available", "reason": null, "text": "5(a) any four from: 4\nmark as pairs\nName 1 dNTPs / DNA nucleotides ;\nExplanation 1 to, anneal / bind, to complementary bases ;\nName 2 Taq polymerase ;\nExplanation 2 to make, phosphodiester bonds / the sugar phosphate backbone / double-stranded DNA / a complementary\nstrand of DNA\nor\nref. to functioning at higher temperature / does not denature at the higher temperature / is thermostable ;\nName 3 buffer ;\nExplanation 3 to provide, optimum / suitable / constant, pH for, polymerase / DNA\nor\nprevents, denaturation of polymerase / damage to DNA ;\n\n5(b)(i) any two from: 2\n1 (DNA ladder) compared to (other fragments) ;\n2 ref. to (estimate) length of (DNA) fragment / to identify the fragment number ;\n3 ref. to show electrophoresis worked correctly ;\n© Cambridge University Press & Assessment 2025 Page 15 of 23\n\n5(b)(ii) any three from: 3\n1 (PCR) amplifies / makes many copies of, DNA (fragments) ;\n2 (PCR) ref. to selecting fragments, small enough / less than 1000 bp / not more than 916 bp (for sequencing) ;\n3 (electrophoresis) separate the (DNA) fragments ;\n4 (electrophoresis) confirms / identifies, fragment lengths / fragment number / PCR worked correctly ;\n\n5(c) (235 =) 3.4  1010 ; 1\n\n5(d) any four from: 4\n1 child may have disease when, neither parent has the disease / no family history ;\n2 early, detection / treatment (for gene therapy to work) ;\n3 improve, quality of life / life expectancy ;\n4 ref. to informs family planning (for future pregnancies) ;\n5 idea that it does not involve additional sampling ;\n6 (screening is) expensive ;\n7 treatment / gene therapy, expensive ;\n8 test may not always be accurate ;\n9 long-term effect of treatment, unknown / negative ;\n© Cambridge University Press & Assessment 2025 Page 16 of 23", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p15.png", "../answer-assets/9700_w25_ms_42-p16.png" ] }, { "id": "9700-2025-on-42-q06", "question_id": "9700-2025-on-42-q06", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "6(a) any four from : 4\n1 less / no, PKB, activated / stimulated ;\n2 fewer / no, vesicles, move to / fuse with, cell surface membrane ;\n3 fewer / no, GLUT4 (transport proteins) added to (cell surface) membrane\nor\n(cell surface) membrane, less / not, permeable to glucose ;\n4 less / no, glucose taken up by facilitated diffusion (into muscle cells) ;\n5 blood glucose concentration, (remains) high(er) / does not decrease ;\n\n6(b) any seven from : 7\n1 (biosensor has) glucose oxidase (immobilised on recognition layer) ;\n2 blood sample added ;\n3 glucose (in blood) passes through, partially / selectively, permeable membrane ;\n4 glucose oxidase, oxidises glucose / converts glucose / catalyses glucose reaction ;\n5 gluconic acid and hydrogen peroxide formed ;\n6 reaction converted to a current (by transducer) ;\n7 current is amplified ;\n8 digital / numerical / quantitative, reading ;\n9 size of current is proportional to glucose concentration ;\n10 instant result / accurate ;\n© Cambridge University Press & Assessment 2025 Page 17 of 23", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p17.png" ] }, { "id": "9700-2025-on-42-q07", "question_id": "9700-2025-on-42-q07", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 7, "status": "available", "reason": null, "text": "7(a)(i) any one from : 1\nsoil contains few (named mineral) ions ;\nlocated in, shaded areas / areas of low light intensity ;\n\n7(a)(ii) to attract insects ; 1\n\n7(a)(iii) energy / ATP, not wasted (responding to a non-edible object) ; 1\n\n7(a)(iv) (time) for, digestion / enzyme action / absorption / assimilation ; 1\n\n7(b) any three from : 3\n1 impulses / action potentials, are discrete events / AW ;\n2 impulses / action potentials, are unidirectional ;\n3 determines / limits, the frequency of, impulses / action potentials ;\n4 AVP ; e.g. 200-300 action potentials per second\n© Cambridge University Press & Assessment 2025 Page 18 of 23", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p18.png" ] }, { "id": "9700-2025-on-42-q08", "question_id": "9700-2025-on-42-q08", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "8(a) any four from : 4\n1 (named) protected reserves ;\n2 limit palm oil plantations / ref. to sustainable palm oil production ;\n3 restoring lost habitat / reforestation / reduce deforestation ;\n4 captive breeding programs ;\n5 release into wild ;\n6 ban, hunting / trade;\n7 raise awareness / education ;\n8 ref. to research ;\n\n8(b) 1 ecosystem / habitat (diversity) ; 3\n2 species (diversity / richness) ;\n3 genetic (diversity) ;\n\n8(c)(i) 0.2034 ; 2\n0.3072 ;\nallow ecf for mp2 if both incorrect\nallow ecf for mp2 if figure correct in both but not to 4dp\n\n8(c)(ii) 0.6928 / 0.693 ; 1\nallow ecf for 1 minus their answer to 8ci\n© Cambridge University Press & Assessment 2025 Page 19 of 23\n\n8(c)(iii) (D) close(r) to 1 / higher than 0.5 ; 2\n(so) high(er) (bio)diversity ;\nQuestion Answer Marks", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p19.png", "../answer-assets/9700_w25_ms_42-p20.png" ] }, { "id": "9700-2025-on-42-q09", "question_id": "9700-2025-on-42-q09", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "9(a)(i) absorption spectrum 2\nabsorption of different wavelengths (of light) by (named) pigment(s) ;\naction spectrum\nrate of photosynthesis at different wavelengths (of light) ;\n\n9(a)(ii) any three from : 3\n1 chlorophyll b / carotenoids / accessory pigments (are present) ;\n2 (these other pigments) absorb light (energy), between 450 and 550 nm / of wavelengths that chlorophyll a does\nnot absorb ;\n3 energy passed on to, reaction centre / chlorophyll a / primary pigment ;\n4 for, light-dependent reactions / photophosphorylation / photolysis (of water) / photoactivation ;\n© Cambridge University Press & Assessment 2025 Page 20 of 23\n\n9(b)(i) any four from : 4\n1 increase then decrease ;\n2 optimum temperature at 29 C ;\n3 data quote – two temperatures and two rates with units ;\ntemperature / C rate of photosynthesis / mg g-1 h-1\n±0.5 ±0.05\n2.5 0.75\n5 1.1\n10 1.8\n20 2.95\n29 3.5\n30 3.45\n40 2.65\n45 1.5\n48 0.5\nincrease / before 29 C\n4 more kinetic energy for, enzyme (activity) / AW ;\n5 temperature is the limiting factor ;\ndecrease / after 29 C\n6 denaturation of, rubisco / enzymes / oxygen-evolving complex ;\n7 AVP ; e.g. photorespiration limiting the rate at above 25 C\n© Cambridge University Press & Assessment 2025 Page 21 of 23\n\n9(b)(ii) 3.525 to 3.675 ; 2\nmg g–1 h–1 ;\nQuestion Answer Marks", "source_pages": [ 20, 21, 22 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p20.png", "../answer-assets/9700_w25_ms_42-p21.png", "../answer-assets/9700_w25_ms_42-p22.png" ] }, { "id": "9700-2025-on-42-q10", "question_id": "9700-2025-on-42-q10", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "10(a) any three from : 3\n1 myelin sheath / Schwann cells, acts as an insulator / prevents movement of ions ;\n2 depolarisation / action potential, only occurs at the nodes ; I impulses\n3 action potentials jump from node to node / saltatory conduction ; I impulses\n4 long(er) local circuits ;\n5 AVP ; e.g. wide axon diameter\n\n10(b) any four from : 4\n1 ACh binds to receptors on sarcolemma ;\n2 (ligand-gated) Na+ channels open\nor\nNa+ enters, muscle cell / sarcoplasm ;\n3 sarcolemma depolarised ;\n4 depolarisation / action potential, spreads, to / down, T-tubules ;\n5 voltage-gated Ca2+ channels open ;\n6 Ca2+, diffuse / move, out of sarcoplasmic reticulum (and bind to troponin) ;\n© Cambridge University Press & Assessment 2025 Page 22 of 23\n\n10(c) any three from : 3\n1 (decreased rate of respiration so), no / less, ATP produced ;\n2 no / less, Ca2+ pumped back into sarcoplasmic reticulum ;\n3 no / less, release of myosin heads from actin / cross bridges broken\nor\nno / less, hydrolysis of ATP by myosin head / return of myosin head to original position ; AW\n4 sarcomere, permanently contracted / cannot relax ; A paralysis\n5 slower sarcomere contraction / less sarcomere shortening / weaker power stroke ;\n© Cambridge University Press & Assessment 2025 Page 23 of 23", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_42.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_42-p22.png", "../answer-assets/9700_w25_ms_42-p23.png" ] }, { "id": "9700-2025-on-43-q01", "question_id": "9700-2025-on-43-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "1(a)(i) AABB AABb AaBB AaBb ; ; 2\n\n1(a)(ii) long chocolate ; 1\n\n1(b) 4\nA A a a A A a a ;\nB b B b B b B b\nAB Ab aB Ab\nAB\nAABB AABb AaBB AaBb\nAb\nAABb AAbb AaBb Aabb\naB\nAaBB AaBb aaBB aaBb\nAb\nAaBb Aabb aaBb aabb ;\nF2 offspring phenotype number ratio:\n9 : 3 : 3 : 1 ;\nshort short long long\nblack chocolate black chocolate ;\nMp 4 need phenotypes linked to genotypes by colour, symbol or initials\n\n1(c) 1 structural gene codes for, (named) structural / functional, protein / polypeptide ; 2\n2 regulatory gene codes for, transcription factor / repressor protein\nor\nregulatory gene, controls / helps / restricts, expression of (other) genes ;\n© Cambridge University Press & Assessment 2025 Page 8 of 18", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p08.png" ] }, { "id": "9700-2025-on-43-q02", "question_id": "9700-2025-on-43-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) 2\nE. turcicum Z. mays\n1 chitin cell wall cellulose cell wall\nstructural or or\ndifference no chloroplasts chloroplasts\nor or\nhyphae / cells long and branching no hyphae / cells not long and branching\nor or\nsyncytial / multinucleate / several nuclei per cell one nucleus per cell ;\n2 heterotroph(ic) / parasitic / obtain food from host / do autotroph(ic) / phototrophic\nfunctional not photosynthesise / photosynthesis(e) ;\ndifference\n\n2(a)(ii) any four from: 4\n1 large groups divide into smaller groups ;\n2 common / similar / shared, features within a group ;\n3 ref. three of: kingdom – phylum – class – order – family ;\n4 genus and species = binomial / Linnaean / Latin / scientific, name ;\n5 (both in domain) Eukarya ;\n6 different kingdoms / Fungi and Plantae ;\n\n2(b)(i) any two from: 2\n1 low percentage leaf damage means high resistance (to infection) ;\n2 SKV50 = 22% and CML153 = 58% ;\n3 SKV50 shows greater resistance (to infection) ;\n\n2(b)(ii) continuous ; 1\n© Cambridge University Press & Assessment 2025 Page 9 of 18\n\n2(b)(iii) any four from: 4\n1 many / different / several / multiple, genes ;\n2 affect, same trait / (percentage) area of leaf damage / resistance ;\n3 alleles of, one / each, gene have a small effect ;\n4 (different) genes have, additive / combined / interactive, effects ;\n5 mathematical treatment to illustrate additive effect ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p09.png", "../answer-assets/9700_w25_ms_43-p10.png" ] }, { "id": "9700-2025-on-43-q03", "question_id": "9700-2025-on-43-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 13, "status": "available", "reason": null, "text": "3(a)(i) 0.95 (no units) ; ; 2\n\n3(a)(ii) any two from: 2\n1 B, run for less time / stopped early ;\n2 chlorophyll, converted / changed, to phaeophytin ;\n3 AVP ;\n\n3(a)(iii) any one from: 1\n1 different solvents ;\n2 different, TLC plate / chromatogram / stationary phase (material) ;\n3 different temperatures ;\n© Cambridge University Press & Assessment 2025 Page 10 of 18\n\n3(b) any four from: 4\nsimilarities\n1 both absorb, blue / between 400 and 475 nm ;\n2 both absorb, little / no, light between 525 and, 600 / 630, nm\nor\nboth absorb, little / no, green / yellow, light ;\n3 AVP ;\nmax three differences\n4 chlorophyll a absorbs, at more / a larger range of, wavelengths ;\n5 chlorophyll a absorbs, more / better, between 400 and 445 nm ;\n6 carotenoids absorb, more / better, between 445 and 525 nm ;\n7 chlorophyll a absorbs between, 600 / 640, and, 680 / 690 nm, and carotenoids do not ;\n8 chlorophyll a (blue absorption) peak / highest, at 425 / 430 nm and\ncarotenoids (blue absorption) peak / highest, at 460 / 465 nm ;\n9 chlorophyll a has blue peak and red peak but\ncarotenoids have two blue peaks and no red peak\nor\nchlorophyll a has two peaks but\ncarotenoids have three peaks ;\n\n3(c) any four from: 4\n1 gibberellin, moves to / acts on / stimulates, aleurone layer ;\n2 binds to, (gibberellin) receptor / GID(1) ;\n3 breaks down DELLA (protein) ;\n4 releases, PIF / transcription factor ;\n5 switches on gene for, amylase / maltase / protease ;\n6 amylase, breaks down / hydrolyses, starch to maltose ;\n7 sugars / glucose, for, respiration / growth, of embryo ;\n© Cambridge University Press & Assessment 2025 Page 11 of 18", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p10.png", "../answer-assets/9700_w25_ms_43-p11.png" ] }, { "id": "9700-2025-on-43-q04", "question_id": "9700-2025-on-43-q04", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 11, "status": "available", "reason": null, "text": "4(a) 1 diploid ; 3\n2 allele ;\n3 dominant (allele) ;\n\n4(b) any four from: 4\n1 CDV acts as a selection pressure ;\n2 DNA / allele, for black (coat) gives resistance to CDV\nor\nDNA / allele, for black (coat), gives (selective) advantage / is selected for, if / when, CDV is common / dogs are\ncommon ;\nin the south (context must be established at least once):\n3 more CDV (infection) in wolves ;\n4 black wolves, more likely to survive / have selective advantage / are selected for ; ORA greys\n5 black wolves more likely to, breed / reproduce ; ORA greys\n6 pass on / increase the frequency of, allele for black coat ; ORA grey\n\n4(c) 1 positive (linear) correlation / positive relationship / direct relationship / directly proportional 4\nor\nas % with (anti-CDV) antibodies increases the % of black wolvesincreases ;\nplus any three from:\n2 wolves that survive CDV will, later / as a result, have antibodies ;\n3 high % of antibodies show population with high level of CDV ;\n4 in population with high % antibodies, grey wolves have died / more black wolves are left ;\n5 gene / DNA / allele / protein, that gives black coat, helps survival / gives resistance to CDV / defends against CDV ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 12 of 18", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p12.png" ] }, { "id": "9700-2025-on-43-q05", "question_id": "9700-2025-on-43-q05", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 13, "status": "available", "reason": null, "text": "5(a) 3\nfeature ADH glucagon insulin\nbinds to receptors on cell surface\n✓ ✓ ✓ ;\nmembranes\nresults in molecules moving from\n✓ ✓  ;\ncells into the blood\nis secreted as a result of detection by\n✓   ;\nosmoreceptors\n\n5(b) any four from: 4\n1 impulses / action potentials / neurotransmitters, in nervous system and hormones in endocrine system ;\n2 electrical in nervous system and chemical in endocrine system ;\n3 neurones / nerve cells, in nervous system and blood in endocrine system ;\n4 effects are / target is, specific / localised, in nervous system and (can be) widespread in endocrine system ;\n5 effect / response, happens quickly in nervous system and slowly in endocrine system ;\n6 effect / response, lasts a short time in nervous system and long time in endocrine system ;\n7 AVP ;\n\n5(c)(i) C ; 1\n\n5(c)(ii) B ; 1\n© Cambridge University Press & Assessment 2025 Page 13 of 18\n\n5(c)(iii) 1 (D / it), shortens / contracts / decreases ; 4\nand any three from:\n2 calcium ions / Ca2+, bind to troponin ;\n3 tropomyosin, moves / shifts position / exposes binding sites on actin ;\n4 myosin (head) binds to actin / myosin-actin cross-bridges form ;\n5 power stroke / myosin head, pulls actin ;\n6 more actin, enters / overlaps with, A band / B\nor\nmore overlap between actin and myosin ;\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p13.png", "../answer-assets/9700_w25_ms_43-p14.png" ] }, { "id": "9700-2025-on-43-q06", "question_id": "9700-2025-on-43-q06", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 11, "status": "available", "reason": null, "text": "6(a)(i) any three from: 3\n1 identify / protect / prioritise, species most at risk ;\n2 provide data to / advise, governments / scientists / zoos / industry ;\n3 so action can be taken to protect a species ;\n4 example of conservation action ;\n5 AVP ;\n\n6(a)(ii) in Europe / west or where, endangered / EN (context must be stated) 2\n1 P. arion less abundant (compared to, Asia / NT) ;\n2 more threatened / higher risk of extinction ;\n3 AVP ;\n\n6(b)(i) 1 habitat, degradation / change / loss ; 2\n2 due to, (change in) farming / development ;\n3 lack of, food plants / flowers for food ;\n© Cambridge University Press & Assessment 2025 Page 14 of 18\n\n6(b)(ii) any four from: 4\n1 prevent extinction / allow survival (of species) ;\n2 maintain / increase, biodiversity ;\n3 aesthetic / recreational / wellbeing (reasons / benefits) ;\n4 for, scientific interest / research / education ;\n5 ethical / moral / stewardship (obligation) ;\n6 local cultural significance / save local heritage / ecotourism ;\n7 maintain / protect / restore / stability of, food chains / food webs ;\n8 pollination / ecosystem, services ;\nQuestion Answer Marks", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p14.png", "../answer-assets/9700_w25_ms_43-p15.png" ] }, { "id": "9700-2025-on-43-q07", "question_id": "9700-2025-on-43-q07", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "7(a) any three from: 3\n1 breaks down / hydrolyses to / converted to, ADP / AMP, and Pi ;\n2 releases energy / energy donor ;\n3 reversible reaction / high turnover / can be regenerated ;\n4 small / soluble, so can, diffuse / move (freely), in cell ;\n5 AVP ;\n\n7(b) any six from: 6\n1 ETC / electron flow, less / stops ;\n2 no / less, energy, available / released / supplied (from electron flow) ;\n3 no / fewer, H+ ions / protons, pumped to intermembrane space ;\n4 no / smaller, H+ / proton, gradient ;\n5 no / fewer, protons diffuse through ATP synthase ;\n6 no / fewer, electrons reach, last carrier / end of chain ;\n7 no / fewer, electrons can react with oxygen to form water ;\n8 (oxidised) NAD not regenerated / lack of NAD ;\n9 no / less, glycolysis / link reaction / Krebs cycle ;\n10 AVP ;\n© Cambridge University Press & Assessment 2025 Page 15 of 18", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p15.png" ] }, { "id": "9700-2025-on-43-q08", "question_id": "9700-2025-on-43-q08", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "8(a) any four from: 4\n1 (Liberty Link soybean / it, is) not harmed by / not killed by / resistant to, herbicide / glufosinate ;\n2 herbicide / glufosinate, kills, weeds / unwanted plants ;\n3 reduces / removes / less / no, competition (with, weeds / unwanted plants) ;\n4 ref. to (sun)light / water / (named) soil minerals ;\n5 higher yield or more crop, harvested / produced ;\n6 AVP ;\n\n8(b)(i) restriction, enzyme / endonuclease ; 1\n\n8(b)(ii) (DNA) ligase ; 1\n\n8(c) any three from: 3\nsome / other / 21, countries:\n1 may, have, unsuitable / described problem in, climate / weather / soil ;\n2 no regulatory approval / may have banned (GM / Liberty Link) ;\n3 may have, (activist) groups / people, opposed to GM crops ;\n4 may not have land space available ;\n5 may have banned, herbicide / glufosinate ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 16 of 18", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p16.png" ] }, { "id": "9700-2025-on-43-q09", "question_id": "9700-2025-on-43-q09", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 6, "status": "available", "reason": null, "text": "9(a) (X =) (renal) pelvis ; 2\n(Y =) medulla ;\n\n9(b) any four from: 4\n1 glucose oxidase (present / immobilised, in sensor / on strip) ;\n2 glucose → hydrogen peroxide ;\n3 hydrogen peroxide (oxidised) → oxygen / electrons ;\n4 (magnitude of) e– flow / current / voltage, (generated) is proportional to, hydrogen peroxide / glucose, concentration ;\n5 digital / numerical / quantitative, reading / result / value (on screen) ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 17 of 18", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p17.png" ] }, { "id": "9700-2025-on-43-q10", "question_id": "9700-2025-on-43-q10", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 6, "status": "available", "reason": null, "text": "10 marks from any two groups of mark points to max 6: 6\n1 mutant TYR gene codes for non-functioning tyrosinase ;\n2 albinism / albino, recessive (disorder / allele) ;\n3 lack of melanin / no melanin produced ;\n4 giving, pale / fair, skin / hair or giving, transparent / pink, iris ;\n5 mutant HBB gene codes for, abnormal (β) globin / haemoglobin S ;\n6 sickle cell, anaemia / disease, codominant (disorder / allele) ;\n7 less soluble / sticky / rod-forming, haemoglobin makes red blood cells sickle ;\n8 sickle cells, block capillaries / cause pain (in low O conditions) ;\n2\n9 mutant F8 gene codes for non-functional factor VIII ;\n10 haemophilia, recessive / sex-linked / on X chromosome ;\n11 fibrinogen not changed to fibrin ;\n12 blood clotting problem / risk of excessive bleeding ;\n13 mutant HTT gene codes for abnormal huntingtin protein ;\n14 Huntington’s disease dominant (disorder / allele) ;\n15 ref. to additional / number of, CAG repeats ;\n16 cognitive / movement, difficulty ;\nother human genetic conditions (max 2 conditions with 4 possible marks each)\n17 mutant named gene codes for abnormal named protein ; ;\n18 type of allele that causes named condition ; ;\n19 biochemical detail re. gene / protein / molecule ; ;\n20 physiological effect ; ;\n© Cambridge University Press & Assessment 2025 Page 18 of 18", "source_pages": [ 18 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_43.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_43-p18.png" ] }, { "id": "9700-2025-on-44-q01", "question_id": "9700-2025-on-44-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "1(a) 1 A ; 4\n2 C ;\n3 F ;\n4 B ;\n\n1(b) any four from: 4\n1 no / less, Ca2+ / calcium ions, enter (synaptic knob / presynaptic neurone) ;\n2 no / less, vesicles of acetylcholine, move towards / fuse with / do exocytosis at, presynaptic membrane ;\n3 no / less, acetylcholine / ACh, binds to receptors (on postsynaptic membrane) ;\n4 no / less, Na+ / sodium ions, enter (postsynaptic neurone)\nor\nno / less, depolarisation of postsynaptic membrane ;\n5 no / fewer, actions potentials ;\nQuestion Answer Marks", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p08.png" ] }, { "id": "9700-2025-on-44-q02", "question_id": "9700-2025-on-44-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "2(a) anaphase: K and M ; 4\ncells containing pairs of homologous chromosomes: J and K ;\ncrossing over: J ;\nhaploid cells: L and M and N ;\n\n2(b) any two from: 2\n1 to prevent self-pollination / to ensure cross-pollination ;\n2 so, must cross with / other parent must be / pollen comes from, a, different / selected, plant / parent / individual /\nvariety ;\n3 to make plant a female parent ;\n© Cambridge University Press & Assessment 2025 Page 8 of 17\n\n2(c) any four from: 4\nstage 1 – inbreeding to get two lines\n1 inbreeding / line breeding ;\n2 select for, disease resistance / rapid growth / high yield ;\n3 select, best / desirable, offspring and cross with each other repeatedly ;\n4 (results in) homozygous (loci) ;\nstage 2 – outcross to get uniform vigorous offspring\n5 hybridise / outcross / outbreed, with another, variety / type of maize ;\n6 with a different desired trait ;\n7 AVP ;\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p08.png", "../answer-assets/9700_w25_ms_44-p09.png" ] }, { "id": "9700-2025-on-44-q03", "question_id": "9700-2025-on-44-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 11, "status": "available", "reason": null, "text": "3(a) any five from: 5\n1 restriction endonuclease ;\n2 (RE) cuts, bacterial / herbicide-resistance, gene / DNA ;\n3 (RE) cuts a, plasmid / vector ;\n4 DNA ligase joins, new / bacterial / foreign, gene to, plasmid / vector ;\n5 ref. to joining / adding, of promoter ;\n6 (promoter / regulatory sequence) ensures expression of (new / bacterial / foreign / prokaryotic) gene ;\n\n3(b) 73 / 100  123.5 2\nor\n90.155 million ;\n(90.155  2 =) 180.31 million ;\n© Cambridge University Press & Assessment 2025 Page 9 of 17\n\n3(c) any four from: 4\npositive implications:\n1 more food / higher yield (per hectare) ;\n2 (farmers) use less, insecticide / pesticide ;\n3 cheaper food prices for consumers ;\n4 less land needed to grow food leaves more for, biodiversity / conservation ;\n5 improved food nutritional value ;\nnegative implications:\n6 food allergies ;\n7 greater quantity of herbicide residue on food ;\n8 (evolution of) resistance in, insects / weeds / fungi / pests ;\n9 pollen drift to / cross-breeding with, organic / non-GM / conventional, crops ;\n10 GM crops may become invasive weeds ;\n11 consumer mistrust / GM food must be clearly labelled ;\nQuestion Answer Marks", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p09.png", "../answer-assets/9700_w25_ms_44-p10.png" ] }, { "id": "9700-2025-on-44-q04", "question_id": "9700-2025-on-44-q04", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "4(a)(i) 0.3 ; 1\n\n4(a)(ii) any four from: 4\n1 genetic drift ;\n2 (drift as) frequency, fluctuates / decreases and increases / shows random changes / does not change markedly in just\none direction ;\n3 directional selection ;\n4 from (generation) 2 to 7 / at first, T decreases as, T is selected against\nand\nfrom (generation) 7 to 13 / later, T increased as, T is selected for;\n5 may be, stabilising selection / selection for heterozygotes ;\n6 (stabilising selection) keeps relative allele frequencies roughly the same ;\n© Cambridge University Press & Assessment 2025 Page 10 of 17\n\n4(b) any three from: 3\n1 small(er) population ;\n2 causes (genetic) bottleneck (effect) ;\n3 chance events, have greater relative effect on / cause larger fluctuations in, allele frequency ;\n4 more likely for one allele to, replace another / go extinct / become fixed ;\n5 by chance T organisms, did not mate / pass on T allele\nor\nby chance offspring with T died ;\n\n4(c) Hardy-Weinberg ; 1\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p10.png", "../answer-assets/9700_w25_ms_44-p11.png" ] }, { "id": "9700-2025-on-44-q05", "question_id": "9700-2025-on-44-q05", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 12, "status": "available", "reason": null, "text": "5(a) any three from: 3\n1 small so can keep, in small space / for low cost / with low maintenance ;\n2 can select parents for, mating / cross-breeding / particular crosses ;\n3 so get many, offspring / generations, in a short time ;\n4 can be used to research, cancer / (named) neurodegenerative diseases ;\n5 AVP ;\n© Cambridge University Press & Assessment 2025 Page 11 of 17\n\n5(b) 6\n1 symbols: A = grey bodya = black body\nB = long wing b = short wing ;\nF1 phenotypes: grey long x grey long\n2 F1 genotypes: AaBb x (AaBb) ;\nAB Ab aB ab ;\nAB AABB AABb AaBB AaBb\nAb AABb AAbb AaBb Aabb\naB AaBB AaBb aaBB aaBb\nab AaBb Aabb aaBb aabb ;\n5 F2 offspring phenotype number ratio:\n9 : 3 : 3 : 1 ;\n6 grey grey black black\nlong short long short ;\n© Cambridge University Press & Assessment 2025 Page 12 of 17\n\n5(c) 1 carry out a test cross / cross with a double homozygous recessive fruit fly / 3\ncross with fly with black body and short wings ;\nplus any two from:\n2 if some offspring have black body then F2 fly is,\nheterozygous for the body colour (gene) / Aa ;\n3 if all offspring have grey body then F2 fly is,\nhomozygous dominant for body colour (gene) / AA ;\n4 if some offspring have short wings then F2 fly is,\nheterozygous for wing length (gene) / Bb ;\n5 if all offspring have long wings then F2 fly is,\nhomozygous dominant for wing length (gene) / BB ;\nQuestion Answer Marks", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p11.png", "../answer-assets/9700_w25_ms_44-p12.png", "../answer-assets/9700_w25_ms_44-p13.png" ] }, { "id": "9700-2025-on-44-q06", "question_id": "9700-2025-on-44-q06", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 13, "status": "available", "reason": null, "text": "6(a)(i) 1 blood glucose concentration increases until 30 minutes ; 2\n2 decreases to original value / returns to 5 mmol dm–3, by 90 minutes ;\n\n6(a)(ii) 83.3 ; ; 2\n\n6(a)(iii) any two from: 2\n1 reduce intake of (named) carbohydrate ;\n2 physical exercise ;\n3 inject insulin ;\n4 AVP ;\n© Cambridge University Press & Assessment 2025 Page 13 of 17\n\n6(b) any seven from : 7\n1 glucagon is, cell-signalling molecule / ligand / first messenger ;\n2 binds to receptor on liver cell (surface) membrane ;\n3 G-protein activated ;\n4 aden(yl)yl cyclase activated / formation of cAMP ;\n5 ref. to second messenger ;\n6 enzyme cascade / signal amplified ;\n7 glycogenolysis / glycogen hydrolysed to glucose ;\n8 gluconeogenesis / amino acids → glucose / triglycerides → glucose ;\n9 glucose released into blood ;\n10 AVP ;\nQuestion Answer Marks", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p13.png", "../answer-assets/9700_w25_ms_44-p14.png" ] }, { "id": "9700-2025-on-44-q07", "question_id": "9700-2025-on-44-q07", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 7, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 10, "status": "available", "reason": null, "text": "7(a) 1 phylum ; 3\n2 order ;\n3 Strigops ;\n\n7(b) any three from: 3\n1 no / few, humans ;\n2 no / few, predators ;\n3 sufficient, vegetation / food ;\n4 places to hide during day ;\n5 AVP ;\n\n7(c) any four from: 4\n1 inbreeding depression / little hybrid vigour ;\n2 low / decreased, genetic, diversity / variation or small gene pool ;\n3 disadvantageous recessive alleles (more likely to be) expressed ;\n4 infertility / low disease resistance / reduced fitness ;\n5 low / decreased, ability to adapt or high / increased, risk of extinction ;\n6 AVP ;\n© Cambridge University Press & Assessment 2025 Page 14 of 17", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p14.png" ] }, { "id": "9700-2025-on-44-q08", "question_id": "9700-2025-on-44-q08", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 8, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 8, "status": "available", "reason": null, "text": "8(a) any four from: 4\n1 Ca2+ act as second messenger ;\n2 causes (K+) channel proteins to open ;\n3 X = potassium ions / K+ (that leave the cell) ;\n4 water potential of cell increases / water leaves cell by osmosis ;\n5 (guard) cell, becomes flaccid / loses turgidity ;\n\n8(b) any four from: 4\n1 (stomata) open to take up carbon dioxide for photosynthesis ;\n2 (stomata) close to prevent, transpiration / (excessive) water loss ;\n3 e.g. conditions when stomata close ;\n4 (water homeostasis needed to) maintain turgidity of cells / supply water for reactions ;\n5 ref. to daily rhythm or open during, day / light, and close, at night / at low light intensity / in the dark ;\n6 AVP ;\nQuestion Answer Marks", "source_pages": [ 15 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p15.png" ] }, { "id": "9700-2025-on-44-q09", "question_id": "9700-2025-on-44-q09", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "9(a) 1 NAD ; 2\n2 coenzyme A ;\n\n9(b) any three from: 3\n1 enzyme activity decreases over time at both concentrations (of hydrogen peroxide) ;\n2 activity decreases, more / faster / at a greater rate, at high(er) H O concentration\n2 2\nor\nenzyme less active with, with high(er) H O concentration ;\n2 2\n3 paired data quote ;\n4 H O , acts as an inhibitor / inhibits enzyme activity ;\n2 2\n© Cambridge University Press & Assessment 2025 Page 15 of 17\n\n9(c) any four from: 4\n1 energy is used to pump, protons / H+, into intermembrane space ;\n2 proton gradient (formed) ;\n3 protons diffuse through ATP synthase ;\n4 ATP produced from ADP and Pi ;\n5 oxygen accepts electrons to form water ;\n6 ref. to chemiosmosis ;\n\n9(d) any three from: 3\n1 respiration in anaerobic conditions ;\n2 produces lactate ;\n3 need oxygen, to oxidise lactic acid to CO and H O /\n2 2\nfor breakdown of lactic acid in Krebs cycle plus oxidative phosphorylation /\n(for ETC) to make extra ATP ;\n4 ATP used for lactate → glucose / glycogen ;\n5 idea of re-paying oxygen debt ;\n© Cambridge University Press & Assessment 2025 Page 16 of 17", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p15.png", "../answer-assets/9700_w25_ms_44-p16.png" ] }, { "id": "9700-2025-on-44-q10", "question_id": "9700-2025-on-44-q10", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 10, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 7, "status": "available", "reason": null, "text": "10(a) any three from: 3\ncyclic non-cyclic\n1 photosystem I (only) vs photosystems I and II ;\n2 electrons return to, same vs electrons do not return to ;\nphotosystem / PSI / P700 same photosystem\n3 ATP made vs ATP and reduced NADP ;\nmade\n4 no photolysis vs photolysis ;\n5 no oxygen produced vs oxygen produced ;\n\n10(b) 1 carbon dioxide ; 4\n2 Rubisco ;\n3 NADPH ;\n4 glucose / hexose / starch / cellulose /\nglycerol / fatty acids / lipids /\namino acids / proteins ;\n© Cambridge University Press & Assessment 2025 Page 17 of 17", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_44.pdf?download=true", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_44-p17.png" ] }, { "id": "9700-2025-on-51-q01", "question_id": "9700-2025-on-51-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 18, "status": "available", "reason": null, "text": "1(a) any one from: 1\n(presence of) juglone (with a concentration of 1.0  10-3 moldm-3)\nand\ncontrol (treatment) / absence of juglone ;\nconcentration, of juglone ;\n\n1(b)(i) 5 cm3 of (original / 0.1 mol dm-3) juglone (solution) ; 2\n495 cm3 of the (mixture of) solvents ;\n\n1(b)(ii) any one from: 1\nuse, syringe / graduated pipette / micropipette / burette ;\nuse, volumetric flask ;\nuse larger (stated) volumes (of both juglone and mixture of solvents) ;\n\n1(c)(i) 1 (mixture of) solvents / solution, with no juglone ; 2\n2 idea that to show that any effects observed (on the, germination / growth, of seeds) are a result of juglone ;\n© Cambridge University Press & Assessment 2025 Page 8 of 12\n\n1(c)(ii) any seven from: 7\n1 method for standardising the exposure of the seeds to juglone ;\n2 ref. to use, same / stated, (cucumber) seeds ;\n3 method to maintain a, constant / stated, temperature ;\n4 method to maintain a, constant / stated, light intensity ;\n5 ref. to standardise another key variable ;\n6 idea of reapply juglone (to seedlings) after germination ;\n7 count / note / record / AW, number of seeds planted and count number of seeds that germinate, after a, set / stated,\ntime ;\n8 method for measuring growth at 10 days (after the appearance of the seedling above the soil) ;\n9 for juglone solution and control treatment, use a large number of seeds and calculate the mean (growth) for\neach group ;\n10 safety comment with hazard and risk and precaution ;\nhazard risk precaution\njuglone irritant / toxin / allergy gloves / mask / PPE\nsolvents irritant / toxin / allergy gloves / mask / PPE\ncucumber irritant / allergy gloves / mask / PPE\nseeds / plants\nsoil biohazard / pathogens / gloves / mask / PPE\nallergy / irritant\n© Cambridge University Press & Assessment 2025 Page 9 of 12\n\n1(d)(i) any two from: 2\n1 data is continuous ;\n2 comparing means (from the two groups) ;\n3 data is (from populations that are) normally distributed ;\n4 standard deviations (approximately) the same (between the two groups) ;\n\n1(d)(ii) any three from: 3\n1 (the critical value at 18 d.f. and p = 0.05 is) 2.101 ;\n2 calculated value of t / 2.090, is less than, critical value / 2.101 (at p = 0.05) ; ora\n3 null hypothesis is accepted (at p = 0.05) ;\n4 there is no significant difference (at p = 0.05) ;\n© Cambridge University Press & Assessment 2025 Page 10 of 12", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_51-p08.png", "../answer-assets/9700_w25_ms_51-p09.png", "../answer-assets/9700_w25_ms_51-p10.png" ] }, { "id": "9700-2025-on-51-q02", "question_id": "9700-2025-on-51-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 12, "status": "available", "reason": null, "text": "2(a) any two from: 2\n1 (initial) volume / population / number, of bacteria (in bacterial suspensions)\nor\nvolume of (bacterial) suspension\nor\n(original) optical density of (bacterial) suspensions ;\n2 volume of nitrite (ion solution) ;\n3 concentration / volume, of nutrient broth ;\n\n2(b)(i) (species of bacterium:) nominal ; 2\n(lowest nitrite concentration:) continuous ;\n\n2(b)(ii) 1 correct reading of values from Figure 2.1 3\n(Salmonella enteritidis =) 0.7 and (Salmonella typhimurium =) 5 ;\n2 correct working ;\n3 correct value for percentage difference ;\n614 (%) / 86 (%)\n\n2(b)(iii) (most affected =) Yersinia enterocolitica 1\n(least affected =) Salmonella typhimurium ;\n© Cambridge University Press & Assessment 2025 Page 11 of 12\n\n2(c) any four from: 4\n1 idea that investigation, not carried out in a person / carried out in a laboratory ;\n2 idea that investigation only carried out for 24 hours / no information about longer term effects ;\n3 idea that experiment, only used 5 species of (pathogenic) bacteria / did not use other bacteria ;\n4 pH in the, digestive system / stomach / intestines / AW, is not 4.8 / is different ;\n5 idea that nitrites may, kill / reduce growth / AW, of / beneficial / AW, bacteria (in the digestive system) ;\n6 nitrites could, cause side effects / be toxic / AW (in humans) ;\n7 no evidence of control experiment ;\n8 no statistical, test / analysis ;\n9 idea that (bacterial) population sizes may not have decreased (as only measured when no bacterial population growth\noccurred) ;\n© Cambridge University Press & Assessment 2025 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_51.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_51-p11.png", "../answer-assets/9700_w25_ms_51-p12.png" ] }, { "id": "9700-2025-on-52-q01", "question_id": "9700-2025-on-52-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 18, "status": "available", "reason": null, "text": "1(a)(i) independent: sucrose concentration ; 2\ndependent: width of stomata ;\n\n1(a)(ii) 2.5 and 17.5 (to produce a 2.5% sucrose solution) ; 2\n5 and 15 (to produce a 5.0% sucrose solution) ;\n\n1(a)(iii) 1 use all sucrose concentrations ; 5\nany four from:\n2 leave the epidermis in sucrose solution for the same time ;\n3 calibrate, the eyepiece graticule ;\n4 measure the width of the stomata ;\n5 measure stomata at their widest point ;\n6 idea of (measuring) 3 or more (different) stomata (for any single concentration) ;\n7 calculate the mean (width of the stomata) for any single concentration ;\n8 named hazard and risk and precaution ;\nhazard risk Precaution\nplant material allergy / irritant gloves / eye protection / PPE\nslides / cover slip cuts ensure it is not placed near edge of bench\nor\nuse glass bin / dustpan and brush / AW, for disposal.\nscalpel / knife cuts cut away from hand / cut onto board / tile / AW\n© Cambridge University Press & Assessment 2025 Page 8 of 12\n\n1(a)(iv) predict: 2\n(as sucrose concentration increases width of stomata) decreases ;\nExplain (must match the prediction):\n(as the sucrose concentration increases) water leaves the guard cells, by, osmosis / down a water potential gradient / from\nhigh to low water potential ;\nor\n(as the sucrose concentration increases) less water enters the guard cells, by osmosis / down a water potential gradient\nfrom high to low water potential ;\n\n1(b)(i) 1 stomatal density = 367 (mm-2) ; 4\nAny three of:\n2 (number of stomata) = 13 ;\n3 diameter of picture = 8.5 cm / 85 mm\nor\nradius of picture = 4.25 cm / 42.5 mm\nor\nlength of scale bar / 40 µm = 1.6 cm / 16 mm ;\n4 show stomatal density calculation ;\n5 show magnification (calculation) ;\n\n1(b)(ii) use more than one, field of view / slide / epidermis / (plantain lily) leaf ; 1\n© Cambridge University Press & Assessment 2025 Page 9 of 12\n\n1(b)(iii) 2\n1 Environmental condition ; 2 Explanation ;\ndry / arid / less water So less water lost / less transpiration\nlow humidity\nhigh temperature / warm / hot\nwindy / high wind speed\nQuestion Answer Marks", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_52-p08.png", "../answer-assets/9700_w25_ms_52-p09.png", "../answer-assets/9700_w25_ms_52-p10.png" ] }, { "id": "9700-2025-on-52-q02", "question_id": "9700-2025-on-52-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 7, "status": "available", "reason": null, "text": "2(a) (0 µmoldm-3 ABA = ) 1.85 and (400 µmoldm-3 ABA = ) 1.35 ; 2\n27 ;\n\n2(b) any two from: 2\n1 as ABA concentration increases, transpiration rate decreases, except at (ABA concentration of) 50 ;\n2 error bars for (ABA concs) 10 or 50 overlap with (ABA conc) 0 so, there is no significant difference\n(in transpiration rates)\nor\nerror bars for (ABA concs) 100 overlap with (ABA conc) 10 so, there is no significant difference\n(in transpiration rates)\nor\nerror bars for (ABA concs) 100 overlap with (ABA conc) 400 so, there is no significant difference\n(in transpiration rates) ;\n3 error bars for (ABA concs) 100 or 400 do not overlap with (ABA conc) 0 so, there maybe, a significant difference\n(in transpiration rates) ;\n© Cambridge University Press & Assessment 2025 Page 10 of 12\n\n2(c) any three from: 3\n1 data for the non-mutant variety ;\n2 need to carry out a statistical test ;\n3 & 4 ref. to a named standardised variable ; ;\n5 ref. to knowing that water is lost from a named part of plant (somewhere other than the stomata) ;\nQuestion Answer Marks", "source_pages": [ 10, 11 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_52-p10.png", "../answer-assets/9700_w25_ms_52-p11.png" ] }, { "id": "9700-2025-on-52-q03", "question_id": "9700-2025-on-52-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 5, "status": "available", "reason": null, "text": "3(a) any two from: 2\n1 age of seeds ;\n2 all awns are straight / all awns are twisted at the start ;\n3 temperature ;\n4 light intensity / carry out in a dark room ;\n5 time seeds left in the different humidities (before measuring them) ;\n6 type / thickness / absorbency / size / dimensions / area, of filter paper ;\n© Cambridge University Press & Assessment 2025 Page 11 of 12\n\n3(b) any three from: 3\n1 add different volumes of water (to the filter paper) ;\n2 leave one (filter paper) with no water ;\n3 ref. to measuring appearance of awn ;\n4 idea of repeat, for each humidity ;\n© Cambridge University Press & Assessment 2025 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_52.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_52-p11.png", "../answer-assets/9700_w25_ms_52-p12.png" ] }, { "id": "9700-2025-on-53-q01", "question_id": "9700-2025-on-53-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 18, "status": "available", "reason": null, "text": "1(a) any one from: 1\n(presence of) juglone (with a concentration of 1.0  10-3 moldm-3)\nand\ncontrol (treatment) / absence of juglone ;\nconcentration, of juglone ;\n\n1(b)(i) 5 cm3 of (original / 0.1 mol dm-3) juglone (solution) ; 2\n495 cm3 of the (mixture of) solvents ;\n\n1(b)(ii) any one from: 1\nuse, syringe / graduated pipette / micropipette / burette ;\nuse, volumetric flask ;\nuse larger (stated) volumes (of both juglone and mixture of solvents) ;\n\n1(c)(i) 1 (mixture of) solvents / solution, with no juglone ; 2\n2 idea that to show that any effects observed (on the, germination / growth, of seeds) are a result of juglone ;\n© Cambridge University Press & Assessment 2025 Page 8 of 12\n\n1(c)(ii) any seven from: 7\n1 method for standardising the exposure of the seeds to juglone ;\n2 ref. to use, same / stated, (cucumber) seeds ;\n3 method to maintain a, constant / stated, temperature ;\n4 method to maintain a, constant / stated, light intensity ;\n5 ref. to standardise another key variable ;\n6 idea of reapply juglone (to seedlings) after germination ;\n7 count / note / record / AW, number of seeds planted and count number of seeds that germinate, after a, set / stated,\ntime ;\n8 method for measuring growth at 10 days (after the appearance of the seedling above the soil) ;\n9 for juglone solution and control treatment, use a large number of seeds and calculate the mean (growth) for\neach group ;\n10 safety comment with hazard and risk and precaution ;\nhazard risk precaution\njuglone irritant / toxin / allergy gloves / mask / PPE\nsolvents irritant / toxin / allergy gloves / mask / PPE\ncucumber irritant / allergy gloves / mask / PPE\nseeds / plants\nsoil biohazard / pathogens / gloves / mask / PPE\nallergy / irritant\n© Cambridge University Press & Assessment 2025 Page 9 of 12\n\n1(d)(i) any two from: 2\n1 data is continuous ;\n2 comparing means (from the two groups) ;\n3 data is (from populations that are) normally distributed ;\n4 standard deviations (approximately) the same (between the two groups) ;\n\n1(d)(ii) any three from: 3\n1 (the critical value at 18 d.f. and p = 0.05 is) 2.101 ;\n2 calculated value of t / 2.090, is less than, critical value / 2.101 (at p = 0.05) ; ora\n3 null hypothesis is accepted (at p = 0.05) ;\n4 there is no significant difference (at p = 0.05) ;\n© Cambridge University Press & Assessment 2025 Page 10 of 12", "source_pages": [ 8, 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_53-p08.png", "../answer-assets/9700_w25_ms_53-p09.png", "../answer-assets/9700_w25_ms_53-p10.png" ] }, { "id": "9700-2025-on-53-q02", "question_id": "9700-2025-on-53-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 12, "status": "available", "reason": null, "text": "2(a) any two from: 2\n1 (initial) volume / population / number, of bacteria (in bacterial suspensions)\nor\nvolume of (bacterial) suspension\nor\n(original) optical density of (bacterial) suspensions ;\n2 volume of nitrite (ion solution) ;\n3 concentration / volume, of nutrient broth ;\n\n2(b)(i) (species of bacterium:) nominal ; 2\n(lowest nitrite concentration:) continuous ;\n\n2(b)(ii) 1 correct reading of values from Figure 2.1 3\n(Salmonella enteritidis =) 0.7 and (Salmonella typhimurium =) 5 ;\n2 correct working ;\n3 correct value for percentage difference ;\n614 (%) / 86 (%)\n\n2(b)(iii) (most affected =) Yersinia enterocolitica 1\n(least affected =) Salmonella typhimurium ;\n© Cambridge University Press & Assessment 2025 Page 11 of 12\n\n2(c) any four from: 4\n1 idea that investigation, not carried out in a person / carried out in a laboratory ;\n2 idea that investigation only carried out for 24 hours / no information about longer term effects ;\n3 idea that experiment, only used 5 species of (pathogenic) bacteria / did not use other bacteria ;\n4 pH in the, digestive system / stomach / intestines / AW, is not 4.8 / is different ;\n5 idea that nitrites may, kill / reduce growth / AW, of / beneficial / AW, bacteria (in the digestive system) ;\n6 nitrites could, cause side effects / be toxic / AW (in humans) ;\n7 no evidence of control experiment ;\n8 no statistical, test / analysis ;\n9 idea that (bacterial) population sizes may not have decreased (as only measured when no bacterial population growth\noccurred) ;\n© Cambridge University Press & Assessment 2025 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_53.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_53-p11.png", "../answer-assets/9700_w25_ms_53-p12.png" ] }, { "id": "9700-2025-on-54-q01", "question_id": "9700-2025-on-54-q01", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "54", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "1(a) any sensible concentrations ; 2\ncorresponding volumes of distilled water and sucrose;\n\n1(b) any seven from: 7\n1 same / stated, variety / age / AW, of beetroots ;\n2 remove the outer skin (of the beetroot) / AW ;\n3 same / stated, dimensions / AW, of (beetroot) block / AW ;\n4 ref. to apparatus for obtaining same size of (beetroot) blocks ;\n5 for each sucrose concentration, place (beetroot) block in a suitable container and submerge / AW (in sucrose solution);\n6 (for each sucrose concentration) measure the initial mass and the final mass ;\n7 (measure final mass) after a (suitable) stated time ;\n8 method to remove excess liquid from beetroot (before measuring final mass) ;\n9 use at least three different (beetroot) blocks and calculate a mean, for each sucrose concentration ;\n10 safety comment with named hazard and risk and precaution ;\nhazard risk precaution\nbeetroot allergy / irritant gloves / mask / PPE\nknife / scalpel / cork borer / AW cut cut away from the hand / cut onto a, board / tile / AW\n\n1(c)(i) 1 appropriate axis labels and units ; 2\n2 sketch shows decreasing line crossing x-axis ;\n© Cambridge University Press & Assessment 2025 Page 8 of 12\n\n1(c)(ii) (identify the) x-axis intercept point 1\nor\n(identify the point on the x-axis where the mean) percentage change in mass is zero ;\n\n1(c)(iii) rinse (beetroot) blocks (after cutting / before adding to sucrose solution) ; 1\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_54.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_54-p08.png", "../answer-assets/9700_w25_ms_54-p09.png" ] }, { "id": "9700-2025-on-54-q02", "question_id": "9700-2025-on-54-q02", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "54", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a) method for measuring a curved claw (on the image) ; 1\n\n2(b)(i) any one from: 1\ncolour of disc ;\nmaterial of disc ;\ntype of particle ;\n\n2(b)(ii) (level of) roughness 1\nor\n(mean) particle diameter (on disc) ;\n\n2(b)(iii) 24 or 25 (feeding visits) ; 1\n\n2(b)(iv) any two from: 2\n1 as the particle diameter increases, (percentage of feeding visits when buff-tailed bumblebees) gripped (on to the disc)\nincreases ; ora\n2 at 30 µm and 53 µm / over 30 µm, there is no, difference / change / increase / AW (in percentage of feeding visits when\nbuff-tailed bumblebees gripped on to the disc) ;\n3 3. at 5 µm, (buff-tailed bumblebees) only hover ;\n© Cambridge University Press & Assessment 2025 Page 9 of 12\n\n2(c)(i) Table 2.2 completed 2\nmean particle rank of mean percentage of feeding rank of percentage of Difference in D2\ndiameter on the particle diameter visits when the buff- feeding visits when the rank, D\ndisc / μm on the disc tailed bumblebees buff-tailed bumblebees\ngripped on to the disc gripped on to the disc\n5 1 0 1 0 0\n9 2 4 2 0 0\n12 3 16 3 0 0\n16 4 79 4 0 0\n30 5 99 5.5 0.5 0.25\n53 6 99 5.5 ; 0.5 0.25\nD2 = 0.5 ;\n\n2(c)(ii) (r =) 0.99 / 0.986 ; 1\ns\n\n2(c)(iii) 0.99 / calculated value for r , is greater than 0.83 ; 1\ns\n© Cambridge University Press & Assessment 2025 Page 10 of 12", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_54.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_54-p09.png", "../answer-assets/9700_w25_ms_54-p10.png" ] }, { "id": "9700-2025-on-54-q03", "question_id": "9700-2025-on-54-q03", "subject": "9700", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "54", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 7, "status": "available", "reason": null, "text": "3(a)(i) Table 3.1 completed correctly ; 1\ntype of fruit mean of\nsamples\napple 17 / 16.7\norange 33 / 33.3\npineapple 43 / 43.3\ngrapes 14 / 14.3\n\n3(a)(ii) Table 3.2 completed correctly ; 2\ntype of variable type of data\ntype of fruit categoric / qualitative nominal\nvolume of juice extracted quantitative continuous\n© Cambridge University Press & Assessment 2025 Page 11 of 12\n\n3(a)(iii) any two from: 2\n1 standardise, (total) mass / volume, of fruit used\nor\nstandardise number of pieces of fruit used\nor\nstandardise, dimensions / mass / volume / size / surface area / AW, of (each fruit) piece ;\n2 use same, age / ripeness of each fruit ;\n3 use a more accurate method to measuring the volume (of pectinase)\nor\nuse a more accurate method to measure the volume (of juice) ;\n4 replace pectinase with, (distilled) water / denatured pectinase / boiled pectinase / AW ;\n\n3(b) any two from: 2\n1 idea that the volume of juice may not be correlated with the quantity of pectin ;\n2 age / ripeness, of fruit affects quantity of juice ;\n3 idea of cell walls of different fruits have different compositions ;\n© Cambridge University Press & Assessment 2025 Page 12 of 12", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2025-Oct-Nov/ms/9700_w25_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2025-oct-nov/9700_w25_ms_54.pdf?download=true", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_w25_ms_54-p11.png", "../answer-assets/9700_w25_ms_54-p12.png" ] }, { "id": "9700-2026-m-42-q01", "question_id": "9700-2026-m-42-q01", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 10, "status": "available", "reason": null, "text": "1(a) any three from: 3\n1 habitat loss ;\n2 climate change ;\n3 increased hunting ;\n4 increased competition / lack of food ;\n5 increased predation ;\n6 new disease ; ignore disease unqualified\n7 effects of pesticides / fertilisers / pollution ;\n\n1(b) any three from: 3\n1 temperature, warmer than 25 °C / colder than 17 °C ;\n2 dry environment ;\n3 use, fungicides / antifungals / disinfectants / biological control ;\n4 prevent entry of / remove, infected / carrier, frogs ;\n5 monitoring for, fungus / disease ; A before or after re-introduction\n© Cambridge University Press & Assessment 2026 Page 8 of 25\n\n1(c) any four from: 4\n1 eukaryotic / have nucleus ;\n2 no, chlorophyll / chloroplasts ;\n3 heterotrophic / saprophytic / saprotrophic / parasitic / described ;\n4 cell walls made of, chitin / mannoproteins / glucans ;\n5 reproduce by spores ;\n6 hyphae / mycelium ;\n7 multinucleate / AW ;\n8 either multicellular or unicellular ;\n© Cambridge University Press & Assessment 2026 Page 9 of 25", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p08.png", "../answer-assets/9700_m26_ms_42-p09.png" ] }, { "id": "9700-2026-m-42-q02", "question_id": "9700-2026-m-42-q02", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 7, "status": "available", "reason": null, "text": "2(a)(i) range of values / range of phenotypes / intermediates ; 1\nA do not fall into distinct groups\n\n2(a)(ii) any three from: 3\n1 environment has a large effect ;\n2 example of environmental factor relevant to body mass ;\ne.g., diet, disease (loss of appetite, use of calories), exercise\n3 interaction of environmental factors with genes\nor\nV = V + V ;\nP G E\n4 (additive / combined, effect of), many genes / polygenes ;\n\n2(b)(i) any two from: 2\n1 (mutant POMC allele) causes increase in body mass ;\n2 comparative data quote (in support of mp1) ;\n3 heterozygous has intermediate, phenotype / mass\nor\none mutant allele has an effect ;\n4 overlap of, error / SD, bars between homozygous normal and heterozygous\nor\nnon-overlap of, error / SD, bars between homozygous mutant and, heterozygous / homozygous normal ;\n5 AVP ; e.g. variation in body mass within groups shows other factors also contribute / AW\n\n2(b)(ii) eat more / do less exercise / AW ; 1\n© Cambridge University Press & Assessment 2026 Page 10 of 25", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p10.png" ] }, { "id": "9700-2026-m-42-q03", "question_id": "9700-2026-m-42-q03", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 12, "status": "available", "reason": null, "text": "3(a) HTT / huntingtin ; A IT15 2\nhuntingtin ;\n\n3(b)(i) any one from: 1\n1 (close) family history (of Huntington’s) ;\n2 adults that have (early) symptoms of Huntington’s ;\n\n3(b)(ii) any two from: 2\n1 adult-onset disease / symptoms generally occur later in life ;\n2 adults can make lifestyle choices ;\ne.g. whether or not to have children\n3 implications of positive result ;\ne.g. at-risk parent may not have taken test\ne.g. wait to see if parent has Huntington’s\n4 psychological impact / children not able to give (informed) consent / AW ; ora\n\n3(c) A DNA fragments or bands for alleles throughout 4\n1 adult A has no alleles with more than 35 (CAG) repeats ; ora\n2 adult B has one allele between 35 and 40 (CAG) repeats ;\n3 adult C and adult D have one allele with more than 40 (CAG) repeats ;\n4 adult D has more (CAG) repeats than adult C ;\n© Cambridge University Press & Assessment 2026 Page 11 of 25\n\n3(d) any three from: 3\n1 Huntington’s disease is (autosomal) dominant ;\n2 addition of normal allele only corrects recessive disorders\nor\ndominant allele cannot be, masked / switched off ;\n3 gene therapy does not remove the, mutated / dominant, allele ;\n4 not able to replace, nerve / brain cells ;\n5 correct type of stem cells may not be available ; A correct ref. to viruses\n© Cambridge University Press & Assessment 2026 Page 12 of 25", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p11.png", "../answer-assets/9700_m26_ms_42-p12.png" ] }, { "id": "9700-2026-m-42-q04", "question_id": "9700-2026-m-42-q04", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 12, "status": "available", "reason": null, "text": "4(a) any three from: 3\n1 formation of new species from, pre-existing species / (common) ancestor ;\nA description\n2 over, time / generations ;\n3 mutations / changes in gene pools / changes in allele frequencies ;\n4 change in, characteristics / phenotypes ;\n5 natural selection ;\n6 AVP ; e.g. genetic drift / allopatric / sympatric\n\n4(b)(i) A names for numbers throughout 3\nany three from:\nmax two for similarities in both figures:\n1 diverged into two groups, at the same time / 67 million years ago\n2 idea that group 1 is on a different (evolutionary) branch to group(s), 3 / 4 ;\n3 idea that group 3 and group 4 diverge more recently / AW\nor\ngroup 3 and group 4 on the same (evolutionary) branch ;\ndifferences:\n4 first divergence resulted in, group 1, in, Figure 4.2\nbut in, Figure 4.1, group 1, formed later ;\n5 group 2 are closely related to group, 3 / 4, in Figure 4.2\nor\ngroup 2 are closely related to group 1 in, Figure 4.1 ;\n© Cambridge University Press & Assessment 2026 Page 13 of 25\n\n4(b)(ii) any two from: 2\n1 compare, base / nucleotide, sequences (of DNA)\nor\nidentify, similarities / differences, in, base / nucleotide, sequences (of DNA) ;\n2 more similarities means species, are more closely related / have a more recent common ancestor ;\n3 ref. to arrange in groups of shared mutations ;\n4 ref. bioinformatics ; A description\n\n4(b)(iii) data from more species ; 1\n\n4(c) any three from: 3\n1 less genetic, diversity / variation ;\n2 alleles not exchanged between non-sister chromatids ;\n3 allele combinations remain the same (as parents) ; ora\n4 linkage groups not broken / AW ; ora\n© Cambridge University Press & Assessment 2026 Page 14 of 25", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p13.png", "../answer-assets/9700_m26_ms_42-p14.png" ] }, { "id": "9700-2026-m-42-q05", "question_id": "9700-2026-m-42-q05", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "5(a) ALLOW one mark if only letters stated in correct order 5\nTable 7.1\npart of sarcomere description\nH zone / band ; only myosin present\nA band ; actin and myosin present\nI band ; only actin present\nM line ; attachment for myosin\nZ disc / line ; attachment for actin\n© Cambridge University Press & Assessment 2026 Page 15 of 25\n\n5(b) any four from: 4\n1 fewer calcium ions absorbed by muscle (fibres) from the blood ;\n2 fewer calcium ions released by sarcoplasmic reticulum ;\n3 fewer calcium ions bind to troponin ;\n4 fewer, myosin head binding sites exposed on actin / myosin heads bind to actin / cross bridges formed ;\n5 weaker / fewer / slower, power strokes ; A described\n6 weaker / fewer / slower, muscle contraction / sarcomere shortening ;\n7 AVP ; e.g. fewer calcium ions so less transmission at neuromuscular junction / release of neurotransmitter\n© Cambridge University Press & Assessment 2026 Page 16 of 25", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p15.png", "../answer-assets/9700_m26_ms_42-p16.png" ] }, { "id": "9700-2026-m-42-q06", "question_id": "9700-2026-m-42-q06", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 8, "status": "available", "reason": null, "text": "6(a) 3\nname type name of function of\nof gene of gene protein produced protein produced\nbinds to operator\nlacI regulatory ; repressor protein to prevent RNA polymerase\nbinding to promoter\nhydrolyses / breaks\ndown / converts, lactose\nto glucose and galactose ;\nlacZ structural -galactosidase\nA converts lactose\nto allolactose\nmembrane transport protein\nlacY ; structural lactose permease to increase cellular uptake\nof lactose\nacetylates galactoside\nlacA structural transacetylase sugar residues\nto detoxify the cell\n© Cambridge University Press & Assessment 2026 Page 17 of 25\n\n6(b) ora for animal insulin 5\nany five from:\n1 large scale supply / supply can match demand ;\n2 no / less, chance of immune / allergic response\nor\nfewer side effects ;\n3 fast to act / smaller dose needed ;\n4 not / less, likely for (insulin) tolerance to occur ;\n5 no / less, risk of, infection / disease ;\n6 no / fewer, ethical / religious, considerations\nor\nsuitable for, vegans / vegetarians ;\n7 cheaper to produce / can control time of production / easier to purify ;\n© Cambridge University Press & Assessment 2026 Page 18 of 25", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p17.png", "../answer-assets/9700_m26_ms_42-p18.png" ] }, { "id": "9700-2026-m-42-q07", "question_id": "9700-2026-m-42-q07", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 13, "status": "available", "reason": null, "text": "7(a) A – podocyte ; 3\nB – basement membrane ;\nC – endothelial (cell) ;\n\n7(b) any three from: 3\n1 decreased, (glomerular) blood pressure / hydrostatic pressure ;\n2 dehydration / reduced water potential of blood / loss of blood / heart failure ;\n3 (named) kidney disease ; A diabetes\n4 damage to, Bowman’s capsule / basement membrane / glomerulus / arterioles ;\n5 ref. to, drugs / hormones, qualified ; A named or action described e.g. ADH / beta blockers / diuretics\n© Cambridge University Press & Assessment 2026 Page 19 of 25\n\n7(c) any seven from: 7\n1 maintain constant internal environment / AW ; e.g. within narrow limits\n2 despite changes in the, internal / external, environment ;\nmax two from:\n3 named factor ; e.g. temperature / water potential / blood glucose concentration\n4 changes in factor / stimulus, detected by (named) receptor ;\n5 ref. to central control decision / AW ; e.g. ref. to, brain / CNS / hypothalamus\n6 response carried out by effector ;\n7 named effector ; e.g. muscle / gland\n8 corrective action ; A correct example\n9 factor returns to, set point / norm ;\n10 negative feedback ;\n© Cambridge University Press & Assessment 2026 Page 20 of 25", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p19.png", "../answer-assets/9700_m26_ms_42-p20.png" ] }, { "id": "9700-2026-m-42-q08", "question_id": "9700-2026-m-42-q08", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 8, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 7, "status": "available", "reason": null, "text": "8(a) A = active transport ; 3\nB = anabolism / anabolic (reaction) / polymerisation / bond formation / condensation (reaction) ;\nC = photoactivation / light activation / photo-ionisation ;\n\n8(b) 1 protons diffuse through ATP synth(et)ase ; 2\n2 protons are pumped into intermembrane space / proton gradient formed / ADP + inorganic phosphate ;\n\n8(c) 222.4 ; ;\nallow 1 mark for:\n© Cambridge University Press & Assessment 2026 Page 21 of 25\n 3\n1\n7\n7\n. 8\n. 0\n\n 1 0 0\n2\nor\nnot to one decimal place", "source_pages": [ 21 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p21.png" ] }, { "id": "9700-2026-m-42-q09", "question_id": "9700-2026-m-42-q09", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "9(a) 1 oxygen concentration decreases (with time) ; 4\n2 oxygen concentration becomes constant when nitric oxide is added ;\n3 oxygen concentration remains constant for longer with each addition ;\nmax three for explanation:\n4 (nitric oxide may) prevent oxygen uptake ;\n5 (nitric oxide may) inhibit, pyruvate entering mitochondrion / the link reaction / Krebs cycle / ETC / oxidative\nphosphorylation ;\n6 so oxygen cannot act as final electron acceptor ;\n7 inhibits aerobic respiration ;\n8 effect of nitric oxide is temporary ;\n\n9(b) any four from: 4\nmp muscle yeast\n1 lactic acid / lactate ethanol ;\n2 one-step process two-step process ;\nA from equation A from equations\n3 reversible irreversible ;\n4 no carbon dioxide produced / carbon dioxide produced / ;\nno decarboxylation decarboxylation\n5 lactate dehydrogenase ethanol / alcohol, dehydrogenase ;\n© Cambridge University Press & Assessment 2026 Page 22 of 25\n\n9(c) any three from: 3\n1 aerenchyma in, stems / roots, to provide oxygen to submerged parts ;\n2 tall stems / fast growth of stems / greater internode growth, to hold, leaves / flowers, above water / exposed to air ;\n3 roots have, ethanol / alcohol, dehydrogenase\nor\nroots are tolerant to ethanol for, ethanol fermentation / anaerobic respiration ;\n4 ridges in submerged leaves to trap air ;\n© Cambridge University Press & Assessment 2026 Page 23 of 25", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p22.png", "../answer-assets/9700_m26_ms_42-p23.png" ] }, { "id": "9700-2026-m-42-q10", "question_id": "9700-2026-m-42-q10", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 10, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 11, "status": "available", "reason": null, "text": "10(a)(i) 2\ncrop number of number of stomatal\nstomata epidermal index / %\ncells\ncotton 6 32 ; 15.8\ngroundnut 9 36 20.0\nmung bean 5 12 29.4\nsorghum 8 20 28.6\ntomato 7 25 21.9 ;\n\n10(a)(ii) any two from: 2\n1 allows sufficient, carbon dioxide uptake / gaseous exchange ;\n2 reduces, transpiration / water loss ;\n3 stomata on lower surface less exposed to, high light intensity / wind ; ora\n4 allows more space for photosynthesis ;\n© Cambridge University Press & Assessment 2026 Page 24 of 25\n\n10(b) ignore references to respiration 4\nany four from:\ncarbon dioxide concentration is decreasing\n1 07:00 to 09:00, light intensity / temperature, is limiting factor ;\n2 as, light intensity / temperature, is increasing rate of photosynthesis is increasing ;\ncarbon dioxide concentration is, constant / low\n3 09:00 to 17:30 carbon dioxide concentration is limiting factor ;\n4 as rate of photosynthesis is high ;\ncarbon dioxide concentration is increasing\n5 17:30 to 22:00, light intensity / temperature, is limiting factor ;\n6 as, light intensity / temperature, is decreasing the rate of photosynthesis is decreasing ;\ncarbon dioxide concentration is, constant / high\n7 22:00–06:00 / 07:00, light intensity is limiting factor ;\n8 as, rate of photosynthesis is low / no photosynthesis ;\n\n10(c) 1 thylakoid (membrane) ; 3\n2 ATP and reduced NADP used to convert GP to TP ;\n3 ATP used in regeneration of RuBP ;\n© Cambridge University Press & Assessment 2026 Page 25 of 25", "source_pages": [ 24, 25 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_42-p24.png", "../answer-assets/9700_m26_ms_42-p25.png" ] }, { "id": "9700-2026-m-52-q01", "question_id": "9700-2026-m-52-q01", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 9, "status": "available", "reason": null, "text": "1(a) any two from: 2\n1 time of day ;\n2 (which) days (of week for exercise) ;\n3 speed / distance, of walking / running ;\n4 location / gradient / AW of, walking / running ;\n5 temperature ;\n\n1(b)(i) exercise (programme) ; 1\n\n1(b)(ii) any three from: 3\n1 (mean) difference in systolic blood pressure, increases / AW, after (the 12-week) exercise (programme) ; ora\n2 (mean) difference in diastolic blood pressure, was, negative / a decrease, before (the 12-week) exercise (programme)\nand\nis, positive / an increase, after (the 12-week exercise programme) ;\n3 systolic, blood pressure, increases / AW, after the walking test (before and after the 12-week exercise programme) ;\nora\n4 diastolic blood pressure, decreases / AW, after the walking test, before (the 12-week) exercise (programme)\nor\ndiastolic blood pressure, increases / AW, after the walking test, after (the 12-week) exercise (programme) ;\n5 paired data quote ;\n\n1(c)(i) 0.31 ; 1\n© Cambridge University Press & Assessment 2026 Page 8 of 13\n\n1(c)(ii) any two from: 2\n1 to calculate (95%) confidence intervals / CI\nor\nto plot error bars ;\n2 to test, whether the means (for the resting systolic blood pressures) are (significantly) different\nor\nto test, whether the, SE values / error bars / (95%) CI, overlap ;\n3 to get a measure of how close the, calculated / sample / AW, mean is likely to be to the, true / actual / AW, mean ;\n© Cambridge University Press & Assessment 2026 Page 9 of 13", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-52.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_52-p08.png", "../answer-assets/9700_m26_ms_52-p09.png" ] }, { "id": "9700-2026-m-52-q02", "question_id": "9700-2026-m-52-q02", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a) 0.26 (s) ; 1\n\n2(b)(i) 1 use of water as diluent ; 2\n2 12 cm3 of, 0.5% / stock, caffeine solution and 8 cm3 of water ;\n\n2(b)(ii) any seven from: 7\n1 use of a minimum of five stated caffeine concentrations ;\n2 use a stated volume of (each) caffeine solution ;\n3 use, a (light) microscope (to observe D. magna) ;\n4 use a method to maintain, same / stated, temperature\nor\nmethod to avoid overheating ;\n5 ref. to standardised variable relating to D. magna ;\n6 use a method to standardise, pH / oxygen concentration, of caffeine solutions ;\n7 method for, equilibration / acclimatisation, of D. magna ;\n8 at each (caffeine) concentration, count the number of cardiac cycles, in a, set / stated, time ;\n9 use of a method to ensure accurate counting ;\n10 at each (caffeine) concentration take at least three measurements ;\n11 idea of use, new / fresh / different, D. magna ;\n© Cambridge University Press & Assessment 2026 Page 10 of 13", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-52.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_52-p10.png" ] }, { "id": "9700-2026-m-52-q03", "question_id": "9700-2026-m-52-q03", "subject": "9700", "year": 2026, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "3(a) 1 correct axis labels: 2\npercentage / %, cover of, (water) hyacinth\nand\npercentage / %, cover of, malancha ;\n2 appropriately shaped line ;\nstraight line with upward trend\n\n3(b)(i) any suitable method of generating random numbers and matching to the (69) sampling locations ; 1\n\n3(b)(ii) 48 (%) ; ; 2\naward one mark for correct working if final answer incorrect or missing\n\n3(b)(iii) t-test 1\nand\nany one from:\nidea of comparing (the difference between two) means ;\ncontinuous data ;\nstandard deviations (for each treatment) are approximately the same ;\ndata (from populations that are) normally distributed ;\nfewer than 30 values (in each treatment) ;\n© Cambridge University Press & Assessment 2026 Page 11 of 13\n\n3(b)(iv) ref. to hazard and risk and precaution ; 1\nhazard risk precaution\nanimals allergy / bites / injury / medication / work in a group / travel\ninfection / disease with an expert / suitable PPE /\nfirst aid kit\n(plants) pollen allergy medication / mask\nenvironment woodland / falling injury / getting lost boots / hard hat / suitable\nbranches or trees / thorns / trip clothing / PPE / GPS / map / stay in a\nhazards / holes / mud group / use an\nexpert /\nwater / river / Armand bayou injury / drowning / hypothermia / swept boots / lifejacket / wetsuit / use an\naway (by current) expert / do not enter water / use a\nboat / use a rope\n(water-borne) pathogens / infection / disease / irritation (from PPE / wash hands\nparasites / pollution pollutants)\ntools / knife (to cut plants) injury cut away from, hand / body / other\npeople\n© Cambridge University Press & Assessment 2026 Page 12 of 13\n\n3(b)(v) any four from: 4\nin context of supports:\n1 (removal of malancha) reduces, (mean) area / abundance (of water hyacinth) in treatment 1 and 2 (compared to,\ncontrol / treatment 3)\nor\n(mean) area / abundance (of water hyacinth) is, lower / lowest / AW, in treatment 2, compared to, control / treatment 3 ;\n2 (95%) confidence intervals / CI / error bars, for treatment 2 and 3, do not overlap\nand\n(mean area / abundance of water hyacinth) is significantly different ;\nin context of limits support:\n3 (95%) confidence intervals / CI / error bars, for treatment 1 and 3, overlap\nand\n(mean area / abundance of water hyacinth) may not be significantly different ;\n4 investigation only carried out, once / at one time of year / over period of 8 weeks ;\n5 investigation only carried out at 12 locations ;\n6 no statistical test / should carry out a statistical test ;\n© Cambridge University Press & Assessment 2026 Page 13 of 13", "source_pages": [ 11, 12, 13 ], "source_pdf": "_source-pdfs/2026-March/ms/9700_m26_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-march/9700-biology-march-2026-mark-scheme-52.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_m26_ms_52-p11.png", "../answer-assets/9700_m26_ms_52-p12.png", "../answer-assets/9700_m26_ms_52-p13.png" ] }, { "id": "9700-2026-mj-41-q01", "question_id": "9700-2026-mj-41-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 8, "status": "available", "reason": null, "text": "1(a) 5\nstage location in the products of this stage\ncell\nIGNORE numbers\nglycolysis cytoplasm pyruvate\nALLOW NADH / red NAD / NAD red, for ‘reduced NAD’\nand\nIGNORE NADH+ / NADH\nATP 2\nand\nreduced NAD ;\nALLOW 1 mark if ‘matrix’ alone stated for both link and\nKrebs\nlink mitochondrial carbon dioxide\nALLOW 1 mark if ‘mitochondrion / mitochondria’ alone\nreaction matrix ; and\nstated for both\nacetyl co(enzyme) A\nALLOW 2 marks if ‘matrix’ alone stated for one but\nand\n‘mitochondrion / mitochondrial, matrix’ stated for the other\nreduced NAD ;\nKrebs mitochondrial carbon dioxide\nIGNORE oxaloacetate / water / GTP (for Krebs cycle)\ncycle matrix ; and\nATP\nALLOW FADH / red FAD / FAD red, for ‘reduced FAD’\nand 2\nIGNORE FADH\nreduced, NAD / FAD ;\n\n1(b) 1 hydrogen ion / H+ / proton ; 3 1 ALLOW ‘hydrogen / H’ alone\n2 thylakoid (membrane) ; 1 DO NOT ALLOW hydrogen molecule / H\n2\n3 facilitated diffusion ; 2 DO NOT ALLOW thylakoid space\n© Cambridge University Press & Assessment 2026 Page 8 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p08.png" ] }, { "id": "9700-2026-mj-41-q02", "question_id": "9700-2026-mj-41-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "2(a)(i) 1 initial receptors – osmoreceptors / hypothalamus ; 4 1 IGNORE osmoregulators\n2 coordination systems – endocrine / hormonal ; 2 IGNORE ADH\n3 final effectors – collecting, duct / tubule ; 3 IGNORE posterior pituitary gland\n3 CON other parts of nephron\n4 response – less urine produced / urine more\nconcentrated / less watery urine\nOR\nmore water, reabsorbed / taken up (into blood)\nOR\n(more) aquaporins added to membrane / membrane more\npermeable to water ;\n\n2(a)(ii) any two from: 2 IGNORE flaccid / turgid / plasmolysed\n1 if water potential, rises / high, cells, absorb 1 ALLOW if too much water in blood / blood dilute, for ‘high\nwater / swell / burst / lyse ; water potential’\n2 ALLOW if too little water in blood / blood concentrated, for\n2 if water potential, falls / low, cells, lose ‘low water potential’\nwater / shrink / crenate / shrivel ; ALLOW 1 mark for ‘so cells do not burst or shrink’ OR\n‘so cells do not gain water or lose water’ if mps 1 and 2 not\n3 water is a, solvent / medium / site, for, (named) reactions in given\ncells / metabolic reactions ; 3 e.g. water needed for hydrolysis (reactions) in cells\n4 AVP ; 4 e.g. control / maintain / important for, blood volume / blood\npressure / hydrostatic pressure / glomerular filtration\nref. prevent oedema\n\n2(b)(i) 180 (g) ; 1 calculation = 200  5  0.18\n© Cambridge University Press & Assessment 2026 Page 9 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(b)(ii) any four from: 4 IGNORE ultrafiltration\nDO NOT ALLOW basement membrane for mps 2, 3, 4 but\nECF after first error\nIf Na+ / sodium ion, not stated CON once then ECF\nin, proximal convoluted tubule / PCT: max 3 if PCT not stated\nCON if wrong part of nephron stated then ECF to max 3\nECF if cell not stated or implied (e.g. cytoplasm) for mps\n1 (glucose) reabsorbed / moves, into, blood / (peritubular) 2, 3 and 4 to max 3\ncapillary ;\n2 Na+ leaves (epithelial / tubule) cell by active transport (at 2 ALLOW using ATP / pumped / by pumps, for ‘active\nbasal / basolateral, membrane) ; transport’\n2 IGNORE transport protein\n3 glucose moves into cell by co-transport with Na+ (at 2 DO NOT ALLOW channel protein\nluminal membrane) ; 3 ALLOW through co-transporter protein for ‘by co-transport’\n4 glucose leaves cell by facilitated diffusion (at, 4 ECF from mp 2 if basement membrane repeated\nbasal / basolateral, membrane) ; 4 ALLOW diffuses through GLUT, proteins / channels, for\n‘facilitated diffusion’\n5 AVP ; 5 mp 2 establishes, Na+, diffusion gradient / concentration\ngradient e.g. secondary active transport\n© Cambridge University Press & Assessment 2026 Page 10 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p09.png", "../answer-assets/9700_s26_ms_41-p10.png" ] }, { "id": "9700-2026-mj-41-q03", "question_id": "9700-2026-mj-41-q03", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "3(a)(i) any four from: 4 IGNORE refs. to K+ ions\nALLOW mp 3 either in context of 3a or 3b but not twice\n(morning / opening / width increasing, context)\n1 width increases from 1 to 6.5 mm between 06.00 and 1 ALLOW 6.9 for 6.5 mm\n11.00 ;\n2 so (more) carbon dioxide can, enter / diffuse in ;\n3a high / rising, light intensity → high / more, photosynthesis\n;\n(afternoon / night / closing / width decreasing, context) 3b ALLOW in dark / at night / before 06.00, no\n3b low / decreasing, light intensity → low / less, photosynthesis\nphotosynthesis ; 4 ECF from mp 1 if peak time or width wrong\n4 width decreases from 6.5 to 3 mm between 11.00 and 5 CON prevent / stop, for ‘decrease’\n17.00 ;\n5 to, decrease / limit, transpiration / water loss ;\n\n3(a)(ii) any three from: 3\nALLOW ORA throughout\n1 K+ ions enter (guard) cell ; 1 CON stoma for ‘cell’\n2 water enters cell, by osmosis / down water potential 2 CON stoma for ‘cell’ but ECF from mp 1\ngradient → increase in volume / increase in turgor / cell 3 ALLOW opens for ‘widens’\nbecomes turgid ; 3 CON guard cell for ‘stoma’\n3 action in mp 1 or 2 causally linked to: widens 3 IGNORE statement of correlation\naperture / opens stoma(ta) ;\n\n3(b) any three from: 3 If answer is about when ABA will decrease (not answering\nquestion), CON 1 mark then apply ECF after first error\nABA concentration is more likely to increase when light If answer states that ABA rises when light intensity is\nintensity is decreasing because: increasing, CON 1 mark then apply ECF after first error\n1 ABA stops H+ moving, out of cell / into cell wall ;\n2 (ABA) causes Ca2+ ions to enter, cytoplasm / cell ;\n3 (ABA) causes K+ to leave (cytoplasm / cell) ; 3 IGNORE prevent K+ from entering\n4 (ABA) leads to, water leaving (cell) / guard cell becoming 4 DO NOT ALLOW guard cell closing\nflaccid / stomatal closing ; 4 IGNORE prevent stomata from opening\n© Cambridge University Press & Assessment 2026 Page 11 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p11.png" ] }, { "id": "9700-2026-mj-41-q04", "question_id": "9700-2026-mj-41-q04", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 7, "status": "available", "reason": null, "text": "4(a) any four from: 4\n1 (put) extract / sample / concentrate / pigments, on, 2 e.g. ethanol / acetone / petroleum ether +\npencil / base, line ; hexane / trichloromethane\n2 (named) solvent below, extract / line, and idea of time to 2 DO NOT ALLOW water\nrise / left till solvent rises / wait till solvent almost reaches top\n;\n5 ALLOW database / standard values\n3 remove paper (before solvent reaches end) and mark\nsolvent front ;\n4 (R =) distance pigment moved ÷ distance solvent moved ;\nf\n5 check / compare with, known / reference / published,\ndata / values ;\n\n4(b) any three from: 3 IGNORE colours throughout\n1 absorb light ; 1 ALLOW harvest / capture / trap, for ‘absorb’\n2 for, light dependent 2 IGNORE photolysis\n(stage) / photophosphorylation / photoactivation ; 2 CON if process described with error e.g. pigment passes\n3 absorb / use, more / different, wavelengths electrons to another pigment\nOR\n(different pigments have) different / extend, absorption\nspectra ; 4 e.g. chlorophyll a is, primary pigment / reaction centre and,\n4 AVP ; carotene / xanthophyll / chlorophyll b, are accessory\npigments e.g. (some pigments may) protect from excess\nlight\n© Cambridge University Press & Assessment 2026 Page 12 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 12 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p12.png" ] }, { "id": "9700-2026-mj-41-q05", "question_id": "9700-2026-mj-41-q05", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 15, "status": "available", "reason": null, "text": "5(a) Apply list rule for 4 responses 2\nCPCP NN two or three correct = 1 mark\nCPCY NN four correct = 2 marks\nCPCP Nn\nCPCY Nn ; ;\n\n5(b)(i) genotype: CBCY Nn ; 2 If both correct answers given but on wrong lines give 1\nmark\nphenotype: brown without stripes ; ECF for a phenotype that matches a wrong genotype\n\n5(b)(ii) any four from: 4 IGNORE crossing-over\n1 independent / random, assortment / orientation (of 1 ALLOW each pair of, chromosomes / alleles, lines\nchromosomes / alleles / genes) ; up / separates / segregates, independently of other pairs\n2 in metaphase I ; 2 ALLOW anaphase I if segregation described\n2 DO NOT ALLOW metaphase / anaphase, II\n3 ref. to genes, on separate chromosomes / not linked OR 3 CON ref. to breaking of linkage groups\nno linkage ;\n4 gametes / (daughter) cells / products of meiosis, are, 4 ALLOW get one of each pair of, chromosomes / alleles for\nhaploid / n ; ‘haploid / n’\n5 22 / 4, combinations, in dihybrid cross / with two genes OR 5 ALLOW digenic for ‘with two genes’\n(get) CB N CB n CY N CY n ;\n© Cambridge University Press & Assessment 2026 Page 13 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n5(b)(iii) any three from: 3\n1 CON sex linkage\n1 (autosomal) linkage OR genes were, linked / on same 2 ALLOW words e.g.\nchromosome ; alleles for (brown + stripes) and (yellow + no stripes),\ninherited together / linked / on same chromosome\n2 CB n, inherited together / linked / on same chromosome, 3 phenotypes were same as original parents\nand\nCY N, inherited together / linked / on same chromosome ;\n3 (offspring showed) parental phenotypes ;\n4 no, recombinants / crossing-over ;\n5 as, genes / loci, tightly linked / close together ;\n© Cambridge University Press & Assessment 2026 Page 14 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n5(c) any four from: 4 ALLOW ORA throughout\nECF after first CON to max 3\ne.g. in rough grass brown snails selected for, survive and\nreproduce = CON mp2 then gets mp 1 and mp 3.\n1 in woodland, non-yellow / brown / pink / unstriped, snails,\nare not seen / are camouflaged / are hidden / are not\neaten / survive OR\nin rough grass, yellow / striped, snails, are not seen / are\ncamouflaged / are hidden / are not eaten / survive ;\n2 ORA non-yellow / brown / pink / unstriped, snails selected\n2 in woodland, non-yellow / brown / pink / unstriped, snails against in rough grass\nhave a selective advantage / are selected for OR\nOR yellow / striped, snails selected against in woodland\nin rough grass, yellow / striped, snails have a selective 2 ALLOW selection pressure favours for ‘selected for’\nadvantage / are selected for ; 2 ALLOW selection pressure is against for ‘selected against’\n3 ALLOW pass on genes (to offspring / next generation) for\n3 in woodland, non-yellow / brown / pink / unstriped, snails, ‘reproduce’\nreproduce / pass on alleles\nOR\nin rough grass, yellow / striped, snails, reproduce / pass on\nalleles ; 4 ORA in rough grass, non-yellow / brown / pink / unstriped,\nsnails, decrease in frequency\n4 in woodland, non-yellow / brown / pink / unstriped, snails, OR\nincrease in frequency in woodland, yellow / striped, snails, decrease in frequency\nOR\nin rough grass, yellow / striped, snails, increase in frequency 5 ALLOW words e.g. allele for pink (shell) for ‘CP’\n;\n5 in woodland, CB / CP / N, are selected for / increase (in\nfrequency)\nOR\nin rough grass, CY / n, are selected for / increase (in\nfrequency) ;\n© Cambridge University Press & Assessment 2026 Page 15 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 13, 14, 15 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p13.png", "../answer-assets/9700_s26_ms_41-p14.png", "../answer-assets/9700_s26_ms_41-p15.png" ] }, { "id": "9700-2026-mj-41-q06", "question_id": "9700-2026-mj-41-q06", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "6(a)(i) domain: Eukarya ; 2 ALLOW Eukaryota / eukaryote(s) / phonetic spelling\ngenus: Ailurus and species: (Ailurus / A.) fulgens ; CON for small ‘a’ for Ailurus or big ‘F’ for fulgens\n\n6(a)(ii) 1 similar / shared, (described) morphological features / DNA 2 1 ALLOW share, physical / anatomical / biochemical,\nsequences, to, other Carnivora / others in that order ; features / traits / characteristics with Carnivora\n2 shared, common ancestor / phylogeny / evolutionary\nrelationships (with, other Carnivora / others in that order) ;\n\n6(b) any three from: 3 IGNORE advice for future actions\n(yes / successful, because):\n1 (red panda species) has not, died out / gone extinct OR 1 ALLOW insurance population maintained\ngenetic variation preserved ;\n(no / unsuccessful, because):\n2 habitat loss / wild population decline, has, continued / not 2 ALLOW habitats not, conserved / protected / restored\nstopped ;\n3 few reintroductions have occurred / reintroduction only 4 e.g. captive bred / zoo bred / released, animals may not\nstarted in 2011 ; survive in wild\n4 AVP ;\n© Cambridge University Press & Assessment 2026 Page 16 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n6(c) any five from: 5\n1 increase birth rate / overcome reluctance to mate ;\n2 IVF / in vitro fertilisation / fertilisation in test tube ; 2 ALLOW petri dish for ‘test tube’\n3 hormone / FSH / LH, so produce many (mature),\neggs / oocytes / follicles\nOR hormone / FSH/ LH, for superovulation / to increase\novulation ;\n4 harvest, oocytes / eggs (from, ovary / oviduct), and 4 ALLOW take gametes from both male and female\nsperm(atazoa) ;\n5 embryo transfer / introduce embryo, to uterus ;\n6 hormone / oestrogen / progesterone, prepares, uterus\nlining / endometrium ;\n7 correct ref. to surrogate, mother / female ; 7 CON in wrong context e.g. AI / SCNT\n8 of, same / related, species ; 8 ALLOW another red panda (female)\n9 AVP ; 9, 10 e.g. artificial insemination / AI / semen placed in uterus\n10 AVP ;\nembryo screening / select healthy embryos to implant\nzoos exchange, sperm / embryos, for genetic diversity OR\nfrozen, ova / semen, from dead pandas, for genetic diversity\nOR\nsperm bank for, genetic diversity / store alleles idea\n© Cambridge University Press & Assessment 2026 Page 17 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 16, 17 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p16.png", "../answer-assets/9700_s26_ms_41-p17.png" ] }, { "id": "9700-2026-mj-41-q07", "question_id": "9700-2026-mj-41-q07", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "7(a)(i) (92 – 35) ÷ 35  100 OR (57 ÷ 35)  100 ; 2\n163 (%) ; ECF answer to 3 s.f. from correct working with mis-read\ngraph figures (from bars or trend line)\ne.g. if (63 – 3) ÷ 3  100 ALLOW 2000 ECF\n\n7(a)(ii) LIST RULE APPLIES but IGNORE incompletely named 4 ALLOW 1 mark for ‘limiting factor for / limits rate of / affects\nfactors rate of, photosynthesis’ if 2R / 4R / 6R not given\nany two pairs of a factor (F) and reason (R) from:\n1F light intensity ; 2R ALLOW limiting factor for ‘limits rate of’\n2R limits / affects, rate of, light-dependent 2R ALLOW description e.g. if light intensity is higher\nstage / photophosphorylation / photoactivation ; photophosphorylation, increases / occurs more / is faster\n3F carbon dioxide concentration ; 4R ALLOW limiting factor for ‘limits rate of’\n4R limits / affects, rate of, light independent stage / Calvin 4R ALLOW description\ncycle / carboxylation / carbon fixation ;\n5F temperature ; 6R ALLOW limiting factor for ‘limits rate of’\n6R limits / affects, rate of, (named) enzyme-catalysed 6R ALLOW description\nreactions / formation of enzyme-substrate complexes / Calvin 6R IGNORE high temperature denatures enzymes\ncycle / light independent stage / photolysis ; 6R CON low temperature denatures enzymes\n7F (concentration in water of) nitrate / phosphate / (other\n7F AVP ; named) mineral ion / mineral nutrients / dissolved oxygen\nOR fertiliser run-off / sewage discharge (into water / ocean)\nOR (water / ocean) pH\n8R AVP ; 8R linked to, role in metabolism / named organic molecule\n© Cambridge University Press & Assessment 2026 Page 18 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n7(b) any four from: 4 IGNORE SR, troponin, tropomyosin, actin, myosin\nECF after first error of each type: ‘into membrane’, wrong ion\nsymbol, omitting to state ion\nECF for ‘less’ instead of ‘no’ after first error\n1 sodium ions / Na+, do not enter, motor neurone / axon ; 1 ALLOW Na+ moves in at ligand-gated channels only\n1 DO NOT ALLOW Na+ enter membrane for ‘enter neurone’\n1 DO NOT ALLOW toxin, mimics ACh / binds to ACh\nreceptors (i.e. affects ligand-gated channel)\n2 no, propagation / transmission / passing on, of, 2 ALLOW impulse, not sent to / doesn’t reach, synaptic knob\ndepolarisation / action potential / impulse ;\n3 no Ca2+ enter, synaptic knob / presynaptic neurone ; 3 ALLOW Ca2+ channels don’t open at, synaptic\nknob / presynaptic neurone\n4 no acetylcholine, release / exocytosis ; 4 ALLOW ACh\n4 ALLOW acetylcholine does not diffuse across,\ncleft / neuromuscular junction / synapse\n5 no, stimulation of / depolarisation of / binding of 5 ALLOW muscle cell membrane / postsynaptic membrane,\nacetylcholine to, sarcolemma ; for ‘sarcolemma’\n5 DO NOT ALLOW membrane of postsynaptic\nknob / postsynaptic neurone\n5 DO NOT ALLOW toxin, mimics acetylcholine / binds to\nacetylcholine receptors (i.e. affects ligand-gated channel)\nbut ECF from mp1\n6 no, T-tubule, depolarisation / action potential / impulse\ntransmission ;\n© Cambridge University Press & Assessment 2026 Page 19 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p18.png", "../answer-assets/9700_s26_ms_41-p19.png" ] }, { "id": "9700-2026-mj-41-q08", "question_id": "9700-2026-mj-41-q08", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "8(a)(i) any three from: 3 CON receptor cell confused with receptor protein once then\nECF\n1 detect stimuli ;\n2 receptor potential ; 2 ALLOW generator potential\n3 impulse / action potential, in sensory neurone ; 3 DO NOT ALLOW pass, receptor potential / stimulus, to\nsensory neurone\n4 ref. to chemoreceptors on (moth) antenna ;\n5 act as transducers ; 5 ALLOW description e.g. convert energy from one form to\nanother / convert (named) stimulus energy to electrical\nenergy\n\n8(a)(ii) any three from: 3 IGNORE gene expression\n1 switch gene, on / off ; 1 ALLOW gene switching\n2 transcription factor ; 2 ALLOW activator / repressor\n3 allows / stops, RNA polymerase to, act / bind ;\n4 gene for enzyme to make, lipid / scent (chemical) ;\n5 AVP ; 5 e.g. light detected / light receptor / phytochrome\ne.g. clock genes\ne.g. negative feedback\ne.g. mRNA / protein, degradation (→ daily cycle)\n\n8(b) A: mRNA ; 3 A: ALLOW messenger RNA\nB: cDNA / ssDNA ; B: ALLOW complementary / single-stranded, DNA\nC: (ss DNA) probe / reporter / oligo ; C: IGNORE complementary\n© Cambridge University Press & Assessment 2026 Page 20 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p20.png" ] }, { "id": "9700-2026-mj-41-q09", "question_id": "9700-2026-mj-41-q09", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 9, "status": "available", "reason": null, "text": "9(a) any two from: LIST RULE APPLIES 2 IGNORE phosphorylation\n1 make, nucleic acid / polynucleotide / DNA / RNA ; 1 ALLOW DNA replication / transcription\n2 make (named), peptide / polypeptide / protein ; 2 ALLOW protein synthesis / translation\n3 make, lipid / triglyceride / phospholipid (from smaller units); 3 ALLOW lipogenesis\n4 make (named), disaccharide / polysaccharide (from 4 ALLOW glycogenesis\nsmaller units) ;\n5 Calvin cycle ; 5 ALLOW regenerate RuBP\n6 AVP ; 6 e.g. join amino acid to tRNA\n\n9(b)(i) 1 growth / larger / more cells (to support) ; 2\n2 mobile / moves / locomotion / swims / muscle contraction ;\n3 AVP ; 3 e.g. nerve impulses / nervous system activity ref.\nreproduction\n\n9(b)(ii) substrate-level / substrate-linked, phosphorylation ; 2\noxidative phosphorylation / chemiosmosis ;\n\n9(c)(i) 1430 / 2020 (= 0.7079) ; 2\nanswer: 0.71 ; ECF for answer rounded to 2 s.f. from incorrect working\n\n9(c)(ii) A ; 1\n© Cambridge University Press & Assessment 2026 Page 21 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 21 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p21.png" ] }, { "id": "9700-2026-mj-41-q10", "question_id": "9700-2026-mj-41-q10", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 9, "status": "available", "reason": null, "text": "10(a) any three from: 3 IGNORE genetic screening\n1 change / manipulate / alter / modify, (organism’s) 1 IGNORE genetic information\nDNA / genetic material / genome ; 1 ALLOW recombinant DNA in organism context\n1 ALLOW adjust for ‘change’\n2 to, change / modify, (organism’s) 2 ALLOW traits / features, for ‘characteristics’\ncharacteristics / phenotype ;\n3 new / different / functional, protein produced ; 4 ALLOW gene editing / edit genes\n4 transfer / add / insert, gene / allele / DNA (into a recipient 4 ALLOW delete / replace, gene (in GMO)\norganism) ;\n© Cambridge University Press & Assessment 2026 Page 22 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n10(b) any six from: 6\nprepare the vector\n1 (normal / dominant) allele / gene, for ADA / adenosine 1 ALLOW IL2RG / DCLRE1C, for ‘gene for ADA’\ndeaminase ;\n2 inserted into, vector / virus ; 2 ALLOW retrovirus / lentivirus\n2 IGNORE adenovirus / AAV / plasmid\n3 virus modified so it cannot replicate ; 3 ECF if incorrect virus named e.g. adenovirus / AAV\nobtain and modify patient cells\n4 get (haemopoietic / lymphoid) stem cells from (patient) 4 ALLOW get T, lymphocytes / cells, from blood\nbone marrow ; 5 ALLOW idea of inserting, virus / vector, into\n5 mix / culture, (engineered) vector, with, patient’s / stem, patient’s / stem, cells (in vitro / ex vivo)\ncells (in vitro / ex vivo) ; 5 ALLOW if patient cells stated to be T cells\n6 drug to increase stem cells (in bone marrow) before mp 4\nOR\ndrug / chemotherapy / radiotherapy, to kill stem cells (to\nmake space)\nbefore mp 7 ;\nreturn modified cells to patient\n7 reintroduce (GM / transgenic) cells to, patient / bone 7 ALLOW patient T cells returned to blood\nmarrow / blood ;\n8, 9 gene, cloned in / taken from, GM bacteria\n8 AVP ; multiply transformed, patient / T / stem, cells\n9 AVP ; T-lymphocytes / T-cells, produce ADA (protein / enzyme)\n© Cambridge University Press & Assessment 2026 Page 23 of 23\nTrace ID: PC-791D658355\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/41 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_41.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-41.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_41-p22.png", "../answer-assets/9700_s26_ms_41-p23.png" ] }, { "id": "9700-2026-mj-42-q01", "question_id": "9700-2026-mj-42-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "1(a) F ; 4\nA ;\nB ;\nB and C ;\n\n1(b) any four from: 4\n1 (voltage-gated) Na+ channels open and Na+ move in (to axon / neurone) ;\n2 (so) depolarisation (of membrane) ;\n3 ref. to reaching threshold (potential / value / level / voltage) ; R frequency\n4 (voltage-gated) K+ channels open and K+ move out (of axon / neurone) ;\n5 (so) repolarisation (of membrane) ;\n6 ref. to hyperpolarisation (of membrane) ;\nQuestion Answer Marks", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p08.png" ] }, { "id": "9700-2026-mj-42-q02", "question_id": "9700-2026-mj-42-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "2(a) 2\nA B\nA pointing to embryo ;\nB pointing to aleurone layer ;\n© Cambridge University Press & Assessment 2026 Page 8 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(b)(i) C – (gibberellin / GA) receptor ; A GID1 3\nD – DELLA (protein / repressor) ;\nE – transcription factor / phytochrome interacting factor / PIF ;\n\n2(b)(ii) promoter ; 2\namylase ; A mRNA for amylase\n\n2(c) decreases / short(er) / dwarf ; 1\nQuestion Answer Marks", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p08.png", "../answer-assets/9700_s26_ms_42-p09.png" ] }, { "id": "9700-2026-mj-42-q03", "question_id": "9700-2026-mj-42-q03", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 13, "status": "available", "reason": null, "text": "3(a)(i) any three from: 3\n1 PCR to amplify DNA ;\n2 (gel) electrophoresis, to compare / separate, DNA fragments ;\n3 microarray to, compare / analyse, genomes ; A polymorphisms\n4 database / bioinformatics, to, compare / analyse, sequences of, (DNA) bases / nucleotides ;\n© Cambridge University Press & Assessment 2026 Page 9 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n3(a)(ii) any four from: 4\n1 allopatric (speciation) ;\n2 idea of no contact so, reproductive isolation / no gene flow (between populations) ;\n3 different mutations occur (in each population) ;\n4 different selection pressures (for each population) ;\n5 ref. to (named) morphological / (named) behavioural / ecological / niche, differences (between populations) ;\n6 so can no longer interbreed to produce fertile offspring ;\n\n3(a)(iii) 1 they are now different species / speciation has taken place ; 3\n2 (different mating calls shows) behavioural, isolation / separation ;\n3 (when S female and N male mate) offspring not produced / (fertilised) eggs are not viable ;\n\n3(b) 1 genes / genetic and environment(al) ; 3\n2 polygenes / many genes involved ;\n3 diet / food (availability) / competition for food / nutrients / temperature / disease ;\n© Cambridge University Press & Assessment 2026 Page 10 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 9, 10 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p09.png", "../answer-assets/9700_s26_ms_42-p10.png" ] }, { "id": "9700-2026-mj-42-q04", "question_id": "9700-2026-mj-42-q04", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "4(a) 3\n1. (deliberate) manipulation / changing, of, DNA / genetic material / genome ;\n2. to, modify / improve / add, (named) characteristics of, organism / crop / plant ;\n3. ref. to add / delete / replace, gene / allele (into crop)\nor\ngene editing ; A CRISPR\n\n4(b) any answer between 295 and 305 ;\n© Cambridge University Press & Assessment 2026 Page 11 of 23\n( 1 7 0\n4\n−\n2\n4\n. 5\n2 . 5 )\n2\n 100\nIf incorrect answer max 1 mark for this equation\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n4(c) any five from: 5\n1 idea of increase / high, productivity / yield / food quantity ; A named example\n2 improve (named) quality ;\n3 ref. to herbicide / weedkiller, tolerance / resistance ;\n4 reduces / no, competition from weeds\nor\nso crops get more, light / water / AW ;\n5 ref. to insect / pest, resistance ;\n6 less / no, crop damage\nor\nless food wastage ;\n7 ref. to economic advantage ;\n8 tolerance to name factor ; e.g. disease / environmental extreme / frost / high temperatures / windy / less fertile soil\n© Cambridge University Press & Assessment 2026 Page 12 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p11.png", "../answer-assets/9700_s26_ms_42-p12.png" ] }, { "id": "9700-2026-mj-42-q05", "question_id": "9700-2026-mj-42-q05", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "5(a) 4\nparental phenotypes: ash-red male blue female\nparental genotypes: ZAZBr ZBlW ;\noffspring\nparental\ngametes ZBl W\nZA genotype ZA ZBl genotype ZA W\nphenotype ash-red phenotype ash-red\nmale female\nZBr genotype ZBl ZBr genotype ZBr W\nphenotype blue phenotype brown\nmale female\nallow one mark for correct parental gametes (in either orientation on the table) ;\nallow one mark for correct offspring genotypes ;\nallow one mark for correct matching colour and sex phenotypes ;\nif male parent is incorrect then ecf max 1 for correct offspring genotypes from gametes\n\n5(b) sex-linkage ; 2\nmultiple alleles / dominance hierarchy ;\n© Cambridge University Press & Assessment 2026 Page 13 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n5(c) 1 cross (ash-red male) with brown female ; Ignore genotype ZBr W 3\nplus any two from:\n2 if all offspring are ash-red then (male parent is), ZA ZA / AW ; A homozygous for ZA\n3 if (any) offspring are blue then (male parent is), ZA ZBl / AW ;\n4 if (any) offspring are brown then (male parent is), ZA ZBr / AW ;\n© Cambridge University Press & Assessment 2026 Page 14 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 13, 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p13.png", "../answer-assets/9700_s26_ms_42-p14.png" ] }, { "id": "9700-2026-mj-42-q06", "question_id": "9700-2026-mj-42-q06", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "6(a) facilitated diffusion ; 1\n\n6(b) 480 ; 2\nmax 1 if not as a whole number 479.5918367\nIf standard form incorrect allow max 1 if evidence of 4.7 divided 9.8\n\n6(c) any four from: 4\n1 ref. to, many, impulses / action potentials (occurring)\nor\nmany synapses / many connections between neurones ;\n2. ref. to sodium potassium pump / active transport of Na+ and K+ ; R channel\n3 setting up / maintaining, ion gradient(s) ;\n4 setting up / maintaining, resting potential(s) ;\n5 production / recycling, of, neurotransmitters / acetylcholine / ACh ;\n6 production / recycling / movement, of vesicles\nor\nexocytosis (of neurotransmitter) / endocytosis ; R exocytosis of vesicles\n7 production of acetylcholinesterase ;\n© Cambridge University Press & Assessment 2026 Page 15 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n6(d) any three from: 3\n1 (caffeine) binds to (adenosine) receptors ; R active site\nor\ninhibits / blocks, binding of adenosine to receptors / AW ;\n2 less ATP made during sleep / more ATP made whilst awake ;\n3 postsynaptic (neurone) activity is not inhibited / can occur / AW ;\n4 (less adenosine bound to receptors) cannot promote sleep / promotes wakefulness / AW ;\n© Cambridge University Press & Assessment 2026 Page 16 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p15.png", "../answer-assets/9700_s26_ms_42-p16.png" ] }, { "id": "9700-2026-mj-42-q07", "question_id": "9700-2026-mj-42-q07", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "7(a) class 2\nand\nfamily ;\nCoenagrion\nand\n(Coenagrion) mercuriale ;\n\n7(b) any four from: 4\nAnimalia Plantae\n1 no, chloroplasts / chlorophyll vs chloroplasts / chlorophyll ;\n2 heterotrophic / cannot vs autotrophic / phototroph / can ;\nphotosynthesise / described photosynthesise / described\n3 no cell walls vs cell walls ;\n4 vacuoles, small / temporary vs vacuoles, large / permanent ;\n5 glycogen (store) vs starch (store) ;\n6 locomotion / motility / mobility vs no, ;\nlocomotion / motility / mobility\n7 nervous system vs no nervous system ;\n© Cambridge University Press & Assessment 2026 Page 17 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n7(c)(i) any four from: 4\n1 habitat, destruction / loss Ignore deforestation\nor\ndecrease in, open vegetation / slow-flowing water\nor\nref. to (now) fast-flowing water ;\n2 (named) water pollution ;\n3 reduction in, (named) food (supply) / prey (numbers)\nor\nincreased competition for food ;\n4 increased predation ; A new predator\n5 (named) climate change ; e.g. flooding / drought / change in water temperature / global warming\n6 new disease ;\n\n7(c)(ii) any two from: 2\n1 (flying insects / adults) difficult to, (re)capture / mark ;\n2 idea of adults not alive long enough to be caught twice / adults may die before being caught for the second time / new\nadults emerge before recapture ;\n3 ref. to migration ;\n4 small population ;\n© Cambridge University Press & Assessment 2026 Page 18 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p17.png", "../answer-assets/9700_s26_ms_42-p18.png" ] }, { "id": "9700-2026-mj-42-q08", "question_id": "9700-2026-mj-42-q08", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "8(a) 4\nlocation of Na+ / K+ pumps P ; Ignore Q\nlocation of cotransport proteins S ; Ignore P\nstructures through which glucose P + S ; Ignore Q\nmolecules pass\nprevents leakage of fluid R ;\n\n8(b) any seven from: 7\n1 increase in ADH released ; Ignore produced A secreted\n2 (ADH released from) posterior pituitary ;\n3 ADH binds to receptors ;\n4 in, cell surface / basal, membrane, of collecting duct (cells) ;\n5 cAMP / secondary messenger, produced ;\n6 ref. to enzyme cascade / signal amplification / described ;\n7 vesicles (with aquaporins) move to / fuse with, cell surface / luminal, membrane ;\n8 more aquaporins in the, cell surface / luminal, membrane ;\n9 increase in (cell / membrane / collecting duct) permeability to water ;\n10 (more) water moves out of, lumen / collecting duct / filtrate, into, cell / tissue fluid / blood ;\n11 by, osmosis / down the water potential gradient ;\n12 (more) concentrated / small(er) volume, urine produced ;\n© Cambridge University Press & Assessment 2026 Page 19 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p19.png" ] }, { "id": "9700-2026-mj-42-q09", "question_id": "9700-2026-mj-42-q09", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 11, "status": "available", "reason": null, "text": "9(a) any three from: 4\nless hexokinase so:\n1 less glucose, phosphorylated / activated ;\n2 less glucose diffuses into cell (as less steep concentration gradient) ;\n3 less, glycolysis / formation of pyruvate ;\n4 less ATP formed ;\n5 loss of red blood cells / anaemia / less oxygen transport ;\nplus\nsymptom\n6 fatigue / shortness of breath / faint / feeling dizzy ;\n\n9(b) any four from: 4\n1 acetyl CoA / acetyl group / acetate / 2C fragment, combines with oxaloacetate to form citrate ;\n2 decarboxylation / carbon dioxide produced ;\n3 dehydrogenation / oxidation (of named intermediate) ;\n4 reduced, NAD / FAD, produced ;\n5 ATP produced by substrate-linked phosphorylation ;\n6 oxaloacetate, recycled / regenerated / formed again ;\n© Cambridge University Press & Assessment 2026 Page 20 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n9(c) any three from: 3\n1. pyruvate / (net 2) ATP, formed by glycolysis\nor\nsubstrate-linked phosphorylation occurs in glycolysis ;\n2 pyruvate reduced by reduced NAD ; Reject pyruvate is dehydrogenated\n3 lactate formed / lactate fermentation ; A lactic acid\n4 NAD, regenerated / recycled\nor\nreduced NAD oxidised (to NAD) / reduced NAD converted to NAD ;\n5 AVP ; e.g. lactate dehydrogenase\n© Cambridge University Press & Assessment 2026 Page 21 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 20, 21 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p20.png", "../answer-assets/9700_s26_ms_42-p21.png" ] }, { "id": "9700-2026-mj-42-q10", "question_id": "9700-2026-mj-42-q10", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 10, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 8, "status": "available", "reason": null, "text": "10(a) any four from: 4\nstructure function in photosynthesis\n1 stroma site of, (enzymes in) light-independent stage / Calvin cycle ;\nsite of, light-dependent stage / photosystems /\n2 ;\n(named) pigments / oxygen-evolving complex\nthylakoid\nmembranes\ncontains, electron transport chain / ETC / ATP\n3 ;\nsynthase / electron carriers\nto contain many, (named) pigment / photosystems\ngrana /\n4 or ;\ngranum\nincrease surface area for light (energy) absorption\nthylakoid,\nref. to setting up proton gradient / contains a high\n5 space / ;\nconcentration of protons\nlumen\n6 DNA codes for (named) proteins / ribosomes ;\n7 ribosomes translation (of mRNA) into / production of, (named) proteins ;\n\n10(b)(i) B = 0.42 ; 1\n\n10(b)(ii) A = carotene 1\nB = chlorophyll b ;\n© Cambridge University Press & Assessment 2026 Page 22 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n10(b)(iii) any two from: 2\n1 act as accessory pigments ; Ignore secondary pigments\n2 absorbs light wavelengths not absorbed by, reaction centre / primary pigment / chlorophyll a ;\n3 so extends the range of wavelengths absorbed ;\n4 pass energy to, reaction centre / primary pigment / chlorophyll a ;\n© Cambridge University Press & Assessment 2026 Page 23 of 23\nTrace ID: PC-913B5F5E92\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/42 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 22, 23 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_42.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-42.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_42-p22.png", "../answer-assets/9700_s26_ms_42-p23.png" ] }, { "id": "9700-2026-mj-43-q01", "question_id": "9700-2026-mj-43-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "1(a) F ; 4\nE ;\nC ;\nD ;\n\n1(b) any five from: 5\n1 ref.to muscles need a large ATP supply / muscles have high respiration rate ;\n2 glucose used up / glucose (concentration) becomes low(er) ;\n3 glucagon released (by alpha cells in pancreas) ;\n4 glycogenolysis / gluconeogenesis (in liver cells) ; A description\n5 glucose released into blood / blood glucose (concentration) increases ;\n6 ref. to water loss through sweating ;\n7 idea of ADH reducing water loss ; A vasopressin\n8 AVP ; e.g. adrenaline (on muscle cells / liver cells) causes, glycogenolysis / gluconeogenesis e.g. cortisol causes\ngluconeogenesis in liver cells / supresses insulin release\n© Cambridge University Press & Assessment 2026 Page 8 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p08.png" ] }, { "id": "9700-2026-mj-43-q02", "question_id": "9700-2026-mj-43-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 9, "status": "available", "reason": null, "text": "2(a) A – prophase II ; 3\nB – telophase I ; A (early) prophase II\nC – metaphase II ;\n\n2(b) any three from: 3\n1 (chromosomes with) same, genes / gene loci ;\n2 (but potentially) different alleles ;\n3 one inherited from each parent / one maternal and one paternal chromosome ;\n4 same, size / length ;\n5 same, shape / position of centromere ;\n6 AVP ; e.g. same banding pattern\n\n2(c) any three from: 3\n1 (meiosis) produces gametes ;\n2 (gametes) are haploid / have one set of chromosomes ;\n3 fertilisation / fusion of gametes, form a zygote ;\n4 zygote, is diploid / has two sets of chromosomes ;\n5 maintains chromosome number / prevents a change in chromosome number ;\n© Cambridge University Press & Assessment 2026 Page 9 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 9 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p09.png" ] }, { "id": "9700-2026-mj-43-q03", "question_id": "9700-2026-mj-43-q03", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "3(a) 1 idea of use primers, specific / complementary / AW, to mutant (HBB) allele ; 4\n2 denature DNA / separate DNA into (two) strands ;\n3 annealing / binding, of primers ;\n4 DNA, elongation / extension / synthesis / replication ;\n\n3(b) homozygous normal = 3 2\nhomozygous mutant = 1\nheterozygous = 2 and 4\none correct = one mark\nall three correct = two marks ; ;\n\n3(c) any four from: 4\n1 take DNA sample from cell (of person) ;\n2 make DNA single-stranded ;\n3 add fluorescent, label / tag / dye / chemical, to the DNA (sample) ; R marker gene\n4 microarray / chip, has (ss)DNA, probe(s) for mutant (HBB) allele ;\n5 (ss)DNA, hybridises with / binds to / complementary base pairs with, probe(s) (on microarray) ;\n6 fluorescence shows presence (of mutant allele) ;\n7 AVP ; e.g. ref. to wash off excess (ss)DNA after hybridisation\nUV light / laser (scan), to see fluorescence\n© Cambridge University Press & Assessment 2026 Page 10 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p10.png" ] }, { "id": "9700-2026-mj-43-q04", "question_id": "9700-2026-mj-43-q04", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "4(a) 1 q = √0.11 or q = 0.33166 3\nand\np = 1 – 0.33166 or p = 0.66834 ;\n2 2pq = 2  0.66834  0.33166 or 2pq = 0.44332 and  100 ;\n3 44 ;\nmax 1 if no working is shown but have correct answer\n\n4(b) apply ora throughout 3\n1 (only) continuous, is polygenetic / involves more than two genes / involves many genes ;\n2 in continuous different alleles have a small(er) effect (on the trait) ;\n3 (only) continuous has, genes / alleles, showing an additive effect ;\n\n4(c) any three from: 3\n1 founder effect / genetic drift ; A description\n2 geographical, isolation / separation / barrier (between populations) ;\n3 no gene flow / no interbreeding / reproductive isolation (between populations) ;\n4 different mutations occurred ;\n5 different, selection pressures / environments ;\n6 different changes in allele frequencies ;\n© Cambridge University Press & Assessment 2026 Page 11 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 11 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p11.png" ] }, { "id": "9700-2026-mj-43-q05", "question_id": "9700-2026-mj-43-q05", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "5(a) recessive 2\nphenotype of (recessive) allele is masked by a dominant allele\nor\ntwo copies of the (recessive) allele are needed for phenotype (to be displayed)\nor\nalleles only affect the phenotype in the absence of a dominant allele\nor\n(genotype) must be homozygous for the (recessive) allele to affect the phenotype ;\ncodominant\nboth alleles affect the phenotype (in the heterozygote) ;\n\n5(b) 3\nblood group genotypes\nA IA IA IA IO ;\nB IB IB IB IO ;\nAB IA IB\nO IO IO ;\n© Cambridge University Press & Assessment 2026 Page 12 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n5(c) parental phenotypes: ( B Rh+ O Rh+ ) 5\nparental genotypes: IB IO Dd IO IO Dd\nparental IBD IBd IOD IOd\ngametes\nIOD IBIODD IBIODd IOIODD IOIODd\nB Rh+ B Rh+ O Rh+ O Rh+\nIOd IBIODd IBIOdd IOIODd IOIOdd\nB Rh+ B Rh- O Rh+ O Rh-\nratio of offspring phenotypes:\nB Rh+ O Rh+ B Rh- O Rh-\n3 : 3 : 1 : 1\nallow one mark for correct parental genotypes ;\nallow one mark for correct parental gametes ;\nallow one mark for correct offspring genotypes ;\nallow one mark for correct, matching, phenotypes ;\nallow one mark for correct ratio ;\napply ecf – if incorrect parental phenotype for gene I, ecf for Rhesus gene, evidence of correct parental gametes, offspring\ngenotypes and matching phenotypes to max 3 marks\n© Cambridge University Press & Assessment 2026 Page 13 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 12, 13 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p12.png", "../answer-assets/9700_s26_ms_43-p13.png" ] }, { "id": "9700-2026-mj-43-q06", "question_id": "9700-2026-mj-43-q06", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 9, "status": "available", "reason": null, "text": "6(a) any six from: 6\n1 afferent arteriole is wider than efferent (arteriole) ;\n2 (creates) high(er), hydrostatic / blood, pressure ;\n3 in, glomerulus / capillaries ;\n4 fluid / water / plasma, forced through gaps between endothelial cells ;\n5 basement membrane acts as a (molecular) filter ;\n6 only, named molecules / ions / molecules less than 68 000–70 000 (R)MM, can pass through (basement membrane)\nor\nred blood cells / large proteins, cannot pass through (the endothelium) ;\n7 podocyte has, gaps / slits / projections / pores ;\n8 fluid / water / filtrate, passes into the, Bowman’s capsule ;\n\n6(b) any three from: 3\n1 reduces secretion of ADH ; Ignore production\n2 idea that less / no, ADH binds to receptors (at the collecting duct) ;\n3 ref. to fewer / no, aquaporins, in / added to, membranes (of cells in collecting duct) ;\n4 ref. to less water reabsorbed (at collecting ducts) ;\n5 increase in blood pressure so increase, in GFR / volume of glomerular filtrate ;\n© Cambridge University Press & Assessment 2026 Page 14 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p14.png" ] }, { "id": "9700-2026-mj-43-q07", "question_id": "9700-2026-mj-43-q07", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 12, "status": "available", "reason": null, "text": "7(a) any three from: 3\n1 habitat, destruction / loss ; A deforestation\n2 reduction in, food (supply) / prey (numbers)\nor\nincreased competition for food ;\n3 hunted (by humans) for, food / bushmeat\nor\nincreased predation ; A new predator\n4 (named) climate change ; e.g. drought / global warming\n5 new disease ;\n6 illegal pet trade ;\n\n7(b) any four from: 4\n1 IVF / in vitro fertilisation ;\n2 hormone(s) / FSH / LH, to stimulate (super)ovulation ;\n3 idea of in vitro, fertilisation of eggs / production of embryos ;\n4 embryo transfer / introduce embryo, to uterus ;\n5 ref. to surrogacy ;\n6 and 7 AVP ; ; e.g. artificial insemination / AI\nsame / related species\nref. to embryo screening\nref. to outbreeding for genetic diversity\nref. to frozen ova / semen / embryos / frozen zoo, for,\nfuture use / as a gene bank\n© Cambridge University Press & Assessment 2026 Page 15 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n7(c)(i) correct working ; [33  46] ÷ 9 (=168.7) 2\n169 ;\n\n7(c)(ii) any three from: 3\n1 (large / flightless so) easy to, mark / catch ;\n2 (cockroaches) are mobile ;\n3 no migration ;\n4 constant / large, population size ;\n© Cambridge University Press & Assessment 2026 Page 16 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 15, 16 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p15.png", "../answer-assets/9700_s26_ms_43-p16.png" ] }, { "id": "9700-2026-mj-43-q08", "question_id": "9700-2026-mj-43-q08", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 10, "status": "available", "reason": null, "text": "8(a) 4\nfunction part of seed\ngibberellin synthesis embryo ;\nstarch store endosperm ;\namylase synthesis aleurone layer ;\nmaltose production endosperm ;\n\n8(b)(i) any three from: 3\n1 protons / H+ ions, pumped / actively transported (into cell wall) ;\n2 (so) pH (in cell wall) decreases / (cell wall) becomes more acidic ;\n3 expansins, activated / AW ;\n4 microfibrils (in cellulose) loosen (to allow elongation) ; Ignore weaken\n\n8(b)(ii) any three from: 3\n1 K+ / potassium ions, enter, cell / cytoplasm ; R active transport\n2 water potential of, cell / cytoplasm, decreases\nor\nwater potential of the cell wall increases ;\n3 water enters (cell through aquaporins) by, osmosis / down the water potential gradient ;\n4 cell volume increases / cell expands / increase in turgor pressure (inside cell) ;\n© Cambridge University Press & Assessment 2026 Page 17 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 17 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p17.png" ] }, { "id": "9700-2026-mj-43-q09", "question_id": "9700-2026-mj-43-q09", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 10, "status": "available", "reason": null, "text": "9(a) any four from: 4\nstructure function in respiration\nouter permeable for (diffusion of), oxygen / carbon ;\n1\nmembrane dioxide / pyruvate / reduced NAD\n2 site of, chemiosmosis / oxidative phosphorylation ;\n(forms) cristae / is folded, to provide, large / increased, ;\ninner\nsurface area\nmembrane\n3 or\n(has) many, electron transport chains / ETCs / electron\ncarriers / ATP synthase (molecules)\nintermembrane ref. to setting up proton gradient / high concentration of ;\n4\nspace protons\n5 matrix site of (enzymes in) the, Krebs cycle / link reaction ;\n6 DNA codes for, (named) proteins / ribosomes / RNA ;\n\n9(b) any three from: 3\n1 idea that more active the cell means more mitochondria ;\n2 idea that heart muscle (cell) contraction needs lots of ATP ;\n3 liver cell carries out, glycogenolysis / glycogenesis / gluconeogenesis / deamination / detoxification, so needs ATP ;\n4 idea that red blood cells need room for haemoglobin ;\n© Cambridge University Press & Assessment 2026 Page 18 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n9(c) any three from: 3\n1 glucose phosphorylated by ATP to form fructose (1,6-)bisphosphate ;\n2 fructose (1,6-)bisphosphate splits into two molecules of, triose phosphate / TP ; R hydrolysed\n3 triose phosphate / TP, oxidised to pyruvate ; A dehydrogenated\n4 ATP / reduced NAD, produced ;\nQuestion Answer Marks", "source_pages": [ 18, 19 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p18.png", "../answer-assets/9700_s26_ms_43-p19.png" ] }, { "id": "9700-2026-mj-43-q10", "question_id": "9700-2026-mj-43-q10", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 12, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 electrons emitted (from chlorophyll) ; A electrons excited\n2 electrons pass along, electron transport chain / ETC, releasing energy ;\n3 (energy is used to) pump protons into thylakoid space ;\n4 ref. to proton gradient ;\n5 protons pass through ATP synthase into stroma ;\n6 ATP produced from ADP and Pi ;\n\n10(b)(i) ribulose bisphosphate ; 2\ntriose phosphate ;\n\n10(b)(ii) causes reduction ; A reduced NADP is oxidised 2\n(so) converts GP to TP ;\n\n10(b)(iii) amino acid ; Ignore proteins 1\n© Cambridge University Press & Assessment 2026 Page 19 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n10(c) 1 carbon dioxide concentration is the limiting factor when, rate is increasing / AW ; 3\n2 as graph levels off another factor becomes limiting ;\n3 temperature / light intensity (become limiting) ;\n4 AVP ; e.g. water shortage (closes stomata) causing low(er) concentration of carbon dioxide ;\n© Cambridge University Press & Assessment 2026 Page 20 of 20\nTrace ID: PC-C51CA5D8F2\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/43 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 19, 20 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_43.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-43.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_43-p19.png", "../answer-assets/9700_s26_ms_43-p20.png" ] }, { "id": "9700-2026-mj-44-q01", "question_id": "9700-2026-mj-44-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 1, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 8, "status": "available", "reason": null, "text": "1(a) X attached to operator ; 1\n\n1(b) 2\nstructural gene product role of gene product\ngene\nlacZ β-galactosidase hydrolyses lactose to form glucose and galactose\nlacY lactose permease idea that lactose can enter,\nor cell / bacterium\nβ-galactoside permease\nlacA transacetylase transfers an acetyl group from one molecule to\nanother\nOne mark for each correct column\n\n1(c) (enzyme that is only) produced when, the substrate / lactose / inducer, is present ; A in larger amounts 1\n© Cambridge University Press & Assessment 2026 Page 8 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(d) any four from: 4\nB - population remains constant\n1 ref. to glucose has been used up ;\n2 (so bacterial) replication / division / binary fission, stops / slows ;\nB/C\n3 lac operon / (named) structural gene(s), switched on / transcribed / expressed\nor\n(named) enzyme(s) synthesised ;\nC – population size increases\n4 (so more) lactose enters ;\n5 lactose, hydrolysed / broken down, into, glucose / galactose (to make ATP) ;\n6 (for bacterial) replication / division / binary fission ;\n© Cambridge University Press & Assessment 2026 Page 9 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8, 9 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p08.png", "../answer-assets/9700_s26_ms_44-p09.png" ] }, { "id": "9700-2026-mj-44-q02", "question_id": "9700-2026-mj-44-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 2, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 8, "status": "available", "reason": null, "text": "2(a) 4\nion direction of movement of ion and type of cell action that results from movement of ion\nK+ into guard cells ; opening of stoma(ta)\ndepolarisation (of presynaptic membrane)\nNa+ into synaptic knob of presynaptic neurone or\naction potential generated ;\nvesicles, move towards / fuse with,\n(presynaptic) membrane\nCa2+ into synaptic knob of presynaptic neurone\nor\nexocytosis of acetylcholine / described ;\nfrom sarcoplasmic reticulum to sarcoplasm of cell\nCa2+ / calcium ion ; binding to troponin\nof striated muscle\n\n2(b) any four from: 4\n1 Na+ concentration in cells, decreases / is low\nor\nNa+ concentration gradient formed ;\n2 Na+ enter cells from, filtrate / lumen ;\n3 ref. to cotransport of glucose (from, filtrate / lumen) into cells ;\n4 glucose concentration in cells increases ;\n5 glucose moves (out of cells) into the blood ;\n© Cambridge University Press & Assessment 2026 Page 10 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 10 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p10.png" ] }, { "id": "9700-2026-mj-44-q03", "question_id": "9700-2026-mj-44-q03", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 3, "topic": "Classification, biodiversity and conservation", "topic_slug": "9700-topic-18-classification-biodiversity-and-conservation", "marks": 13, "status": "available", "reason": null, "text": "3(a) any four from: 4\n1 habitat, destruction / loss ; A deforestation\n2 (illegal) trade / human hunting / poaching ;\n3 decreased, food (supply) / prey (numbers)\nor\nincreased competition for food ;\n4 increased predation ; A new predator\n5 (named) climate change e.g. drought / global warming\nor\npollution ;\n6 new disease ;\n\n3(b) 146 / 145 ;; 2\nmax 1 mark if answer not to whole number\n\n3(c) any three from: 3\n1 (respiration) involves (named) enzyme ;\n2 low kinetic energy ;\n3 fewer collisions between enzyme and substrate / fewer enzyme-substrate complexes formed ;\n4 lower rate of diffusion (of named metabolite) ; e.g. oxygen / glucose\n5 AVP ; e.g. less NAD available\n© Cambridge University Press & Assessment 2026 Page 11 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n3(d) any four from: 4\n1 multicellular ;\n2 heterotrophic ;\n3 eukaryotic / nucleus ;\n4 reproduction (mostly) sexual ;\n5 ref. to glycogen (store) ;\n6 motile / mobile ;\n7 nervous system ;\n© Cambridge University Press & Assessment 2026 Page 12 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 11, 12 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-18-classification-biodiversity-and-conservation/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p11.png", "../answer-assets/9700_s26_ms_44-p12.png" ] }, { "id": "9700-2026-mj-44-q04", "question_id": "9700-2026-mj-44-q04", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 4, "topic": "Selection and evolution", "topic_slug": "9700-topic-17-selection-and-evolution", "marks": 9, "status": "available", "reason": null, "text": "4(a) any six from: 6\n1 allopatric (speciation) ;\n2 geographical, isolation / separation / barrier (between populations)\nor\nref. to Panama / land / barrier, separating populations ;\n3 (so) reproductive isolation / no gene flow / no interbreeding (between populations) ;\n4 different mutations ;\n5 different, selection pressures / environments ;\n6 different, alleles selected for / changes in allele frequency / gene pools ;\n7 ref. to (named) behavioural / ecological / niche, differences (between populations) ;\n8 no longer interbreed to produce fertile offspring ;\n\n4(b) ecosystem 3\n1 interactions of, community / all species / all populations ;\n2 ref. to abiotic / physical / non-living, and, biotic / biological / living, factors / environment ;\nniche\n3 role / function, of a species (in its ecosystem) ;\n© Cambridge University Press & Assessment 2026 Page 13 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 13 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-17-selection-and-evolution/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p13.png" ] }, { "id": "9700-2026-mj-44-q05", "question_id": "9700-2026-mj-44-q05", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 5, "topic": "Homeostasis", "topic_slug": "9700-topic-14-homeostasis", "marks": 11, "status": "available", "reason": null, "text": "5(a)(i) 833.3 ;;\n© Cambridge University Press & Assessment 2026 Page 14 of 22\n2 8 0\n3\n−\n0\n3 0\n2\n 100\nif answer incorrect award one mark for working\n\n5(a)(ii) any four from: 4\n1 insulin secreted by, pancreas / beta cells / Islets of Langerhans ;\n2 binds to receptors on (cell surface membrane of), liver / muscle, cells ;\n3 glucose transporter (proteins) added to muscle cell (surface membrane)\nor\nincreases permeability of muscle cell (to glucose) ;\n4 more glucose enters (cells) ;\n5 increase in respiration of glucose ;\n6 glycogenesis ; A described\n\n5(b)(i) glucose oxidase ; 2\nperoxidase ;\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n5(b)(ii) any three from: 3\nidentical to human insulin\n1 no, allergy / immune response / antibody response / side effects / rejection ;\n2 acts rapidly ;\n3 do not, develop tolerance to it / need larger doses ;\n4 no risk of, disease / infection ;\n5 no / fewer, (named) ethical issues ;\n© Cambridge University Press & Assessment 2026 Page 15 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 14, 15 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-14-homeostasis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p14.png", "../answer-assets/9700_s26_ms_44-p15.png" ] }, { "id": "9700-2026-mj-44-q06", "question_id": "9700-2026-mj-44-q06", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 6, "topic": "Photosynthesis", "topic_slug": "9700-topic-13-photosynthesis", "marks": 10, "status": "available", "reason": null, "text": "6(a) S ; 2\nP ;\n\n6(b)(i) 0.0044 ; 2\n23 ;\n\n6(b)(ii) 1 as light intensity increases rate of photosynthesis increases / AW ; 4\n2 data quote – 2 light intensities and 2 rates of photosynthesis plus units ;\nrelative light intensity rate of photosynthesis / min-1\n0.0400 43.5\n0.0025 11.4\ndifference 0.0375 difference 32.1\n3 (photosynthesis takes place so) oxygen produced, collects / stays, inside disc / on surface of disc ;\n4 disc, less dense / more buoyant / float ;\n\n6(b)(iii) 1 light intensity no longer limiting ; 2\n2 carbon dioxide concentration / temperature, now limiting ;\n© Cambridge University Press & Assessment 2026 Page 16 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 16 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-13-photosynthesis/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p16.png" ] }, { "id": "9700-2026-mj-44-q07", "question_id": "9700-2026-mj-44-q07", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 7, "topic": "Inheritance", "topic_slug": "9700-topic-16-inheritance", "marks": 10, "status": "available", "reason": null, "text": "7(a) symbols ; e.g. N = NF1 allele 4\nn = normal allele\nparents genotype Nn  nn\ngametes N n  n (n) ;\noffspring genotypes Nn (Nn) nn (nn) ;\noffspring phenotypes NF1 unaffected ;\n\n7(b) any three from: 3\nif test is negative\n1 removes worry / AW ;\nif test is positive\n2 early treatment ;\n3 helps plan for the future\nor\nmake informed decision whether to continue with pregnancy / family planning ;\n4 ref. to counselling ;\n5 discrimination / confidentiality / privacy ;\n6 false positive / AW ;\n© Cambridge University Press & Assessment 2026 Page 17 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n7(c) any three from: 3\nidea of\n1 no / less, resting membrane potential / stops Na+ K+ pumps from working ;\n2 no / less, action potential / depolarisation\nor\nno / less, (voltage gated) sodium (ion) / potassium (ion), channels opening ;\n3 no / less, impulse transmission / saltatory conduction / setting up of local circuits\nor\ndamages, myelin sheaths / Schwann cells ;\n4 no / less, synaptic transmission ;\n© Cambridge University Press & Assessment 2026 Page 18 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 17, 18 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-16-inheritance/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p17.png", "../answer-assets/9700_s26_ms_44-p18.png" ] }, { "id": "9700-2026-mj-44-q08", "question_id": "9700-2026-mj-44-q08", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 8, "topic": "Genetic technology", "topic_slug": "9700-topic-19-genetic-technology", "marks": 10, "status": "available", "reason": null, "text": "8(a) any three from: 3\n1 DNA (sample) ;\n2 primers ;\n3 (free) DNA nucleotides ;\n4 heat-stable DNA polymerase / taq polymerase ;\n5 buffer solution ;\n\n8(b) any seven from: 7\n1 denaturation at 90–98 C ;\n2 breaks hydrogen bonds (in DNA) ;\n3 to, produce single strands / separate the (two) strands ;\n4 annealing at 50–65 C ;\n5 (so that) primers, anneal / bind, (ss)DNA / complementary bases ;\n6 extension / elongation, at 65–75 C ;\n7 Taq polymerase binds to primer\nor\nprimer provides, binding site / starting point, for Taq polymerase ;\n8 Taq polymerase joins, (free) nucleotides / dNTPs, (to single strands) ;\n9 to synthesise, complementary / doubled stranded / new, DNA ;\n© Cambridge University Press & Assessment 2026 Page 19 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 19 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-19-genetic-technology/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p19.png" ] }, { "id": "9700-2026-mj-44-q09", "question_id": "9700-2026-mj-44-q09", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 9, "topic": "Control and coordination", "topic_slug": "9700-topic-15-control-and-coordination", "marks": 9, "status": "available", "reason": null, "text": "9(a)(i) any four from: 4\n1 H+ pumped out of, hinge / midrib, cells\nor\nH+ pumped into cell walls ;\n2 cell wall, loosens / cross-links broken ;\n3 calcium pectate dissolves ;\n4 Ca2+ enter cells ;\n5 water enters by osmosis ;\n6 cells, expand / become turgid ;\n7 (lobes) change from convex to concave ;\n\n9(a)(ii) idea that soil contains few, nitrates / (named) ions ; 1\n\n9(b) 4\nfeature nervous system endocrine system\nsignal impulse hormone ;\nhow neurone ; in blood\nsignal is transmitted\ntype of electrical chemical ;\ncommunication\nduration of short(er) long(er) ;\neffect\n© Cambridge University Press & Assessment 2026 Page 20 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 20 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-15-control-and-coordination/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p20.png" ] }, { "id": "9700-2026-mj-44-q10", "question_id": "9700-2026-mj-44-q10", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 10, "topic": "Energy and respiration", "topic_slug": "9700-topic-12-energy-and-respiration", "marks": 12, "status": "available", "reason": null, "text": "10(a) any four from: 4\n1 glucose phosphorylated (to form fructose (1,6) bisphosphate) ;\n2 fructose (1,6) bisphosphate splits ;\n3 (into) two, triose phosphate / TP ;\n4 (triose phosphate / TP) oxidised to pyruvate ;\n5 ATP / reduced NAD, produced ;\n\n10(b) any four from: 4\n1 fewer / no, acetyl groups combine with coenzyme A\nor\nless / no, acetyl CoA formed\nor\ndecrease in rate of / stops, link reaction ;\n2 fewer / no, acetyl CoA / acetyl group / acetate / 2C fragment, to combine with oxaloacetate ;\n3 decrease in rate of / stops, Krebs cycle ;\n4 decrease in / stops, production of, reduced NAD / reduced FAD ;\n5 (so) fewer / no, electrons pass along ETC ;\n6 decrease in / stops, oxidative phosphorylation / substrate-linked phosphorylation / ATP production ;\n© Cambridge University Press & Assessment 2026 Page 21 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n10(c) labels to: 4\nA – ATP synthase ;\nB – inner membrane ;\nC – intermembrane space ;\nD – left hand carrier ;\n© Cambridge University Press & Assessment 2026 Page 22 of 22\nTrace ID: PC-C13BFDE7F5\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/4a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/44 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 21, 22 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_44.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-44.pdf?download=1", "html": "9700-topic-12-energy-and-respiration/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_44-p21.png", "../answer-assets/9700_s26_ms_44-p22.png" ] }, { "id": "9700-2026-mj-51-q01", "question_id": "9700-2026-mj-51-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 17, "status": "available", "reason": null, "text": "1(a)(i) direction 1 mark as prose\n(drop of coloured liquid will move) left / AW allow (move) towards, O. asellus / test-tube / AW\nignore move towards respirometer\nand if nothing on answer line, check diagram and allow\ncorrect arrow / annotations on Figure 1.2\nexplanation\n(oxygen used in respiration) decreases / AW, volume / pressure (of ignore ref. to capillary action\ngas in respirometer) ; ignore volume / pressure is low (needs to be lower)\nA ‘a negative pressure is created’\n\n1(a)(ii) idea of replace (live) O. asellus with: 1 allow woodlouse / woodlice / asellus / invertebrate /\nanimal / organism as AW for O. asellus (shown in\nsterile / inert / glass / plastic / AW, beads ; Figure 1.2)\nor\ndead / AW, O. asellus ignore respirometer with no O. asellus\nR if change another factor in addition to O. asellus\n© Cambridge University Press & Assessment 2026 Page 8 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(iii) any six from: 6 ignore ref. to control experiment\nallow woodlouse / woodlice / asellus /\ninvertebrate / animal / organism as AW for O. asellus\n1 use a minimum of five stated temperatures ; 1 temperatures must include 5°C and 35°C, but\ndo not need to be evenly spaced\nmust see units at least once\nignore temperatures outside the range\n2 suitable method to maintain a constant temperature ; 2 A water-bath / incubator\nignore temperature-controlled room / air\nconditioning / heater / fridge\nA ref. to use thermometer and ice / warm water\n(in a beaker)\nR Bunsen burner\nmp3, 4 & 6 allow\nstandardised / controlled / fixed / constant as AW for\nsame\nignore known\n3 use, same / stated, mass of, sodium hydroxide / NaOH (pellets) ; 3 ignore amount / number, of NaOH pellets\nignore volume / concentration\nallow any value for mass if stated\n4 use, same / stated, number / amount / mass, of O. asellus 4 ignore size / length / volume / concentration, of\nor O. asellus\nuse, same / stated, age of O. asellus ; ignore same species / type / sex (of O. asellus)\nallow any value for number / mass if stated\nignore O. asellus (collected / bought) from\nsame, environment / population / supplier\nignore same, food source of O. asellus (before\ninvestigation)\n© Cambridge University Press & Assessment 2026 Page 9 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(iii) 5 method to, equilibrate / acclimatise, O. asellus ; 5 A leave O. asellus (in respirometer), in water-\nbath / at a set temperature, for, set / stated, time\nif stated, minimum time 5 minutes\n6 at each temperature, measure the distance (moved by the drop 6 allow note / record as AW for measure\nof coloured liquid), in a, set / stated, time ignore calculate as AW for measure\nor allow length / mm / cm as AW for distance\nat each temperature, measure the time (for the drop of coloured ignore known time (in question stem)\nliquid), to travel a, set / stated, distance ; allow ‘how far’ as AW for distance\nallow ‘how long’ as AW for time\nignore ref. to measuring without sodium\nhydroxide\nallow measuring the initial and final distance\nallow any value for distance / time if stated\ndo not allow measuring distance and time if\nneither is set / stated\n7 for each temperature, take at least three measurements ; 7 ignore calculate a mean\nA three replicates / repeat 2 times, at each\ntemperature\n8 safety comment with hazard and risk and precaution ; 8 ignore low / medium / high, risk\nR no risk\nhazard risk precaution\nignore heat / temperature / hot water as hazard\nignore irritant / toxic / burns as risk for sodium\nsodium hydroxide corrosive / caustic / (wear) gloves / goggles\nhydroxide\n(pellets) damage to eyes / safety glasses / PPE\nignore irritant / toxic as risk for O. asellus\nO. asellus allergy / biohazard (wear) gloves / PPE\n/ woodlouse / pathogens\n/ infection\n© Cambridge University Press & Assessment 2026 Page 10 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(iv) distance (in mm) 1 allow d / h / l for distance\nand allow t for time\nmultiplied by,  r2 / area (of glass tube cross-section) allow over time / multiply by 1/t, as AW for divide by\nand time\ndivided by time (in minutes) ; ignore per as AW for divided (in question stem)\nignore units if stated\nA d  r2 / t\nr = radius of glass tube\nallow  d2 / 4 =  r2 (where d = diameter)\n\n1(b)(i) (different / type of) respiratory substrate (solutions) ; 1 A (20%) glucose and (20%) maltose (solutions)\nA (different / type of) sugar (solutions)\nR concentration of, glucose / maltose / sugar\n(solutions)\n\n1(b)(ii) add 4 cm3, (50%) stock (solution of glucose) to, 6 cm3, distilled 1 allow ml as AW for cm3\nwater ; allow (50%) glucose (solution) as AW for stock\nsolution\nallow deionised / pure, water as AW for distilled\nwater\nignore water unqualified\nignore C V = C V\n1 1 2 2\nA use 4 cm3 stock solution and top up to 10 cm3,\nwith distilled water\n© Cambridge University Press & Assessment 2026 Page 11 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(iii) any two from: 2 ignore volume of yeast suspension\nignore volume / concentration, of, respiratory\nsubstrate / glucose / maltose / sugar, solution\nignore time\nignore light intensity\nignore carbon dioxide / oxygen, concentration\n1 concentration of yeast / mass of yeast (in suspension) ;\nR type of respiratory substrate\n2 species / variety / type / age / AW, of yeast ; R volume of gas\n3 temperature ; 3 R temperature that (solutions / AW) were boiled\nat\n4 pH ;\n5 size of (small) test-tube ;\n\n1(c)(i) type of data: 1 ignore categoric / qualitative / independent (as these\nnominal / discontinuous ; are types of variable)\nR quantitative / continuous / interval / ordinal\n/ discrete / dependent\n© Cambridge University Press & Assessment 2026 Page 12 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(c)(ii) (mean) volume (of gas collected after 30 minutes), is, greater / AW, 1 allow rate of, fermentation / (anaerobic) respiration,\nwith, glucose (than with maltose) / ora as AW for volume (of gas)\nand ignore (glucose is) better / AW\ndata quote (from Figure 1.5) ;\ndata quotes:\ncandidates should give data quotes for glucose and\nmaltose or the calculated difference.\nneed units at least once\nallow ml as AW for cm3\nrespiratory substrate volume of gas / cm3\nglucose 1.85 to 1.90 (e.g. 1.875)\nmaltose 1.45\ncalculated difference 0.40 to 0.45\n(e.g. 0.425)\n© Cambridge University Press & Assessment 2026 Page 13 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(c)(iii) any two from: 2 ignore easier / more efficient\nignore harder / more difficult\nignore spelling of underlined words if it is clear what\nis meant\n1 maltose, is a disaccharide / is not a monosaccharide, and needs 1 allow broken down / digested / converted (to\nto be hydrolysed (into glucose) glucose), as AW for hydrolysed\nor ignore glucose is, broken down / AW\nglucose, is a monosaccharide / is not a disaccharide, and does ignore glucose is, easier / AW, to break down\nnot need to be hydrolysed ; ignore maltose is, harder / AW, to break down\n2 idea that only glucose enters, glycolysis ; ora 2 A maltose cannot enter glycolysis (unless it has\nbeen broken down)\nignore respiration unqualified\n3 idea that entry of glucose into yeast cells is faster ; 3 A more glucose transporters available in yeast\ncells (than maltose transporters)\nA idea that gene expression for maltose,\ntransporter / enzyme / maltase / AW, takes time\n© Cambridge University Press & Assessment 2026 Page 14 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8, 9, 10, 11, 12, 13, 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-51.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_51-p08.png", "../answer-assets/9700_s26_ms_51-p09.png", "../answer-assets/9700_s26_ms_51-p10.png", "../answer-assets/9700_s26_ms_51-p11.png", "../answer-assets/9700_s26_ms_51-p12.png", "../answer-assets/9700_s26_ms_51-p13.png", "../answer-assets/9700_s26_ms_51-p14.png" ] }, { "id": "9700-2026-mj-51-q02", "question_id": "9700-2026-mj-51-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 13, "status": "available", "reason": null, "text": "2(a)(i) any two from: 2 ignore comparing / difference, between (two) means\n(in question stem)\n1 ignore quantitative data\n1 (data is) continuous ; R discrete / discontinuous / categoric / nominal /\nqualitative, data\n2 (data is) normally distributed ;\n3 standard deviations are (approximately) the same ;\n4 A 11 birds of song type A and 13 birds of song\n4 fewer than 30, values / birds / AW (for each song type) ; type B\n\n2(a)(ii) there is no, difference, in the (mean) bill length, between, (male) 1 allow birds / finches / males, as AW for\nG. conirostris (with song) type A, and (male G. conirostris with song) G. conirostris\ntype B ; allow beaks as AW for bills\nignore significant\nignore (mean) mass\nignore (mean) bill, depth / width\nR no, correlation / relationship / association\nR female (G. conirostris)\n\n2(a)(iii) 22 ; 1 11 + 13 – 2 = 22\n© Cambridge University Press & Assessment 2026 Page 15 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(a)(iv) 3 check Table 2.2 and answer for 2aiii\necf all mp for incorrect df / NR in 2aiii\n1 ignore t-value unqualified (could be the\n1 calculated (t-) value / 3.768, is greater than, 2.074 (critical value calculated or critical values)\nat df = 22 and p = 0.05) ; ora need to state correct critical value (for their df)\nallow correct critical value from table\n(circled / underlined etc)\nmp 2 & 3 ecf incorrect critical value to max 2\n2 R null hypothesis is accepted\n2 null hypothesis / H , is rejected ;\n0\n3 R correlation / relationship / association\n3 A greater than 95% probability that the\n3 there is a significant difference ;\ndifference (between the means) is not due to\nchance / is significant\nor\nless than 5% probability that the difference\n(between the means) is due to chance / is not\nsignificant\n© Cambridge University Press & Assessment 2026 Page 16 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(b) 2 allow bird / finch as AW for G. conirostris\nignore repeats / do a statistical test\neach food source = prickly pear and palo santo tree\n(or several different sources)\n1 measure / AW, time spent, feeding / eating / AW, on each food 1 allow note / record / calculate as AW for\nsource ; measure\nallow ‘how long’ as AW for time\nignore observe time for mp1\nignore time at location (needs to be time spent\neating)\nignore calculate, percentage / proportion (of\ntime)\nany one from:\nINTERNAL MAX\n2 idea of method to identify, individual / song type, (male) 2 allow use of, rings / paint / markings to identify,\nG. conirostris ; individual / song type\nignore listen unqualified\n3 idea of method to observe (feeding of male) G. conirostris on 3 allow lab-based or field-based methods\neach food source ; do not accept ref. to birds with only one food\nsource (birds must have a choice of food\nsources)\nA natural habitat (with both food sources) and\nobserve\nA feeding stations with both food sources and\nobserve\nA cage / AW, containing both food sources and\nobserve\nA camera / AW (to observe), birds (feeding) on\nboth food sources\n© Cambridge University Press & Assessment 2026 Page 17 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(c) any four from: 4 allow bird / finch as AW for G. conirostris\nallow beak as AW for bill\nignore ref. to different islands / allopatric speciation\n1 & 2 allow population / types as AW for groups\nsupports the conclusion: R ref. to (two) species (penalise once and ECF)\n1 idea that different groups (of G. conirostris) would have different 1 different / two, groups = song type A and song\nselection pressures ; type B / different bill lengths\nignore (changing) allele frequencies unqualified\nallow description of selection pressure:\ne.g. A (male) G. conirostris with different bill\nlengths are adapted to feed on different food\nsources\ne.g. A female G. conirostris will select one song\ntype of male G. conirostris for mating\n2 idea that differences between the two groups (of G. conirostris) 2 & 3 allow separation as AW for isolation\nwill lead to, reproductive / genetic / behavioural / ecological,\nisolation ;\n3 there is no geographical separation ; ora 3 A ora same geographical location\nA no physical barrier\nA geographical ranges (of the two groups)\noverlap\nextend the investigation: ignore improvements to the original investigation\nignore repeat investigation unqualified\nignore repeat, in different seasons / at different\ntimes of the year\nignore study a larger sample\nignore do a statistical test\n4 study female (G. conirostris) ;\n© Cambridge University Press & Assessment 2026 Page 18 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(c) 5 idea of studying (G. conirostris) for several generations ; 5 ignore longer time unqualified\nallow many / multiple as AW for several\nallow several years\nif stated, allow 3 or more years as AW for\nseveral years\n6 use DNA analysis / AW ; 6 allow DNA sequencing / DNA profiling / genetic\nfingerprinting / genetic screening\n© Cambridge University Press & Assessment 2026 Page 19 of 19\nTrace ID: PC-B925341256\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a1 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/51 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 15, 16, 17, 18, 19 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_51.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-51.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_51-p15.png", "../answer-assets/9700_s26_ms_51-p16.png", "../answer-assets/9700_s26_ms_51-p17.png", "../answer-assets/9700_s26_ms_51-p18.png", "../answer-assets/9700_s26_ms_51-p19.png" ] }, { "id": "9700-2026-mj-52-q01", "question_id": "9700-2026-mj-52-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 20, "status": "available", "reason": null, "text": "1(a) ref. to hazard and risk and precaution ; 1 mark as prose\nignore any other hazard\nignore low / medium / high, risk\nhazard risk precaution\nR no risk\nallow cut away from body\nknife / blade / scalpel cuts / injury cut away from the hand\nignore cuts clothing / AW ;\n/ AW (skin / hand or\nignore gloves as precaution for knife\n/ AW) cut onto a, board / tile / AW\nignore glasses / goggles\nignore biohazard\navocado / catalase allergy (wear) gloves / PPE\nignore hydrogen peroxide harmful\n/ enzyme / mesocarp / irritant\nignore damage / (chemical) burns\nhydrogen peroxide irritant / toxic (wear) gloves / goggles / safety\n/ H O / corrosive glasses / PPE\n2 2\n/ caustic\n/ damage to\neyes\n\n1(b)(i) time / days, after picking / after harvesting / to ripen 1 ignore ripeness / time, unqualified\nor\nlevel / degree / stages / AW, of ripeness ; allow different as AW for level\nignore age ;\nA colour of skin\nA softness of avocado / mesocarp\nignore softness of skin\n© Cambridge University Press & Assessment 2026 Page 8 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(ii) 7 ignore ref. to control experiment\nignore ‘known’ for ‘same’ then ecf if\nrepeated throughout\nallow\nstandardised / controlled / fixed / constant\nA mesocarp as AW for avocado\n1 use of five different (stages)/AW of ripeness ; 1 A method to obtain 5 stages of\nripeness\nallow if 5 different levels of ripeness\nstated even if less than 5 descriptions\ngiven – allow the mark\nignore age\nany six from:\n2 same / stated / fixed, dimensions of avocado pieces ; 2 ignore removal of skin\nignore size / mass / volume / SA for\ndimensions\nA cube with same / stated, dimensions\n/ linear measurement(s)\nignore length and width being the same\nunless ‘cube’ is mentioned\ncube 2 cm  2 cm – BOD\nignore any stated dimensions larger than\n10 cm\nA cylinders same length and diameter\n(if numbers stated need to see units at\nleast once)\n3 use knife / blade / scalpel / AW and ruler / AW (to cut the avocado pieces) 3 allow cutter as AW for knife\nor allow vernier calipers as AW for ruler\nuse knife / blade / AW and cork-borer and ruler (to cut cylinders) ;\n© Cambridge University Press & Assessment 2026 Page 9 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(ii) 4 use same, species / type / variety, of avocado 4 A Persea americana as same species\nor A same tree\nuse same number / amount of pieces (in each beaker) ; A all pieces cut from same avocado\nA one/ a / the piece\n5 use a suitable method to maintain a constant temperature of hydrogen 5 suitable methods:\nperoxide ; water-bath\ntemperature-controlled room\nA air conditioning / heater, set at one\ntemperature\nignore incubator / air conditioning\nunqualified\nif stated, temperature between 10 °C to\n40 °C\n6 use same / stated, volume / concentration of hydrogen peroxide / H O ; ignore concentration or volume values\n2 2\n7 avocado added / AW to hydrogen peroxide and immediately start timer ; allow ‘and then’ as AW for immediately\n8 suitable method / apparatus for measuring the quantity of oxygen 8 A gas as AW for oxygen\nproduced / released ; ignore count bubbles unqualified\nallow:\ncounting bubbles using camera\nadd washing up liquid and measure\nheight of foam produced\ncollect oxygen over water / H O and\n2 2\nmeasure volume in inverted\nmeasuring cylinder\n© Cambridge University Press & Assessment 2026 Page 10 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(ii) collect oxygen and measure volume in\na gas syringe ignore syringe\nallow measuring loss of oxygen by loss\nin mass, using an electric balance and\nmass change calculated\n9 at each stage / AW of ripeness, set / measure / record / fixed period of, time allow idea of recording time to sink\n(linked to release of oxygen) ;\n10 at each stage of ripeness take at least three measurements ; 10 ignore calculate a mean\nA three replicates / repeat 2 times, at\neach stage / AW of ripeness\n11 fresh / new / change / AW, hydrogen peroxide used in each\nexperiment / different stages/AW of ripeness ;\n\n1(c)(i) any suitable method of generating random numbers and matching to the 1 e.g. number all the trees and use a\ntrees ; random number generator (to select the\ntrees)\nignore quadrats / co-ordinates\n\n1(c)(ii) idea of to reduce the water loss from the avocados (while in storage) / AW ; 1 A reduces transpiration\nA reducing water evaporation\nallow no / stop / prevent AW for reduces\nallow losing moisture\nignore ‘keep moist’\nignore vapour\nignore prevent drying out\nignore ref. to osmosis\n\n1(c)(iii) 822  412 and 736  358 ; 1\n© Cambridge University Press & Assessment 2026 Page 11 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(c)(iv) correct plotting of both bars (within ½ square) ;; 2 ecf for incorrect calculations from 1(c)(iii)\n1 mark per bar if lines are thick or slanted take reading\nfrom top edge of bar\ngroup expected range\n20dR 410–1234\n30dR 378–1094\n© Cambridge University Press & Assessment 2026 Page 12 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(c)(v) any four from: 4 ignore units if seen\nmp2 only valid if mp1 has been awarded\nmp4 only valid if mp3 has been awarded\nignore ref. to dR\n1 conclusion 0d compared with 10 –30d or between 10 –30d\neffect of (cold storage only on catalase activity) is, variable / increases and\n0d 571 10d and 20d\ndecreases / fluctuates / no pattern / trend ;\n615 and 455\n2 data comparison with 0d and 10 / 20 / 30d\n0d 571 10d and 30d\ndata from 3 to show fluctuations, 0d / 571 or 10d / 615 or 20d / 455 or\n615 and 550\n30d / 550 ;\n0d 571 20d and 30d\n3 conclusion 0d / all d with all dR\n455 and 550\nincreased (mean) activity when allowed to ripen / dR (bigger than d)\nor\nconclusion all dR compared to 0d allow dR as AW for ‘time to ripening’\nall, dR data / storage times, with ripening have greater (mean) activity than, allow stored at 7 degrees / AW for d\n0d / ora ; allow stored at (7 and) 20 degrees / AW\nfor dR\n4 data comparison d with dR\ndata to compare 10d with 10dR or 20d with 20dR or 30d with 30dR 4 ignore means of all d and all dR ;\ne.g. 20d 455 v 20dR 822\nor A calculated difference between means\ndata to compare 0d / 571 with 10dR / 642 and 20dR / 822 and 30dR / 736\n5 error bars overlap (so may be) no significant difference (in catalase allow (95%) confidence\nactivity) between, all / both, groups / in Figure 1.4 / AW ; intervals / CI / SE / standard error as AW\nboth = all d data and dR for error bars\nignore the size of error bars / SE / CI\nignore optimum and highest mean\nactivity\nA both groups for all groups\nR results\nignore values\n© Cambridge University Press & Assessment 2026 Page 13 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(c)(vi) any two from: 2 R data is, not continuous / discrete\n/ discontinuous / categoric / qualitative\n(data) not normally distributed ;\nignore data is, continuous / quantitative\nstandard deviations are different ;\nA comparing 7 means\nmore than two means (to compare) ;\nignore fewer than 30 values\n© Cambridge University Press & Assessment 2026 Page 14 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8, 9, 10, 11, 12, 13, 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-52.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_52-p08.png", "../answer-assets/9700_s26_ms_52-p09.png", "../answer-assets/9700_s26_ms_52-p10.png", "../answer-assets/9700_s26_ms_52-p11.png", "../answer-assets/9700_s26_ms_52-p12.png", "../answer-assets/9700_s26_ms_52-p13.png", "../answer-assets/9700_s26_ms_52-p14.png" ] }, { "id": "9700-2026-mj-52-q02", "question_id": "9700-2026-mj-52-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 10, "status": "available", "reason": null, "text": "2(a)(i) (use an) identification key / app / expert ; 1 ignore photographs unqualified\nA (guide) book / AI / database\nignore features – spots / colouring /\npatterns\n\n2(a)(ii) any two from: 2\naccept any stated length of transect\n1 length of (belt) transect ; ignore width / size / orientation of belt\ntransect\n2 same / one, person counting (the butterflies on one transect) ;\n3 time of the day ; ignore weather\n4 time of the year / season / month ; ignore time unqualified\n5 (period of) time spent counting ;\n© Cambridge University Press & Assessment 2026 Page 15 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(a)(iii) any three from: 3 ignore human error\nmiscounting: AW for miscounting – inaccurate\n1 butterflies can fly so difficult to count / move from place to place therefore numbers / incorrect numbers / counting or\nmay counted more than once / could miss some ; recording, higher / lower, numbers\n/ counting more than once / missing some\n2 butterflies maybe, small / camouflaged, so difficult to see so, inaccurate (BOD – without ref. to counting or\ncount /miss some ; numbers)\nallow inaccurate results for inaccurate\n3 difficult to judge 2.5 m distance leading to inaccurate numbers ; numbers\n4 person sampling maybe walking too fast so could miss some ;\nmisidentifying:\n5 butterflies, can fly / maybe (very) small, therefore unable to see, AW for misidentification –\nfeatures / patterns, so inaccurate identification / difficult to identify ; inaccurate / incorrect identification / hard\nto identify, wrong identification\n6 some butterflies have similar, colours / patterns, so could misidentify ;\n7 person sampling may, lack the knowledge / AW, so could misidentify ;\n8 person sampling may not be able to, see clearly / AW, so could misidentify;\n9 person sampling may be walking too fast so could misidentify ;\n© Cambridge University Press & Assessment 2026 Page 16 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(b) 2 ignore predators / pollution\nprediction\nignore light\nignore selection pressures\nrural / farmland urban / towns and\nand woodland cities\n1 ignore greenery\n1 food / plants / flowers more… less…\nvegetation variety of.. less variety of ..\n2 habitats / niche / trees more less\n3 gardens / parks less more\n4 active conservation of less/more more / less\nbutterflies qualified\n5 pesticides qualified less/more less / more\n6 habitat fragmentation less more\n7 temperature colder warmer\n\n2(c) max 1 (mp2 only) if correct answer with no working shown 2 no ecf for incorrect working\nallow alternative method:\n1 correct working: % calculated –100\n(13 500 – 2300) ÷ 2300 (100)\nor ecf\n11 200 ÷ 2300 (100) ; incorrect values taken from the graph\nand\nall three figures shown correct formula\nand\ncorrect answer from their figures\n2 correct answer / 487 (%) ; R if not 3 significant figures\n© Cambridge University Press & Assessment 2026 Page 17 of 17\nTrace ID: PC-8AD397FDC6\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a2 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/52 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 15, 16, 17 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_52.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-52.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_52-p15.png", "../answer-assets/9700_s26_ms_52-p16.png", "../answer-assets/9700_s26_ms_52-p17.png" ] }, { "id": "9700-2026-mj-53-q01", "question_id": "9700-2026-mj-53-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 19, "status": "available", "reason": null, "text": "1(a)(i) 1 correct axis labels ; 3 e.g. x-axis = temperature\ny-axis = rate of respiration\n2 line rises and then falls ;\nignore anaerobic / aerobic\n3 line rising at an increasing rate to the optimum ; 3 ignore absence of fall\naccept any curve with an increasing\ne.g. three marks for: gradient\nmp2 and mp3 ignore starting point of\ncurve\necf for incorrect mp1 with correct axes\nlabels\n© Cambridge University Press & Assessment 2026 Page 8 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(ii) any eight from: 8\nany eight from:\n1 use a minimum of five stated temperatures ; 1 temperatures must include 10 ºC\nand 50 ºC\nmust see units at least once\n2 suitable method to maintain a constant temperature ; ignore temperatures outside the\nrange\n2 A water-bath / incubator\nignore temperature-controlled\n3 use, same / stated, number / amount / mass, of seeds ; room / air conditioning / heater / fridge\nA ref. to use thermometer and\nice / warm water\n4 use, same / stated, species / type / variety, of seeds ;\n4 Ignore age (of seeds)\n5 use, same / stated, volume / concentration, of sodium hydroxide / NaOH ; 5 Ignore mass / amount\nmp3, mp4 and mp5 allow\nstandardised / fixed / controlled\n/ constant as AW for same\nignore known\n6 method to, equilibrate / acclimatise, seeds to new temperature ; 6 A leave seeds in respirometer at\nnew temperature / in water-bath / AW,\nfor, set / stated time\nif stated, minimum time 5 minutes\n7 at each temperature, measure the distance (moved by the coloured liquid), in 7 allow note / record as AW for\na, set / stated, time measure\nor ignore calculate as AW for measure\nat each temperature, measure the time, (for the coloured liquid), to travel a, allow length / mm as AW for distance\nset / stated, distance ; ignore ref. to measuring without\nsodium hydroxide\n© Cambridge University Press & Assessment 2026 Page 9 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(ii) allow how far as AW for distance\nallow how long as AW for time\nignore collecting gas in the syringe\nignore ref. to open / close, tap\n8 (replace seeds / repeat, with) sterile/ inert / glass / plastic / AW, beads 8 ignore respirometer with no seeds\nor R if another variable is changed as\ndead / AW, seeds ; well as the seeds\n9 at each temperature, take at least three measurements ; 9 ignore calculate a mean\nA three replicates / repeat 2\ntimes / multiple times, at each\ntemperature\n10 safety comment with hazard and risk and precaution ; 10 ignore burns\nignore biohazard\nignore hot water as a risk\nhazard risk precaution\nNaOH / sodium irritant / corrosive / caustic (wear) gloves / safety\nhydroxide / damage to eyes glasses / goggles\n/ PPE\nseeds irritant / allergy (wear) gloves / PPE\n11 Idea of: open the tap and use the syringe to reset the coloured liquid ;\n© Cambridge University Press & Assessment 2026 Page 10 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(a)(iii) any four from: 4\n1 divide diameter by 2 (to give radius)\nor\nradius = 0.5 mm ;\n2 calculate (cross sectional) area (of the capillary tubing) 2 A r2 or d2 / 4\nor Use calculation guidance\narea = 0.79 mm2 ;\n3 distance multiplied by (cross sectional) area (to calculate volume of gas) ; r2  distance moved gets mp2 and\nmp3\n4 divide by time ;\n5 calculate a mean distance / rate ;\n6 divide by mass of seeds used ;\n\n1(b)(i) 0.846 ; 1 use calculation guidance\nA 0.85\n\n1(b)(ii) (species =) B ; 2 No ecf from 1(b)(i)\n(evidence =) carbon dioxide (volume) is greater than oxygen (volume) ; ora A RQ is greater than 1\nNo ecf for wrong species\n\n1(b)(iii) any one from: 1 ecf for species C only in 1(b)(ii)\nreason why oxygen measurements are too low\nignore human error unqualified\n1 (water bath) temperature was too low ; A temperature was high and enzymes\n2 duration of the test, was too short / less than one minute ; denatured\n3 idea of gas escaping from, respirometer / apparatus / AW ;\nR gas coming into apparatus\n© Cambridge University Press & Assessment 2026 Page 11 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8, 9, 10, 11 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-53.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_53-p08.png", "../answer-assets/9700_s26_ms_53-p09.png", "../answer-assets/9700_s26_ms_53-p10.png", "../answer-assets/9700_s26_ms_53-p11.png" ] }, { "id": "9700-2026-mj-53-q02", "question_id": "9700-2026-mj-53-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "2(a) independent variable: 2\nnumber / amount of (daily) garlic capsules ;\ndependent variable:\n(resting systolic) blood pressure ;\n\n2(b) capsule with no garlic ; 1 ignore ‘placebo’ unqualified\nA placebo capsule\nallow tablet / pill, as AW for capsule\nA capsule with,\nsugar / starch / cellulose / AW, (and no\ngarlic)\n\n2(c)(i) continuous ; 1 ignore quantitative / ordinal / ordered /\ndependent / interval / normally\ndistributed\nR qualitative / categoric / discrete\n/ discontinuous / nominal\n© Cambridge University Press & Assessment 2026 Page 12 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(c)(ii) any three from: 3 ignore improved blood pressure as\nAW for blood pressure decreases\ncomparing start to end of the investigation\n1 (resting systolic) blood pressure decreased in all groups (over the 12 weeks) ;\n2 SE for, start / 0 weeks and end / 12 weeks, do not overlap, therefore (mean\nresting systolic blood pressure may be) significantly different (in all groups) ; 2 allow if only one group is stated\nignore standard deviation / 95%CI /\ncomparing groups error bars\n3 results / decrease in blood pressure, for 1 garlic capsule were not different to allow significant, decrease / AW\nthe control ; (implies a difference)\n4 SE for one garlic capsule and control, overlap (at all times) therefore (mean allow is significantly different\nresting systolic blood pressure) is not significantly different ; ignore ‘results are significant’\n4 ignore standard\n5 results / decrease in blood pressure, for 2 and 4 garlic capsules were different deviation / 95%CI / error bars\nto the control allow is not significantly different\nor ignore no significant decrease\n(taking) 2 garlic capsules gives, greatest / AW, decrease in blood pressure ; ignore insignificant\n6 SE for, 2 garlic capsules and control, do not overlap (at 8 weeks and 12\nweeks) therefore (mean resting systolic blood pressure may be) significantly 6 ignore standard\ndifferent deviation / 95%CI / error bars\nor allow significant, decrease / AW\nSE for, 4 garlic capsules and control, do not overlap (at 8 weeks) therefore (implies a difference)\n(mean resting systolic blood pressure may be) significantly different ; allow is significantly different\nignore ‘results are significant’\n\n2(c)(iii) any two from: 2\nignore ref. to standard deviations\n1 (data) not normally distributed ; (because the SDs are approximately\nthe same)\nR standard deviations are\n2 four / more than two, means to compare ; different / data is not continuous\n3 more than one mean per group / means change over time ; ignore fewer than 30 values\n© Cambridge University Press & Assessment 2026 Page 13 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(d) any two from: 2 ignore repeat unqualified\n1 larger sample size / study more than 84 people ;\n2 longer investigation / study for more than 12 weeks ;\n3 standardise, age / sex / diet / smoking status / alcohol consumption / other 3 A exclude those already taking\nmedication taken / time of day capsule taken / AW ; meds for blood pressure\nignore ref. to take 3 garlic capsules\n4 measurements of diastolic blood pressure ;\n5 ref. to standardise measurement of blood pressure ; 5 A measure blood pressure, at same\ntime of day / at same location / same\nbody position\n© Cambridge University Press & Assessment 2026 Page 14 of 14\nTrace ID: PC-6F815CCF34\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a3 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/53 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_53.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-53.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_53-p12.png", "../answer-assets/9700_s26_ms_53-p13.png", "../answer-assets/9700_s26_ms_53-p14.png" ] }, { "id": "9700-2026-mj-54-q01", "question_id": "9700-2026-mj-54-q01", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 1, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "1(a) pigment 1: carotene ; 2\npigment 2: chlorophyll a ;\n\n1(b)(i) any eight from: 8 allow\nstandardised / controlled / fixed / constant\nas AW for same\nignore known\nallow:\ndirect sunlight = high light intensity\nshade = low light intensity\ncollect leaves from stinging nettles growing in direct sunlight and in the shade: ignore no light / dark as AW for shade\n1 method to select plants growing in direct sunlight and in the shade, using,\nrandom / systematic, sampling 1 should be 2 or more different plants\nor allow sample plants at,\nmethod to grow plants in direct sunlight and in the shade ; coordinates / grid / quadrats, chosen using\na random number generator\nallow sample plants at a fixed / set\ndistance along a, line / transect\nR throwing quadrats\nignore quadrants\nallow lab-based method to grow plants in\ndifferent light intensities (e.g. lamp at\ndifferent distances)\nignore ref to controlled variables\nignore ref to time (for growth) but R if less\nthan 24 hours\n2 collect / cut / AW, leaves (from plants growing) in direct sunlight and in the 2 allow if leaves are from (different parts)\nshade ; of same plant (in different light intensities)\n© Cambridge University Press & Assessment 2026 Page 8 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(i) 3 select leaves from, same / stated, position / part / AW, of plant ; 3 A apical leaf / same height from ground\nignore same species / type / variety\nignore size / number / age / colour, of\nleaves\nuse chromatography to separate the chloroplast pigments present in the\nleaves: 4 A use pestle and mortar / blender\n4 apparatus to grind leaves (to prepare leaf extract) / suitable description\nignore cutting (leaves)\nignore (use of) solvent / water\nignore filtering / centrifuge\nA roll coin across leaf (onto paper / TLC\nplate)\n5 use pencil (and ruler) to draw, origin / line / AW (on paper / TLC plate) ; 5 R pen / ink needs to be a method\n6 method to add a concentrated spot of leaf extract (to paper / TLC plate) ; 6 A use, capillary tube / melting point\ntube / pipette / glass rod / AW, to add leaf\nextract and repeat / reapply (to same\nposition)\n7 use, same / stated, solvent (for chromatography) 7 ignore solvent used for extraction\nor allow any named organic solvent\nuse, same type of (chromatography) paper / TLC plate ; R water and ecf\nignore concentration / volume\n8 add (chromatography) paper / (TLC) plate (with spot of leaf extract), to a 8 A from diagram\nbeaker / AW, of solvent allow chromatogram as AW for\nand paper / TLC plate\nensure solvent is below the, origin / line / AW ;\n© Cambridge University Press & Assessment 2026 Page 9 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(i) 9 remove, chromatogram / AW, from beaker / solvent, 9 allow paper / (TLC) plate as AW for\nwhen solvent front is close to top (of paper / TLC plate) chromatogram\nor allow solvent / front as AW for solvent front\nafter, set / stated, time ; ignore time if stated\n10 (use pencil to) mark position of solvent front (before the solvent\nevaporates) ; 10 A take photo of chromatogram\ncollect the data needed to identify each chloroplast pigment:\n11 use a, ruler / AW, to, measure / note / record / AW, distance (from origin) to\nsolvent front and distance (from origin) to, (each) spot / pigment / AW ;\n11 ignore calculate R / R formula\nf f\n12 idea of measure to the, centre / AW, of (each) spot of pigment ; unqualified\nignore ref. to repeats\n13 note / record / AW, colour of each spot of pigment;\n© Cambridge University Press & Assessment 2026 Page 10 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n1(b)(ii) hazard and risk and precaution ; 1 ignore low / medium / high, risk\nR no risk\nignore harmful unqualified\nhazard risk preca ution\nignore plants / stinging nettles / trichomes\nenvironment / getting lost / trip (wear protective)\nas hazard\nwoodland hazard shoes / clothes / PPE\nignore wearing gloves as a precaution\n/ gardens / injury\n/ farmland stay, in a group / with\nallow check yourself / immunise (as\n/ AW expert / ranger\nprecaution against ticks)\nuse GPS\nallow epipen as precaution for allergies\nanimals allergy / irritation / injur (wear protective)\nNOTE: allow away from body\ny shoes / clothing / PPE\nignore cuts clothing / AW\nignore cutting leaves / plant unqualified for\nstay, with expert / ranger\nhazard\npollen / spores allergy / irritation mask / goggles / PPE\nignore water as hazard\ntake, anti-histamines\nignore allergy / corrosive as risk for solvent\n/ hayfever medication\nknife / scalpel cuts / injury cut away from the hand\n/ AW (skin / hand / AW) or\ncut onto a, board / tile / AW\n(named) flammable no naked flames\nsolvent\nfumes / vapour: use fume cupboard / use\nirritant / toxic well-ventilated room / keep\ndamage to, containers covered / safety\nlungs / AW glasses / goggles / mask /\nPPE\n© Cambridge University Press & Assessment 2026 Page 11 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 8, 9, 10, 11 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-54.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_54-p08.png", "../answer-assets/9700_s26_ms_54-p09.png", "../answer-assets/9700_s26_ms_54-p10.png", "../answer-assets/9700_s26_ms_54-p11.png" ] }, { "id": "9700-2026-mj-54-q02", "question_id": "9700-2026-mj-54-q02", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 2, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 8, "status": "available", "reason": null, "text": "2(a) first experiment: 2 ignore rate of photosynthesis\nrate of oxygen production ;\nallow volume / number of moles / AW, of\nsecond experiment: oxygen produced, in a set time\ntime taken to change colour (from blue-green to green) / rate of DCPIP\nreduction ; ignore rate of NADP reduction\n\n2(b) any one from: 1 ignore light intensity / temperature\nignore volume (of solutions)\nignore ref to colour\nignore pH\nignore carbon dioxide\nignore stirring\nR concentration of sodium chloride\n1 mass / concentration, of A. doliolum (cells in suspension) ; 1 allow A.\ndoliolum / cells / Anabaena / prokaryote\n2 concentration of enzyme ; as AW for A. doliolum cells\nignore size\n3 time, in enzyme solution / for hydrolysis of cell walls ; 3 ignore time unqualified\nR time taken to change colour\n4 concentration of DCPIP ;\n\n2(c) idea that (enzyme partially hydrolysed the bacterial cell walls so): 1 ignore ref. to sodium chloride / NaCl\nignore ref. to NADP / H+\n(more) DCPIP can, diffuse / enter, cells ignore enter chloroplast\nor\ndiffusion / AW, of DCPIP (into cells) is, faster / AW\nor ignore easier\npermeability of cell wall increases ;\n© Cambridge University Press & Assessment 2026 Page 12 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(d) Table 2.1 completed with correct volumes ; 2 ignore decimals\nconcentration of volume of stock (volume) water ;\nignore working / C V = C V\nsodium chloride solution of sodium (/ cm3) 1 1 2 2\nsolution chloride\n/ moldm-3 / cm3\n0.25 10 10\n0.20 8 12\n0.15 6 14\n0.10 4 16\n0.05 2 18\n0.00 0 20\n© Cambridge University Press & Assessment 2026 Page 13 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n2(e) 2 ignore rate of photosynthesis unqualified\nignore first / second experiment\nallow NaCl as AW for sodium chloride\nallow peak / optimum / greatest / maximum\nas AW for highest\n1 highest / AW, (mean rate of) oxygen production is at a lower sodium ignore any comparison between y-axis\nchloride concentration than the highest AW, (mean rate of) DCPIP reduction ; values\nora ignore y-axis data quotes\nignore ref. to lines crossing\nignore comparisons between gradients of\nlines (e.g. fast decrease / slight decrease)\n2 highest / AW, (mean rate of) oxygen production is at 0.10 moldm–3 2 need units for concentration at least\n(sodium chloride) once\nand\nhighest / optimum / AW, (mean rate of) DCPIP reduction is at\n0.20 moldm–3 (sodium chloride) ;\n© Cambridge University Press & Assessment 2026 Page 14 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 12, 13, 14 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-54.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_54-p12.png", "../answer-assets/9700_s26_ms_54-p13.png", "../answer-assets/9700_s26_ms_54-p14.png" ] }, { "id": "9700-2026-mj-54-q03", "question_id": "9700-2026-mj-54-q03", "subject": "9700", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 3, "topic": "Planning, analysis and evaluation", "topic_slug": "9700-experimental-skills", "marks": 11, "status": "available", "reason": null, "text": "3(a) any two from: 2 allow fungus as AW for M. pingshaense\nallow A. coluzzii / Anopheles as AW for\nmosquitoes\nallow uninfected A. coluzzii as AW for\ncontrol\n1 (infection / treatment with) GM M. pingshaense, reduces / AW, the 1 ignore ref. to non-GM M. pingshaense\n(percentage of mosquitoes that) produce eggs ; ignore kills mosquitoes\n2 error bars for control and GM (M. pingshaense) do not overlap, 2 allow (95%) confidence\ntherefore (mean percentage of mosquitoes that produce eggs) is significantly intervals / CI / standard error bars as\ndifferent ; AW for error bars\nignore standard deviation / SE / standard\nerror unqualified\nallow significant, decrease / AW (implies a\ndifference)\nallow may be significantly different\nignore ‘results are significant’\n3 conclusion for non-GM M. pingshaense: 3 allow (95%) confidence intervals / CI\n/ standard error bars as AW for error bars\nerror bars for non-GM (M. pingshaense) and control overlap, therefore (mean\npercentage of mosquitoes that produce eggs) (may be) not significantly ignore standard deviation / SE / standard\ndifferent error unqualified\nor\nerror bars for non-GM (M. pingshaense) and GM (M. pingshaense) overlap, allow is not significantly different\ntherefore (mean percentage of mosquitoes that produce eggs) (may be) not ignore no significant decrease\nsignificantly different ignore insignificant\nor\nlarge / AW, error bar for non-GM (M. pingshaense) shows that\n(calculated / sample) mean is (likely to be) further from the, true / actual, mean\nor ignore data / results / values as AW for\nidea that error bar, for non-GM (M. pingshaense) are, large / AW, and the mean\nmean is less reliable ; ignore accurate / valid / precise\n© Cambridge University Press & Assessment 2026 Page 15 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n3(b)(i) idea of placing a, net / glasshouse / AW, over the experimental area ; 1 allow web / mesh\nignore (use) black fabric / curtain\nignore close doors / windows of hut\nignore insect repellent\nR insecticide\n\n3(b)(ii) 1. Table 3.2 completed and correct values of (O–E)2 / E ;\n2. (2 =) 2390 when rounded to 3 significant figures ;\n3. (2 =) 2390 ; must be to 3 significant figures\nrepeat O E O - E (O – E) 2\n© Cambridge University Press & Assessment 2026 Page 16 of 18\n( O −\nE\nE ) 2\n3 1. A as fractions / any decimal places\n2. correct value of 2 to 3 or more sig figs\nuse calculation guidance – give mp2 if\ntheir value of 2 rounds to 2390 (e.g.\n2389.5, 2389.4, 2389)\n2. and 3. allow ecf to max 2 from incorrect\n1 13 1396 –1383 1912689 1370.1 (O–E)2/E\n2 61 731 –670 448900 614.1\n3 12 429 –417 173889 405.3\ntotal: 2390\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n3(b)(iii) critical value: 1 allow critical value from table (e.g.\n5.991 (p = 0.05 and df = 2) underlined / circled)\nallow 9.210 (p = 0.01 and df = 2)\nand\nexplanation:\nyes / student was correct / reject null hypothesis / difference is significant allow ecf if incorrect 2\nand\ncalculated value / 2 / 2390, is greater than, critical value / 5.991 ; ora must give correct statistics for ecf:\ne.g. calculated value, is less than 5.991\nand null hypothesis is accepted / student is\nincorrect\n\n3(c) 4 allow fungus as AW for (GM) M.\nsupports the conclusion: pingshaense\nallow A. coluzzii / Anopheles as AW for\nusing Table 3.1: mosquitoes\n1 (total) number of, A. coluzzii / mosquitoes is, lower / AW, with (GM) M.\npingshaense ; ora 1 ignore ref. to egg production\n/ reproduction\n2 ignore reject null hypothesis\nusing calculated value of 2: A significant decrease\n2 there is a significant difference ; R correlation / relationship\nA less than, 5% / 0.05 / 1% / 0.01,\nprobability that, difference is due to chance\nA ora greater than, 95% / 0.95 / 99% / 0.99,\nprobability that difference is not due to\nchance\necf from incorrect 2\nA ecf there is no significant difference (if\ncalculated value of 2, is less than 5.991)\n© Cambridge University Press & Assessment 2026 Page 17 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/\n\n3(c) further information needed (max 3): ignore repeat investigation unqualified\nignore larger sample size\nignore do a control\nignore ref. to statistical test\nignore do investigation in other\nareas / countries\nignore ref. to cost\n3 ignore longer time unqualified\n3 carry out investigation in other years ; ignore carry out investigation in other\nseasons\n4 carry out investigation with other species of (Anopheles) mosquito ; 4 allow other types / varieties / AW, of\n(Anopheles) mosquito\n5 idea of checking if, (GM) M. pingshaense could be, harmful / toxic / AW, to 5 and 6 ignore (GM) M. pingshaense\nhumans ; could be harmful unqualified\n6 idea of checking if (GM) M. pingshaense could be harmful / toxic / AW, to,\nlivestock / ecosystems / biodiversity / (native) species / AW ;\n7 idea of checking if, A. coluzzii / mosquitoes, become resistant to GM M.\npingshaense ;\n8 idea of checking how long (GM) M. pingshaense survives (on the black 8 A checking how often (GM) M.\ncotton fabric) ; pingshaense should be applied (to the\nblack cotton fabric)\n© Cambridge University Press & Assessment 2026 Page 18 of 18\nTrace ID: PC-694F6C5F2D\nRe-uploading, mirroring or re-hosting this file on any other website or domain is unauthorised and traceable.\nLicensed for hosting on papacambridge.com only.\nP97a00p/5a4 CMaarkm Scbhermide gJuene 2·0 2p6 a| Spoaurccea: mpapbarciadmgbreid.gceo.comm 9700/54 Mark Scheme June 2026\nDownloaded from PapaCambridge - https://papacambridge.com/", "source_pages": [ 15, 16, 17, 18 ], "source_pdf": "_source-pdfs/2026-May-June/ms/9700_s26_ms_54.pdf", "source_pdf_url": "https://pastpapers.co/api/file/caie/a-level/biology-9700/2026-may-june/9700-biology-june-2026-mark-scheme-54.pdf?download=1", "html": "9700-experimental-skills/answers.html", "image_paths": [ "../answer-assets/9700_s26_ms_54-p15.png", "../answer-assets/9700_s26_ms_54-p16.png", "../answer-assets/9700_s26_ms_54-p17.png", "../answer-assets/9700_s26_ms_54-p18.png" ] } ] }