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New AQA GCSE Science © Nelson Thornes Ltd 2011 1

1 25 °C – Used in school laboratory to grow microorganisms safely, 35 °C – Used in industrial laboratories to grow microorganisms quickly, 100 °C – Used to kill microorganisms

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2 Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. There is a clear, balanced and detailed description referring to both overeating and deficiency. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate or relevant specialist terms used accurately.

There is some description of a range of the ways in which the diet can be unbalanced and the effects. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of specialist terms has been attempted, but not always accurately.

There is a brief description of at least two ways in which the diet can be unbalanced, which has little clarity and detail. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of

understanding of their meaning. No relevant content.

Examples of biology points made in the response:

 balanced diet contains all the correct nutrients in the correct amounts  balanced diet has the correct amount of energy

 too much energy leads to mass/weight increase e.g. eating too much fat  if activity increases use of energy increases

 too little energy leads to decrease in mass/weight  can lead to anorexia/described symptom

 lack of vitamins/named vitamin can lead to deficiency  disease/correctly named

 too much carbohydrate/ sugar/overweight can lead to type 2 diabetes  lack of a mineral ion/named ion can lead to deficiency

 disease/correctly named

 obesity linked to e.g. heart disease/arthritis/high blood pressure, etc.

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3 a the rate of chemical reactions in cells 1

b Any one from:

• the proportion of fat to muscle • inherited factors

• other sensible suggestion, other than activity

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4 a i lives inside cells ii inactive

iii antibodies b i 1950

ii 8 (years)

iii Any one from: e.g.

• disease could be reintroduced (from abroad) • disease would spread back insufficient • disease would spread if it came back • protection on holiday abroad

• high proportion of immune people needed to prevent epidemic 1 1 1 1 1 1

5 a Any two from:

• resistant to (most) antibiotics

• contagious or easily passed on or reference to open wounds • patients ill therefore less able to combat disease

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b i chloride of lime/hand washing killed bacteria (picked up from corpses) allow disease/germs/infection/ disinfectants

ii people to wash hands after contact with patient so bacteria/ pathogen/MRSA not transferred to other patient

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New AQA GCSE Science © Nelson Thornes Ltd 2011 1

1 a i A ii C iii B

b i temperature/pressure/pain

ii idea of increased sensitivity (for a particular task, e.g. to feel a pencil when writing)

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2 a reflex

b prevents damage/harm OR prevents skin burning

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3 a response

b any one of: touch/pressure/chemical

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4 a Auxin links to plant stems and roots, oestrogen links to ovary, FSH links to pituitary gland. b i FSH ii oestrogen 3 2 5 a i reflex ii phototropism

b There is a clear and detailed scientific description of phototropism and geotropism and how auxin controls growth of both the root and shoot. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer shows very few errors in spelling, punctuation and grammar.

There is some description of how hormones cause the root and shoot to bend. The answer has some structure and the use of specialist terms has been attempted, but not always accurately. There may be some errors in spelling, punctuation and grammar.

There is a brief description of how hormones control growth in either the root or shoot which has little clarity and detail. The answer is poorly

constructed with an absence of specialist terms or their use demonstrate a lack of understanding of their meaning. The spelling, punctuation and grammar are weak.

No relevant content.

Examples of biology points made in the response: • Correct use of phototropism

• Correct use of gravitropism (allow geotropism) • Auxin produced in root/shoot

• More hormone/auxin on lower side of root • More hormone/auxin on lower/dark side of shoot • Hormone inhibits growth of root cells

• Hormone stimulates growth of shoot/stem cells • Longer cells on one side

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• Causes root/shoot to bend • Roots grow towards gravity • Shoots grow towards light.

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New AQA GCSE Science © Nelson Thornes Ltd 2011 1 1 a heroin b steroid(s) c statin(s) 1 1 1

2 a To check for unexpected side effects with the higher dose/stronger pain killer.

b To see if the drug cured the headaches.

c A tablet which does not contain a drug/contains a harmless chemical/ a ‘blank’.

d D Neither the doctor nor the patient.

e To rule out psychological effects/description of this.

f To see if the PainGo2/the new drug is better (at curing headaches) than PainGo1. 1 1 1 1 1 1

3 a i tobacco/nicotine/alcohol (accept: solvent/glue/caffeine, ignore cigarettes/coffee)

ii cannabis/heroin/cocaine (allow: crack/weed/ecstasy/LSD/ amphetamine/speed/steroids/ GHB).

b i heroin/cocaine/tobacco/nicotine (ignore: alcohol/cigarettes/ cannabis/caffeine/coffee)

ii alters body chemistry (ignore: withdrawal symptoms/craving/ non-chemical effects on nervous system)

c Any two from:

• increase in cannabis smoking increases (%) depression

• greater effect in women/allow women become more depressed • depression linked with/not directly caused by cannabis/ignore

cannabis causes depression

• not all cannabis smokers get depression.

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4 There is a clear, balanced and detailed argument referring to both pros and cons and a conclusion which matches the pros and cons. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate or relevant specialist terms used accurately.

The answer contains at least one pro and one con with a conclusion. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of specialist terms has been attempted, but not always accurately.

There is mention of either a pro or a con with an attempt at a conclusion or a list of pros and cons without a conclusion, has little clarity and detail. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of understanding of their meaning.

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No relevant content.

Examples of biology points made in the response: Pros, e.g.

• used ‘teenage rats’ as equivalent to human teenagers • THC dose typical of human cannabis smoking habits • used control group

• rats allowed to choose amount of heroin Cons, e.g.

• sample size small/only used 12 rats

• heroin administration very different from human situation Conclusions

• rats given THC/cannabis took more heroin

• (this) is evidence for a link between THC/cannabis and heroin • (but) rat behaviour/ physiology not necessarily same as

human behaviour/ physiology • does not prove link in humans.

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New AQA GCSE Science © Nelson Thornes Ltd 2011 1

1 a i D ii E

b i Any one of: Poor eyesight, legs look awkward for running, no natural predators, other sensible suggestions.

ii Poisonous bite, has poison, strong claws / description

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2 a light

b large seeds with stored food

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3 a i Time of day ii Continuous

b It rises during the night (some time after) 1800 hours to a maximumof 25% at 0900 hours and then falls (more rapidly at first) to a minimum of 5% at 1800 hours

Some accurate reference to actual figures in the table is necessary to obtain the mark.

c Between 2400 hours and 0600 hours. The important words here are

‘more than’. Candidates who ignore these words will include the

figure of 30% and therefore give a response of 2100 hours to 0900 hours.

d The water content of the grasses that it eats are high over this period.

It is night and the gemsboks are therefore less easily seen by predators It is cooler and therefore they are less likely to have to sweat and so this helps them conserve precious water.

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1 a Pyramid drawn with three layers

widest to narrowest either way up but correctly labeled. b Any two from:

• not all the grass eaten is used to make rabbit grow / waste in urea faeces / roots not eaten

• energy is lost due to movement by rabbits /rabbits run around • energy used to keep rabbits warm

• hawks do not eat the whole rabbit

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2 a microorganisms

b moist and warm (either order) c oxygen

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3 a 10 (%)

if wrong answer allow 25+35+30 for 1 mark

b 2.5 if incorrect answer allow 1 mark for correct working. c respiration

d It reduces the calf’s movement because it won’t walk about, therefore it will use that energy for growth. It also reduces the energy the calf will need to use to keep warm and that energy can be used for growth.

reduces movement/walking about reduces energy/transferred by heating/keeps (calf )warm.

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4 There is a clear and detailed description of the sequence of events in the carbon cycle. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used

accurately. The answer shows very few errors in spelling, punctuation and grammar.

There is some description of the sequence of events in the carbon cycle but there is a lack of clarity and detail. The answer has some structure and the use of specialist terms has been attempted, but not always accurately. There may be some errors in spelling, punctuation and grammar.

There is a brief description of the carbon cycle, which has little clarity and detail. The answer is poorly constructed with an absence of specialist terms or their use demonstrates a lack of understanding of their meaning. The spelling,

punctuation and grammar are weak.

No relevant content.

Examples of biology points made in response:

• microorganisms – only allow once if no mention of bacteria or fungi • bacteria

• fungi

• digest / break down organic matter / leaves / decompose / reference decomposers / decay / rot

• respiration

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New AQA GCSE Science © Nelson Thornes Ltd 2011 2

• combustion

• release of carbon dioxide • into the air

• CO2 can be used (by trees) in photosynthesis

• reference to faster in warmer weather / slower during the winter/cold weather.

5 a the sun / light / sunshine / solar

allow radiation from the sun ignore photosynthesis / respiration apply list principle

do not allow water / minerals / heat

b 2.5 (:1)

correct answer with or without working ignore rounding with correct working

do not allow other equivalent ratios for both marks

evidence of selection of 10 (insects) and 4 (frogs) or 50 and 20 or 1 and

0.4 for 1 mark

if no other working allow 1 mark for (1): 0.4 on answer line

c Any two from:

allow for insects or frogs allow energy for biomass

• some parts indigestible / faeces

• waste / examples of waste, e.g. urea / nitrogenous compounds / urine / excretion

• movement / e.g. of movement

allow keeping warm

• heat

• not all eaten / e.g. of not all eaten • respiration

do not accept energy for respiration

d Any four from:

• (bodies) consumed by animals / named / scavengers / detritus feeders • microorganisms / bacteria / fungi / decomposers

• reference to enzymes

• decay / breakdown / decompose / rot ignore digest(ion)

• respiration

• carbon dioxide produced • photosynthesis

• sugar / glucose produced

accept other organic molecules

• fossilisation / fossil fuels / named • combustion / burning

must be linked with fossilisation / fossil fuels

• (burning) produces carbon dioxide

allow carbon dioxide produced once only

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New AQA GCSE Science © Nelson Thornes Ltd 2011 1

Note to teachers – DNA is strictly introduced in Unit BLY2. If candidates give an answer where DNA would be appropriate they will gain credit in BLY1 but it is not essential knowledge.

1 a asexual reproduction b all taste the same

c they are genetically identical

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2 a i kills insects (which eat crop) or increases yield ii Any two from:

• kills insects which may not be pests • poisonous to humans

• expensive

• pollutes the environment

• other relevant suggestions e.g. is not organic iii increases crop yield or reduces cost of pesticide use iv Any one from:

• May lead to increased use of pesticides in the long run / description / ref to last paragraph

• ethical considerations e.g. alters genes of crop

• Do not allow ‘not natural’ ‘against genes may get into wildlife idea, religion’ or similar, not organic.

b There is a clear and detailed scientific description of the sequence of events in genetic engineering. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer shows very few errors in spelling, punctuation and grammar.

There is some description of the sequence of events in genetic

engineering but there is a lack of clarity and detail. The answer has some structure and the use of specialist terms has been attempted, but not always accurately. There may be some errors in spelling, punctuation and grammar.

There is a brief description of the genetic engineering, which has little clarity and detail. The answer is poorly

constructed with an absence of specialist terms or their use demonstrates a lack of understanding of their meaning. The spelling, punctuation and grammar are weak.

No relevant content.

Examples of biology points made in response: • gene from the bacterium

• is cut from the chromosome • using enzymes

• gene transferred to the cotton • (cotton) chromosome – allow cell

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• (the gene) controls characteristics

• causes the cotton (cells) to produce the poison. 3 a Any four from:

• nucleus / DNA / chromosomes / genetic material removed (from egg) • from (unfertilised) egg / ovum linked to second point

allow ‘empty egg cell’ for first two marks do not allow fertilised egg

allow egg from champion cow

• nucleus from body cell of champion (cow) • inserted into egg / ovum

• electric shock

• to make cell divide or develop into embryo

• (embryo) inserted into womb / host / another cow

allow this point if wrong method e.g. embryo splitting

b Any four from: Pros: Max 2 marks

• economic benefit e.g. increased yield / more profit • clone calf not genetically engineered

• genetic material not altered

• milk safe to drink / same as ordinary milk Cons: Max 2 marks

• consumer resistance

• caused by misunderstanding process • not proved that milk is safe

ignore ‘God would not like it’ or ‘it’s not natural’

• ethical / religious argument • reduce gene pool / e.g. Conclusion: Max 1 marks

sensible conclusion for or against, substantiated by information from the passage and / or own knowledge conclusion at end

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New AQA GCSE Science © Nelson Thornes Ltd 2011 1 1 a i Agilisaurus ii Saturnalia iii 7.32 b i billion ii simple c Natural selection 1 1 1 1 1 1

2 Darwin only – Thought that natural selection worked on variations in neck length present at birth.

Lamark only – thought the giraffe stretched its neck while eating leaves in trees. Then its young inherited the longer neck. Both Lamark and Darwin – noticed that the neck of the giraffe changed over time.

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3 Accept any four from:

• mutation (do not accept ‘had to mutate / decided to mutate’) • produces longer snake or there is variation in snake length (do not

accept ‘had to adapt and became longer’)

• longer snake less susceptible to toxin or longer snake survives • survivors reproduce

• gene passed to next generation (allow characteristic passed to next generation)

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References

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