Answers to Biology long answer exam questions

Transcription

1 Jan 203 B Higher

2 Jan 203 B2 Higher

3 Jan 203 B2 Higher

4 June 202 B2 Higher

5 June 202 B2 Foundation

6 June 202 B2 Foundation

7 Jan 202 B Higher

8 Specimen B Higher

9 Specimen B Higher

10 Specimen B Higher

11 Specimen B Higher

12 Specimen B2 Higher

13 Specimen B3 Higher

14 Specimen B3 Higher

15 June 202 B2 Higher

16 B Higher June 203

17 B Higher June 203

18 B Higher June 203

19 B2 Higher June 203

20 B2 Higher June 203

21 B3 Higher June 203

22 B3 Higher June 203

23 B Questions from e-aqa M. receptor detects stimulus / sharp object impulse / information / message passes along sensory neurone to spinal cord from spinal cord along motor neurone to muscle muscle contracts [4] M2. gravity accept gravitropism / geotropism caused redistribution of auxin / hormone to lower side of stem these hormones stimulate growth of cells on the lower side of the stem only so the stem grows upwards [4] M3. (a) measles ignore mumps rubella accept German measles

24 (b) viruses are dead accept other viral treatments accept non-virulent mild must be qualified do not accept small dose (c) The answer to this question requires good English in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme. Maximum of 4 marks if ideas not well expressed any five from: contains antigens or proteins accept reference to immunological memory or memory cells white cells (accept lymphocytes) do not accept phagocytes idea of specificity in antibodies or antigens antibody production ignore engulfing antigens destroyed / virus destroyed rapid antibody production if infected max 5 (d) antibiotics do not kill / affect viruses [9] M4. (a) Quality of written communication:

25 ideas given in a sensible order broken down giving products (could be CO 2, minerals or gas) (used by trees) Q or Q any three from: microorganisms / bacteria / fungi / saprotrophs accept saprophytes / saprobionts / detritivores (named) digest / break down organic matter / leaves / decompose / reference decomposers / decay / rot use of enzymes / correct named example absorption by diffusion / active transport must be of breakdown products respiration / combustion release of carbon dioxide CO 2 can be used (by trees) in photosynthesis do not accept CO 2 taken in by roots 3 (b) any two from: warmth / suitable temperature do not accept heat / hot weather damp / water / rain / humid / moisture oxygen suitable ph 2 [6]

26 M5. mutation or description of mutation (gives resistance to penicillin) some survive (penicillin) (survivors) reproduce or multiply asexual reproduction or binary fission or cloning accept mitosis gene for resistance or the mutation is passed on (to offspring) allow reference to bacteria being immune ignore reference to survival of fittest [5] M6. (a) use antibiotics; or named one to kill bacteria; (not microbes) each for mark 2 (b) some ingest/digest bacteria (not microbes) OWTTE some produce antibodies; which destroy bacteria/viruses; some produce antitoxins; which counteract poisons released by bacteria each for mark 5 [7] M7. (a) (i) vole/small bird/beetle

27 (ii) gains mark oak trees are large organisms; therefore their biomass is large; but their numbers are small each for mark 3 (b) 8 of: energy stored in chemicals in cells/tissues/growth; passed up food chain; less energy stored at each stage in food chain/pyramid level; because only part of energy taken in used for growth; some lost in waste; some used for repair; used to main body systems; some lost in respiration; some converted into other forms of energy; e.g. movement; much lost as heat; by time detritus feeders have used remains; all returned to environment each for mark 8 c animals c2 decomposers 2 marks for sequencing and organising the information 2 [4] M8. (a) water oxygen gains mark gains mark 2 (b) e.g.: some materials/energy lost in animals waste materials

28 respiration releases energy some materials/energy used in maintenance/repair some energy used for movement much lost as heat to surroundings some organisms die (rather than eaten) reference to detritivors reference to microbes each for mark 8 [0]

29 B2 Long Answer from e-aqa M. (a) increased by about 7 times / from 600 to 4300 / by 3700 (b) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. No relevant content There is a brief description of at least two causes of extinction, which has little clarity and detail. 0 marks Level ( 2 marks) There is a description of some causes of extinction, including both small-scale and large-scale events but there is a lack of clarity and detail. Level 2 (3 4 marks) There is a clear, balanced and detailed description of at least five causes of extinction, including both small-scale and large-scale events. Level 3 (5 6 marks) examples of biology points made in the response: changes to the environment / named changes new competitors new diseases new predators volcanic eruptions collisions with asteroids [7] M2. (a) (genotype / gametes from P / father) D and d (*)

30 (genotype / gametes from Q / mother) d and d / accept d(*) offspring genotypes correctly derived from correct gametes(*) offspring phenotypes R and S identified (*) eg may be in punnett square allow own upper and lower case symbols or allow any symbol correctly used with key (b) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. No relevant content. There is a brief description of the issues involved in screening for at least one condition. 0 marks Level ( 2 marks) There is some description of issues involved in screening for both conditions but there is a lack of both pros and cons for the two conditions. Level 2 (3 4 marks) There is a clear, balanced and detailed description of the issues involved in screening for both conditions, giving pros and cons for each condition. Level 3 (5 6 marks) examples of biology points made in the response For cystic fibrosis pros: reduce number of people with cystic fibrosis (in population) reduce health-care costs allows decision / emotional argument, eg allows people to make choices about termination cons:

31 possible damage / risk to embryo / fetus / baby possible harm / risk to mother (may) have to make ethical / moral / religious decisions for polydactyly: cures disfigurement but condition not life threatening so risks to foetus / mother unjustified [0] M3. one mark for each of the following comparisons to a maximum of 6 candidates must make a clear comparison meiosis sexual gametes ovary or testes or gonads half number of chromsomes mitosis asexual growth all other cells same number of chromosomes haploid or diploid or 23 chromosomes 46 chromosomes reassortment or variation possible or not identical no reassortment or no variation or identical 4 cells produced 2 cells produced 2 divisions division [6]

32 B3 Long Answer from e-aqa M. (a) idea: more (fossil) fuel burned (do not credit simply more people/cars/industry) deforestation = less photosynthesis deforestation = more respiration/burning each for mark 3 (b) idea: climate change for mark warmer/colder/drier/wetter food production affected/starvation mayor ecosystems destroyed/damaged any two for mark each 6 sea level rise for mark low land flooded less food grown/starvation homes/factories flooded any two for mark each Allow polar ice caps melt sea water expands [9] M2. Quality of Written Communication mark for correct sequencing burning named gas correct environmental problem

33 any three from: coal / fossil fuel is burned (water vapour and carbon dioxide and) sulphur dioxide formed accept nitrogen oxides (gases) dissolve / react in rain accept dissolve / react in water vapour make acid rain damages trees accept harms plants or animals or damage to buildings makes rivers /lakes acidic accept carbon dioxide is a greenhouse gas / causes global warming for 2 marks 3 [4] M3. Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. No relevant content. 0 marks There is a brief description of at least one reason for deforestation or at least one effect of deforestation. Level ( 2 marks) There is a scientific description of the reasons for deforestation and an attempt at the effects of deforestation but the account is limited to either direct or indirect effect. Level 2 (3 4 marks) There is a clear and detailed scientific description of the reason for deforestation and effects on the environment. Level 3 (5 6 marks) examples of biology points made in the response

34 reasons for deforestation: timber land for agriculture roads and buildings land for biofuels effects of deforestation: reduction in biodiversity increase in carbon dioxide content of atmosphere global warming climate change rising sea levels changes in migration patterns [6]