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Long Answer Questions

Q1.Microorganisms cause infections.

The human body has many ways of defending itself against microorganisms.

(a) Describe two ways the body prevents the entry of microorganisms.

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(b) In 2014 the Ebola virus killed almost 8000 people in Africa.

Drug companies have developed a new drug to treat Ebola.

Explain what testing must be done before this new drug can be used to treat people.

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(Total 8 marks)

Q2.There are many ways to increase the efficiency of food production.

(a) The table shows the energy available to humans from two different food chains.

Food chain Energy transferred to humansin kJ per hectare of crop

Wheat → humans 900 000

Wheat → pigs → humans 90 000

(i) Compare the amount of energy the two food chains transfer to humans.

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(ii) Give one reason for the difference in the amount of energy the two food chains transfer to humans.

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(b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Give methods used in the factory farming of animals.Explain the advantages and disadvantages of these methods.

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(Total 8 marks)

Q3.(a) Give three receptors which a mouse might use to detect food under natural

conditions.

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(b) Whilst observing mouse behaviour, a student drops a pen near the mouse’s cage. The mouse jumps at the noise.

Describe, as fully as you can, the processes by which the mouse responds to the stimulus of the dropped pen.

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(Total 9 marks)

Q4.(a) Explain how diseases caused by bacteria are usually treated by doctors.

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(b) Explain, as fully as you can, how white blood cells protect us from disease.

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(Total 7 marks)

Q5.Read the passage.

MMR is a triple vaccine used to protect against three viral diseases. Weakened strains of the three viruses are injected together. The weakened strains cause the body to become immune to the diseases. The vaccine is usually given to children between one and two years old.

Some people believe that the vaccine can trigger a response called autism in children. Autism damages the mental and social development of the child. The vaccine can also lead to problems in the large intestine.

(a) What are the three diseases that the MMR vaccine protects against?

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(b) Use the information in the passage and your own knowledge to evaluate whether a parent should or should not have their child vaccinated.

To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

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(Total 6 marks)

Q6.In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Plants and animals have become adapted in many different ways to reduce the risk of being eaten by predators.

Describe these adaptations.

Give examples of animals and plants adapted in the ways you describe.

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Q7.Mumps is a disease caused by a virus. Mumps vaccine is usually given to children as part of the MMR vaccine.

(a) What diseases, other than mumps, does the MMR vaccine protect against?

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(b) Mumps vaccines contain mumps viruses. Suggest why these viruses do not cause mumps.

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(c) Explain how the vaccine makes someone immune to mumps.

To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

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(d) A child who has not been given the mumps vaccine catches mumps. Suggest why a doctor would not give antibiotics to cure the child of mumps.

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(Total 9 marks)

Q8.The photograph shows a zorse.

By Kumana @ Wild Equines [CC-BY-2.0], via Wikimedia Commons

A zorse is a cross between a male zebra and a female horse.The zorse has characteristics of both parents.

(a) The zorse was produced by sexual reproduction.

(i) What is sexual reproduction?

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(ii) The zorse has characteristics of a zebra and a horse.Why?

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(b) Zorses are not able to breed.Scientists could produce more zorses from this zorse by adult cell cloning.

The diagram shows how the scientists might clone a zorse.

In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Use information from the diagram and your own knowledge to describe how adult cell cloning could be used to clone a zorse.

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(Total 9 marks)

Q9.(a) The graph shows the effect of pH on the activities of three enzymes, X, Y and Z.

These enzymes help to digest food in the human digestive system.Each enzyme is produced by a different part of the digestive system.

pH

(i) What is the optimum (best) pH for the action of enzyme Z?

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(ii) The stomach makes a substance that gives the correct pH for enzyme action in the human stomach.

Name this substance. ____________________________________________(1)

(iii) Which enzyme, X, Y or Z, will work best in the human stomach?

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(b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Different parts of the human digestive system help to break down molecules of fat so that they can be absorbed into the body.

Describe how.

To gain full marks you should refer to:

• the enzyme and where the enzyme is produced

• the products of digestion

• any other chemicals involved.

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(Total 9 marks)


Deforestation affects the environment.

Deforestation is causing a change in the amounts of different gases in the atmosphere. This change causes global warming and climate change.

The image below shows an area of deforestation.

© Nivellen77/iStock/Thinkstock

Give the reasons why deforestation is taking place.

Describe how deforestation is causing the change in the amounts of different gases in the atmosphere.

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Diffusion is an important process in animals and plants.

The movement of many substances into and out of cells occurs by diffusion.

Describe why diffusion is important to animals and plants.

In your answer you should refer to:

• animals

• plants

• examples of the diffusion of named substances.

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Animals and plants have features (adaptations) that allow them to survive in the conditions in which they normally live.

Describe how animals and plants are adapted to survive in dry conditions such as deserts.

For each adaptation that you give, describe how the adaptation helps the animal or plant to survive in dry conditions.

To obtain full marks you should refer to both animals and plants.

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The human body is kept at a constant internal temperature of about 37 °C.

Body temperature is monitored and controlled by the thermoregulatory centre in the brain.

Describe what happens in the body to keep the body temperature constant.

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Q14.The circulatory system transports substances such as glucose and oxygen around the body.

(a) Name two other substances that the circulatory system transports around the body.

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(b) (i) Blood is a tissue. Blood contains red blood cells and white blood cells.

Name two other components of blood.

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2. ____________________________________________________________(2)

(ii) The heart is part of the circulatory system.

What type of tissue is the wall of the heart made of?

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(c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Every year, many patients need to have heart valve replacements.

The table gives information about two types of heart valve.

Living human heart valve Cow tissue heart valve

• It has been used for transplants for more than 12 years. • It has been used since 2011.

• It can take many years to find a suitable human donor.

• It is made from the artery tissue of a cow.

• It is transplanted during an operation after a donor has been found.

• It is attached to a stent and inserted inside the existing faulty valve.

• During the operation, the patient's chest is opened and the old valve is removed before the new valve is transplanted.

• A doctor inserts the stent into a blood vessel in the leg and pushes it through the blood vessel to the heart.

A patient needs a heart valve replacement. A doctor recommends the use of a cow tissue heart valve.

Give the advantages and disadvantages of using a cow tissue heart valve compared with using a living human heart valve.

Use information from the table and your own knowledge in your answer.

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(Total 11 marks)

Q15.The parts of the blood can be separated from each other by spinning the blood in a centrifuge.

The image below shows the separated parts of a 10 cm3 blood sample.

(a) Calculate the percentage of the blood that is made up of plasma.

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Answer = _______________ %(2)

(b) Name three chemical substances transported by the plasma.

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(c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

White blood cells are part of the immune system. White blood cells help the body to defend itself against pathogens.

Describe how pathogens cause infections and describe how the immune system defends the body against these pathogens.

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(Total 11 marks)


Plants transport many substances between their leaves and roots.

The diagram below shows the direction of movement of substances through a plant.

Describe how ions, water and sugar are obtained and transported through plants.

In your answer you should refer to materials moving upwards in a plant and to materials moving downwards in a plant.

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Q17.A gardener wants to add compost to the soil to increase his yield of strawberries.

The gardener wants to make his own compost.

(a) An airtight compost heap causes anaerobic decay.

Explain why the gardener might be against producing compost using this method.

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(b) The gardener finds this research on the Internet:

‘A carbon to nitrogen ratio of 25:1 will produce fertile compost.’

Look at the table below.

Type of material to compost

Mass of carbon in

sample in g

Mass of nitrogen

in sample in gCarbon:nitrogen ratio

Chicken manure 8.75 1.25 7:1

Horse manure 10.00 0.50 20:1

Peat moss 9.80 0.20 X

Determine the ratio X in the table above.

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(c) Which type of material in the table above would be best for the gardener to use to make his compost?

Justify your answer.

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(d) Some of the leaves from the gardener’s strawberry plant die.

The dead leaves fall off the strawberry plant onto the ground.

The carbon in the dead leaves is recycled through the carbon cycle.

Explain how the carbon is recycled into the growth of new leaves.

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(e) The diagram below shows two strawberries.

• Both strawberries were picked from the same strawberry plant.

• Both strawberries were picked 3 days ago.

• The strawberries were stored in different conditions.

Strawberry A Strawberry B

Give three possible reasons that may have caused strawberry A to decay.

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(Total 13 marks)

Q18.Many different types of animals are produced using selective breeding.

Some cats are selectively bred so that they do not cause allergies in people.

(a) Suggest two other reasons why people might selectively breed cats.

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(b) Selective breeding could cause problems of inbreeding in cats.

Describe one problem inbreeding causes.

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(c) Many people have breathing problems because they are allergic to cats.

The allergy is caused by a chemical called Fel D1.

Different cats produce different amounts of Fel D1.

A cat has been bred so that it does not produce Fel D1.

The cat does not cause an allergic reaction.

Explain how the cat has been produced using selective breeding.

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(Total 7 marks)

Mark schemes

Q1.(a) any two from:

• acid in the stomach kills pathogens in food• skin forms a barrier / produces antimicrobial secretions• hairs in the nose trap (particles which may contain) pathogens• trachea / bronchi has mucus which traps pathogens or bronchi have cilia which waft mucus to throat to be swallowed

2

(b) Level 3 (5–6 marks):A clear, logical and coherent answer, with no significant redundancy. The student understands the process and links this to reasons for clinical trials.

Level 2 (3–4 marks):A partial answer with errors and ineffective reasoning or linkage.

Level 1 (1–2 marks):One or two relevant points but little linkage of points or logical reasoning.

0 marks:No relevant content.

Indicative content• pre-clinical trials of the new drug on cells / tissues / live animals• to test toxicity, dosage and efficacy• clinical trials / test on healthy volunteers and Ebola patients at very low doses• so that you can monitor for safety / side effects• and only then do trials to find the optimum dosage and test for efficacy• double blind trial / use of placebo• which does not contain the new drug• random allocation of Ebola patients to groups• so no one knows who has placebo / the new drug• peer review of data• to help prevent false claims

6[8]

Q2.(a) (i) wheat → humans chain transfers 10 times more energy than wheat → pigs →

humans chainallow 10% if given as a comparison e.g. one is 10% of the other

or

wheat → pigs → humans chain transfers 810 000 (kJ per hectare) lessignore less unqualified

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(ii) any one reason for energy loss from pigs e.g :ignore respiration, growthignore heat unqualified

• movement

• (maintaining) body temperature

• waste materialsallow named examples

• not all parts of pig eaten by human

• because there is an extra stage (pigs) in the food chain and energy is lost at each stageallow longer food chain so more energy lost

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(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. Examiners should also refer to the information in the Marking guidance, and apply a ‘best-fit’ approach to the marking.

0 marksNo relevant content.

Level 1 (1-2 marks)There is a basic description of at least one factory farming method oridentification of an advantage or disadvantage of factory farming.

Level 2 (3-4 marks)There is a description of at least one factory farming method andan advantage or disadvantage is explained.

Level 3 (5-6 marks)There is a description of factory farming methods andadvantage(s) and disadvantage(s) are explained.

Examples of Biology points made in the response:

factory farming methods e.g.:

• Kept in cramped conditions / battery hens / calf crates / pig barns / fish tanks

• Controlled temperature / heating

• Controlled feeding / modified food given / growth hormones

• Controlled lighting

• Treated with prophylactic antibiotics

Advantages e.g.:

• Increased efficiency / profit / greater food production / cheaper food / faster growth

• Farmer can have more livestock

• Less energy is lost through movement

• Less energy is used keeping warm

• (Food is high in calories / protein) so animals will grow faster / lay more eggs

• Easier to vaccinate all the animals

• Easier to protect animals from predators

• Antibiotic treatment stops infections in animals

Disadvantages e.g.:

• Stress / cruelty / inhumane / unethical

• Restricted movement / overcrowding

• Faster spread of diseases

• Antibiotics in the food chain / residual chemicals in the food chain

• Wasting fossil fuels / increasing global warming

• Increased pollution from animal waste and from additional transport6

[8]

Q3.(a) light/eye

smell/nosetaste/chemical/tongue

for 1 mark each3

(b) 6 of e.g.receptors in ear detect sound waves/vibrationsimpulses/electrical signals to brainbrain co-ordinates responseimpulses sent along nervesto muscles/effectors which contract to bring about response

any 6 for 1 mark each6

[9]

Q4.(a) use antibiotics; or named one to kill bacteria; (not microbes)

each for 1 mark2

(b) some ingest/digest bacteria (not microbes) OWTTEsome produce antibodies;which destroy bacteria/viruses;some produce antitoxins;which counteract poisons released by bacteria

each for 1 mark5

[7]

Q5.(a) measles mumps rubella / German measles

any order1

(b) Quality of written communication:for giving at least two statements linked to vaccination

1

any four from:NB max 3 marks for only one side of argumentdo not accept economic argument

a valid reference to paineg pain of vaccination / disease

should

protect against diseases

measles / mumps / rubella are dangerous diseases / can cause lasting harm / death

cannot be treated by antibiotics

problem of epidemics

should not

may suffer autism / damage to mental / social development

may suffer large intestine disorders

separate vaccines available that cause no / less problems4

[6]

Q6.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a 'best-fit' approach to the marking.

0 marks

No relevant content.

Level 1 (1-2 marks)There is at least one example of an adaptation of either an animal or a plant. However it may not be clear how the adaptation helps the organism to avoid being eaten.

Level 2 (3-4 marks)There is a description of an adaptation of at least one animal and at least one plant. It is clear how at least one of these adaptations helps the organism to avoid being eaten.

Level 3 (5-6 marks)There are clear and detailed descriptions of a range of adaptations of named animals and named plants. It is clear how most of these adaptations help the organisms to avoid being eaten.

examples of clear and detailed biology points made in response:

• camouflage – the method of camouflage should be described plus a statement that the predator is less likely to see the prey

• mimicry / warning colouration – the method should be described plus a statement that the predator is likely to confuse the prey with e.g. a poisonous organism

• thorns / prickles / spines / horns – a statement that these are sharp and are likely to hurt a predator

• long limbs / streamlining – a statement that these increase speed and make it more likely that prey will outrun predator

• bad taste / poison – a statement that predator will find this unpleasant and ‘spit out’ prey / not attack same prey again

• large ears / position of eyes – a statement that predators will be detected earlier so the prey can escape sooner

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Q7.(a) measles

ignore mumps1

rubellaaccept German measles

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(b) viruses are ‘dead’accept other viral treatmentsaccept ‘non-virulent’mild’ must be qualifieddo not accept ‘small dose’

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(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 proteinsaccept reference to immunologicalmemory or memory cells’

white cells (accept lymphocytes)do not accept phagocytes

idea of specificity in antibodies or antigens

antibody productionignore engulfing

antigens destroyed / virus destroyed

rapid antibody production if infectedmax 5

(d) antibiotics do not kill / affect viruses1

[9]

Q8.(a) (i) fusion / joining / combining of gametes / egg and sperm / sex cells

accept fertilisationallow fusion / joining / combining DNA from two parentsignore meeting / coming together / mixing of gametes etc

1

(ii) (mixture of) genes / DNA / genetic information / chromosomesignore nucleus / inherited information but allow second mark if given

1

from both parents / horse and zebradependent on sensible attempt at 1st mark

1

(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. Examiners should apply a 'best-fit' approach to the marking.

0 marksNo relevant content

Level 1 (1-2 marks)There is simple description of the early stages of adult cell cloning. However there is little other detail and the description may be confused or inaccurate.

Level 2 (3-4 marks)There is an almost complete description of the early stages of the process and description of some aspects of the later stages. The description may show some confusion or inaccuracies.

Level 3 (5-6 marks)There is a clear, detailed and accurate description of all the major points of how adult cell cloning is carried out.

Examples of Biology points made in the response could include:

• skin cell from zorse

• (unfertilised) egg cell from horse

• remove nucleus from egg cell

• take nucleus from skin cell

• put into (empty) egg cell

• (then give) electric shock

• (causes) egg cell divides / embryo formed

• (then) place (embryo) in womb / uterus6

[9]

Q9.(a) (i) 8.6

accept value in range 8.5 to 8.71

(ii) hydrochloric acid / HClaccept HCLaccept hydrogen chlorideignore hcl / etc.

1

(iii) X1

(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. Examiners should also refer to the information in the Marking guidance.


Level 1 (1-2 marks)There is a simple description of part of a process or a reference to at least one of: mechanical digestion, lipase, product of enzyme action, bile, site of production or site of digestion

Level 2 (3-4 marks)There is a description of at least one process linking ideas

Level 3 (5-6 marks)There is a clear description of the process including reference to the majority of: mechanical digestion, lipase, bile, where they are produced, products, function of bile and site of digestion / absorption

Examples of biological points made in the response:

• mechanical breakdown in mouth / stomach

• fats →fatty acids and / or glycerol

• by lipase

• (produced by) pancreas

• and small intestine

• fat digestion occurs in small intestine

• bile

• produced by liver

• neutralises acid from stomach

• produces alkaline conditions in intestine

• refs. to increased surface area related to emulsification or chewing

• products are small molecules / water-soluble

• products absorbed by small intestine6

[9]

Q10.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a ‘best-fit’ approach to the marking.


Level 1 (1 – 2 marks)There is at least one reason for deforestationoran attempt at a description of at least one way deforestation is affecting the atmosphere.

Level 2 (3 – 4 marks)There is at least one reason for deforestationanda description of the way deforestation is affecting one gas in the atmosphereorthe process that causes an effect.

Level 3 (5 – 6 marks)There are reasons for deforestationanda clear description of the way deforestation is affecting one gas in the atmosphereandthe process that causes this.

examples of the points made in the response

Reasons for deforestation

• timber for construction / furniture / boat building / paper production• growing plants for biofuels for motor fuel / aviation / lawnmowers• use of wood as a fuel• land for building or agriculture to provide food, such as rice fields and cattle

ranching

Effects of deforestation

• increase in carbon dioxide in atmospheredue to burningdue to activities of microbesless carbon dioxide taken in / locked up (by trees)less photosynthesis

• increase in methane in atmospheredue to rice production / cattle

extra information

ignore references to oxygenaccept explanations of the effect of water (vapour)

[6]

Q11.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a ‘best-fit’ approach to the marking.


Level 1 (1 – 2 marks)An example is given of a named substanceora processorthere is an idea of why diffusion is important eg definition.

Level 2 (3 – 4 marks)At least one example of a substance is givenandcorrectly linked to a process in either animals or plants.

Level 3 (5 – 6 marks)There is a description of a process occurring in either animals or plants that is correctly linked to a substanceanda process occurring in the other type of organism that is correctly linked to a substance.

examples of points made in the response

Importance of diffusion:

• to take in substances for use in cell processes• products from cell processes removed

Examples of processes and substances:

• for gas exchange / respiration: O2 in / CO2 out• for gas exchange / photosynthesis: CO2 in / O2 out• food molecules absorbed: glucose, amino acids, etc• water absorption in the large intestine• water lost from leaves / transpiration• water absorption by roots• mineral ions absorbed by roots

extra informationDescription of processes might include:• movement of particles / molecules / ions• through a partially permeable membrane• (movement of substance) down a concentration

gradient• osmosis: turgor / support / stomatal movements

[6]

Q12.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should apply a ‘best-fit’ approach to the marking.


Level 1 (1 – 2 marks)At least one way in which animals and / or plants are adapted to survive.

Level 2 (3 – 4 marks)A description of ways in which animals and / or plants are adapted and an attempt to link at least one adaptation to how it increases the chance of survival.

Level 3 (5 – 6 marks)A description of ways in which animals and plants are adapted and a description of how at least one adaptation increases the chance of survival.

examples of biology points made in the response:

(animals)

(A) change / decrease in surface area / example(decrease in surface area which) reduces area from which sweat / water may be lost

(A) hump with fat / fat stores(fat in hump) to convert to water (via respiration)

(A) long eyelashes(long eyelashes) to keep (wind-blown) dust out of eyes

(A) nocturnal / ‘keep out of the sun’reduce sweat loss (in heat of the day)

extra informationallow adaptations of specific animals to living in specified dry conditions, eg a desert

(A) change / increase in surface area / example(increase in surface area which) increases area heat may be lost from (by radiation)

(A) changes to thickness of insulating coat(thicker coat on upper surface) increases insulation from sun’s heat

(A) thin (layer) / reduced amount of body fat(reduced amount of body fat which) reduces insulating layer

(A) wide feet(wide feet) to reduce pressure / spread weight / prevent sinking

(plants)

(A) decrease in surface area

(A) leaves are spikes(reduced area / leaves are spikes) reduces water loss / transpiration / evaporation

(A) long / wide spread / extensive roots(long / wide spread /extensive roots) to absorb (more) water

(A) fleshy / thick stem(fleshy / thick stem) to store water

extra information

allow adaptations of specific plants to living in specified dry conditions, eg a desert

(A) thick wax(thick wax) to reduce evaporation / water loss / transpiration

(A) few(er) stomata(few stomata) to reduce evaporation / water loss / transpiration

[6]

Q13.Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also apply a ‘best-fit’ approach to the marking.


Level 1 (1 – 2 marks)There is a description of thermoregulation or at least one correct mechanism (skin, sweat glands or muscles) but roles may be confused.

Level 2 (3 – 4 marks)There is a description of thermoregulation or some correct mechanisms (sweating, shivering, blood flow in the skin).

Level 3 (5 – 6 marks)There is a clear description of thermoregulation by TC or skin and some correct control mechanisms.

examples of biology points made in the response:full marks may be awarded for detailed description of what happens if the core temperature is either too high or too low

• temperature receptors in TC• the TC detects (core) body / blood temperature• temperature receptors in the skin send impulses to the TC, giving information

about skin temperature• if the core body temperature is too high: blood vessels / arterioles supplying

the skin capillaries dilate / vasodilationdo not accept refs to veins instead of arterioles or answers that imply blood vessels have moved up / down through the skin.

• so that more blood flows (through the skin) and more heat is lost• sweat glands release more sweat to cool the body• by evaporation

• if the core body temperature is too low: blood vessels supplying the skin capillaries constrict

• to reduce the flow of blood (through the skin) and less heat is lostallow idea of blood diverted to vital organs in extreme cold

• muscles may shiver to release (heat) energy• from respiration, some of which is lost as heat

[6]


• carbon dioxide / CO2

• urea• protein• water / H2O• hormones / insulin.

ignore food / waste / alcohol / drugs / enzymesignore glucose and oxygenallow two correct hormones for 2 marksallow two correct food components for 2 marksallow antibodiesallow antitoxins

2

(b) (i) plasma1

platelets1

(ii) (cardiac) muscleallow muscular

1

(c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also refer to the information in the Marking Guidance and apply a ‘best-fit’ approach to the marking.


Level 1 (1−2 marks)There is a description of at least one advantage of the cow tissue valveora description of at least one disadvantage of the cow tissue valve.

Level 2 (3−4 marks)There is a description of at least one advantage of the cow tissue valveandat least one disadvantage of the cow tissue valve.

Level 3 (5−6 marks)There is a description of the advantages and disadvantages of the cow tissue valveora description of several advantages of the cow tissue valve and at least one disadvantage.

Examples of the points made in the response

Advantages of cow tissue valve:

• abundant supply of cows• so shorter waiting time

ignore can take many years to find a suitable human donor• no need for tissue typing• quicker operation• less invasive or shorter recovery time• cheaper operation costs• less operation / anaesthetic risks.

Disadvantages of cow tissue valve:

• made from cow so possible objections on religious groundsignore ethical arguments

• new procedure so could be unknown risksallow possible transfer of disease from cow

• risks of using a stent eg. blood clots, stent breaking or valve tearing

• not proven as a long term treatment• may be rejected

ignore information copied directly from the table without value added.

6[11]

Q15.(a) 55%

2 marks for correct answer aloneaccept 54 − 565.5 / 10 × 100 alone gains 1 mark

2

(b) any three from:

• amino acids• antibodies• antitoxins• carbon dioxide• cholesterol• enzymes• fatty acid• glucose• glycerol• hormones / named hormones• ions / named ions• proteins• urea• vitamins• water.

ignore blood cells and plateletsignore oxygenmax 1 named example of each for ions and hormonesallow minerals

3

(c) Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information in the Marking Guidance and apply a ‘best-fit’ approach to the marking.


Level 1 (1 – 2 marks)There is a description of pathogens with errors or roles confused.orthe immune response with errors or roles confused.

Level 2 (3 – 4 marks)There is a description of pathogens and the immune response with some errors or confusionora clear description of either pathogens or the immune response with few errors or little confusion.

Level 3 (5 – 6 marks)There is a good description of pathogens and the immune response with very few errors or omissions.

Examples of biology points made in the response:

• bacteria and viruses are pathogenscredit any ref to bacteria and viruses

• they reproduce rapidly inside the body• bacteria may produce poisons / toxins (that make us feel ill)• viruses live (and reproduce) inside cells (causing damage).

white blood cells help to defend against pathogens by:

• ingesting pathogens / bacteria / (cells containing) virusescredit engulf / digest / phagocytosis

• to destroy (particular) pathogen / bacteria / viruses• producing antibodies• to destroy particular / specific pathogens• producing antitoxins• to counteract toxins (released by pathogens)

credit memory cells / correct description• this leads to immunity from that pathogen.

6[11]

Q16.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.

Level 3 (5–6 marks):Processes used for obtaining specified materials are given.andcorrectly linked to the vessels that the materials are transported inorcorrectly linked to a description of the direction of movement of the materials.

For full credit, in addition to the above descriptors at least one of the processes must be linked to the vessel that the material is transported in and the direction of the movement of the material.

Level 2 (3–4 marks):At least one process for obtaining a specified material is givenandis correctly linked to the vessel that the material is transported inorcorrectly linked to a description of the direction of movement of the material

Level 1 (1–2 marks):At least one process (P) for obtaining a material is givenorat least one vessel (V) and the material it carries is givenorthere is a description of the direction of movement (M) for at least one material

0 marks:No relevant points are made

examples of points made in the response Ions:(P) taken up by diffusion or active transport• from an area of high to low concentration (diffusion) or an area of low to high

concentration (active transport)(V) travels in the xylem(M) to the leaves or from the roots / soil

Water:(P) taken up by osmosis• from an area of low to high concentration

allow high concentration of water to low concentration of waterallow from high water potential to low water potentialignore along a concentration gradient

(V) travels in the xylem(M) to the leaves or from the roots / soil(P) transpiration stream

• movement replaces water as it evaporates from leaves(V) in the xylem

Sugar:(P) made during photosynthesis(V) travels in the phloem(M) to other parts of the plant or to storage organs or travels up and down

[6]

Q17.(a) methane is produced

ignore bad smell1

which is a greenhouse gas / causes global warming1

(b) (9.80 / 0.20 = 49 therefore) 49:11

(c) horse (manure)allow ecf from 11.2

closest to 25:1 (ratio)1

(d) Level 3 (5–6 marks):A detailed and coherent explanation is given, which logically links how carbon is released from dead leaves and how carbon is taken up by a plant then used in growth.

Level 2 (3–4 marks):A description of how carbon is released from dead leaves and how carbon is taken upby a plant, with attempts at relevant explanation, but linking is not clear.

Level 1 (1–2 marks):Simple statements are made, but no attempt to link to explanations.


Indicative content

statements:• (carbon compounds in) dead leaves are broken down by microorganisms /

decomposers / bacteria / fungi• photosynthesis uses carbon dioxide

explanations:• (microorganisms) respire• (and) release the carbon from the leaves as carbon dioxide• plants take in the carbon dioxide released to use in photosynthesis to produce

glucose

use of carbon in growth:• glucose produced in photosynthesis is used to make amino acids / proteins /

cellulose• (which are) required for the growth of new leaves

6

(e) any three from:(storage conditions)• (at) higher temperature / hotter• (had) more oxygen• (had) more water / moisture• (contained) more microorganisms (that cause decay)

allow reference to bacteria / fungi / mould3

[13]


• so that they do not have specific genetic defects• to produce docile cats or so they are not aggressive

allow descriptions of aggression such as biting and scratching

• for aesthetic reasons

allow descriptions of suitable aesthetic reasons2

(b) (cats) are more likely to pass on (recessive) disordersormore likely to be susceptible to diseases

1

(c) Level 2 (3–4 marks):A detailed and coherent explanation is given, which logically links the process of selective breeding with explanations of how this produces cats that do not cause allergic reactions.

Level 1 (1–2 marks):Simple statements are made relating to process of selective breeding, but no attempt tolink to explanations.


Indicative content

process:• parents with the desired characteristic are selected• the parents are bred together to produce offspring• offspring with the desired characteristics are selected and bred• this is repeated over many generations.

explanations:• parents who produce the least Fel D1 are initially selected• in their offspring there will be individuals with differing amounts of Fel D1

produced• care is taken to ensure cats are healthy and avoid possible problems

associatedwith selective breeding

• over time the population of (selectively bred) cats will produce less Fel D14

[7]

sciencerevisionoalp.files.wordpress.com · Web viewThe answer to this question requires good English in a sensible order with correct use of scientific terms. Quality of written

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