mis web view(ii) which word describes a whole leaf? draw a ring around . one. answer ... m16. x...

Q1.Villi are found in some parts of the digestive system.

Diagram 1 shows two villi.

Diagram 1

(a) Draw a ring around the correct answer to complete each sentence.

muscle.

(i) Structure A is a nerve.

capillary.

(1)

dialysis.

(ii) The villi absorb the products of digestion by diffusion.

osmosis.

(1)

(b) Diagram 2 shows the digestive system.

Diagram 2

(i) In which part of the digestive system, X, Y or Z, are most villi found? (1)

(ii) There are about 2000 villi in each cm2 of this part of the digestive system.

Why is it helpful to have lots of villi?

...............................................................................................................

...............................................................................................................(1)

(Total 4 marks)

Q2. Diagrams A, B and C show cells from different parts of the human body, all drawn to the same scale.

(a) Which cell, A, B or C, appears to have adaptations to increase diffusion into or out of the cell?

Give one reason for your choice.

........................................................................................................................

........................................................................................................................(1)

(b) (i) Cell C is found in the pancreas.

Name one useful substance produced by the pancreas.

...............................................................................................................(1)

(ii) Use information from the diagram to explain how cell C is adapted for producing this substance.

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............................................................................................................... (2) (Total 4 marks)

Q3. Red squirrels live in trees. They eat seeds from the cones of conifer trees. Squirrels store cones in ‘larders’ on the ground. These larders provide food through the winter. Each red squirrel makes and defends one larder.

Scientists monitor squirrel numbers to find the best habitats for the squirrel’s survival. In one investigation, scientists estimated the numbers of squirrels in different types of woodland. Each woodland contains a different species of conifer tree.

Here is their method.

• Ten woods of each type of woodland were surveyed.

• In each wood scientists measured out two transects (strips), each 600 m long and 10 m wide.

• A scientist walked slowly down the centre of each transect, recording the number of squirrel larders he could see.

(a) Name one variable that was controlled in this investigation.

........................................................................................................................(1)

(b) (i) The scientists recorded the number of larders instead of the number of squirrels they saw.

How could this have increased the accuracy of the investigation?

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...............................................................................................................(1)

(ii) This method of counting the number of larders could have led to an inaccurate estimate of the number of squirrels.

Explain how.

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(2)

(c) The results of the investigation are shown on the graph.

Each bar represents the range of the number of larders in each type of woodland.

The horizontal mark on each bar represents the mean number of larders per hectare of woodland.

(c) A student concluded ‘You will always find more squirrels in spruce woodland than in fir woodland.’

Is the student’s conclusion justified by the data in the graph?

Explain the reasons for your answer.

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(Total 6 marks)

Q4. (a) Photosynthesis is a process that takes place in green plants.

(i) What type of energy is needed for this process?

..........................................................................................................................(1)

(ii) What substance in the plant absorbs this energy?

..........................................................................................................................(1)

(iii) In which part of the plant cell does photosynthesis take place?

..........................................................................................................................(1)

(iv) Write a balanced chemical equation for photosynthesis.

......................................................... → ..........................................................(3)

(b) Describe two ways you could speed up photosynthesis.

.....................................................................................................................................

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................................................................................................................................. (2)

(c) The diagram shows the outline of a cross-section of a leaf. Name cells 1 and 2 and describe how they are involved in photosynthesis.

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(4)(Total 12 marks)

Q5. Leaves are made from layers of cells.

The diagram shows a section through part of a leaf.

(a) (i) Which word in the table describes layer A? Tick ( ) one box.

Layer A Tick( )

Tissue

Organ

Cell

(1)

(ii) Which word describes a whole leaf? Draw a ring around one answer.

organ tissue organism(1)

(b) (i) Which two layers of cells, A, B, C and D, can photosynthesise?

Use information from the diagram to help you. Tick ( ) two boxes.

Layer A

Layer B

Layer C

Layer D

(2)

(ii) Give one reason for your answer.

...............................................................................................................(1)

(c) List X gives the names of two parts of a cell.List Y gives information about parts of a cell.Draw one line between each part of the cell in list X and information about it in list Y.

List XPart of a cell

List YInformation

Controls the passage ofsubstances into the cell

Vacuole

Contains the cell sap

Nucleus

Controls the activities of thewhole cell

(2)(Total 7 marks)

Q6. The graph shows the mean light intensity at different times of the year in an oak wood.

(a) (i) In which month would you expect the rate of photosynthesis in the oak trees to be greatest?

.........................................................................(1)

(ii) There are plants living on the ground in the wood. In which month would you expect their rate of growth to be fastest?

...........................................................................................................................

Explain your answer.

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...........................................................................................................................(3)

(b) Name two factors, other than light intensity, that would affect the rate of photosynthesis in the oak trees.

1 ..................................................................................................................................

2 ..................................................................................................................................(2)

(Total 6 marks)

Q7. Read the following information about how the small intestine absorbs sugars.

• The blood absorbs glucose and some other sugars, like xylose, from the small intestine.

• Glucose molecules are the same size as xylose molecules, but glucose is absorbed more quickly than xylose.

• Experiments with pieces of intestine show that the uptake of oxygen by the intestine is 50 % higher in the presence of glucose than in the absence of glucose. Xylose does not have this effect on the uptake of oxygen.

• The cells lining the small intestine have many mitochondria.

Explain how this information provides evidence that glucose is absorbed by the small intestine using active transport.

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(Total 4 marks)

Q8. Some students set up the equipment below to investigate osmosis.

(a) What is osmosis?

....................................................................................................................................

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....................................................................................................................................(3)

(b) (i) What will happen to the water level in the capillary tube during the investigation because of osmosis?

...........................................................................................................................(1)

(ii) Use your knowledge of osmosis to explain why this happens.

...........................................................................................................................(2)

(Total 6 marks)

Q9.White blood cells protect the body against pathogens such as bacteria and viruses.

(a) (i) Pathogens make us feel ill.

Give one reason why.

...............................................................................................................

...............................................................................................................(1)

(ii) White blood cells produce antibodies. This is one way white blood cells protect us against pathogens.Give two other ways that white blood cells protect us against pathogens.

1.............................................................................................................

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2.............................................................................................................

...............................................................................................................(2)

(b) Vaccination can protect us from the diseases pathogens cause.

(i) One type of virus causes measles. A doctor vaccinates a child against measles.What does the doctor inject into the child to make the child immune to measles?

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...............................................................................................................(2)

(ii) A few weeks after the vaccination, the child becomes infected with measles viruses from another person.

The graph shows the number of measles antibodies in the child’s blood from before the vaccination until after the infection.

More measles antibodies are produced after the infection than after the vaccination.

Describe other differences in antibody production after infection compared with after vaccination.

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(iii) Vaccination against the measles virus will not protect the child against the rubella virus.

Why?

...............................................................................................................(1)

(c) What is the advantage of vaccinating a large proportion of the population against measles?

........................................................................................................................(1)

(Total 10 marks)

Q10. There is a large amount of evidence that evolution is taking place.

(a) Scientists are uncertain about how life started on Earth.

Explain why.

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........................................................................................................................(2)

(b) Salamanders are terrestrial amphibians. The diagram shows the distribution of four different species of salamander in a country.

Originally, there was only one species of salamander in the country.

Suggest an explanation for the development of the four different species.

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(Total 7 marks)

Q11. The diagram shows the evolution of a group called the primates.

(a) Which primate evolved first?

........................................................................................................................(1)

(b) Name two primates that developed most recently from the same common ancestor as humans.

1 .....................................................................................................................

2 .....................................................................................................................(2)

(c) (i) The theory of evolution by natural selection was suggested in the 1800s.

Which scientist suggested this theory?

...............................................................................................................(1)

(ii) Use words from the box to complete the passage about natural selection.

evolution environment generation

mutate survive variation

Individual organisms of a species may show a wide range of

............................................................. because of differences in their genes.

Individuals with characteristics most suited to the ...................................

are more likely to ............................................................. and breed successfully.

The genes that have helped these individuals to survive are then passed on to the

next ..............................................................(4)

(Total 8 marks)

Q12.The photograph shows a fossil of a prehistoric bird called Archaeopteryx.

(a) Describe three ways fossils can be made.

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........................................................................................................................ (3)

(b) The drawing shows what an Archaeopteryx might have looked like when it was alive.

Scientists think that Archaeopteryx was a predator.

(i) Look at the drawing.

Write down three adaptations that might have helped Archaeopteryx to catch prey.

How would each adaptation have helped Archaeopteryx to catch prey?

Adaptation 1 ..........................................................................................

How it helps ..........................................................................................

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Adaptation 2 ..........................................................................................

How it helps ..........................................................................................

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Adaptation 3 ..........................................................................................

How it helps ..........................................................................................

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(ii) Archaeopteryx is now extinct.

Give two reasons why animals may become extinct.

1 .............................................................................................................

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2 .............................................................................................................

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(Total 8 marks)

Q13. MRSA strains of bacteria are causing problems in many hospitals.

(a) The diagram shows a hand-gel dispenser.

Hand-gel dispensers are now placed at the entrance of most hospital wards. Explain why.

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........................................................................................................................ (2)

(b) Explain, as fully as you can, how MRSA strains of bacteria became difficult to treat.

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(Total 5 marks)

Q14. The dodo is an extinct bird. The drawing shows an artist’s impression of the bird.

The dodo lived on a small island in the middle of the Indian Ocean. Its ancestors were pigeon-like birds which flew to the island millions of years ago. There were no predators on the island. There was a lot of fruit on the ground. This fruit became the main diet of the birds. Gradually, the birds became much heavier, lost their ability to fly and evolved into the dodo.

(a) Suggest an explanation for the evolution of the pigeon-like ancestor into the flightless dodo.

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(4)

(b) The dodo became extinct about 80 years after Dutch sailors first discovered the island in the eighteenth century.

Scientists are uncertain about the reasons for the dodo’s extinction.

Suggest an explanation for this uncertainty.

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.....................................................................................................................................(1)

(Total 5 marks)

Q15. (a) List A gives four structures in the human body.

List B gives the functions of some structures in the body.

Draw a straight line from each structure in List A to the correct function in List B.

List A – Structure List B – Function

Surround and protect the lungs

Alveoli

Filter the blood

Veins

Carry blood towards the heart

Villi

Absorb digested food

Ribs

Allow oxygen to enter the blood

(4)

(b) Draw a ring around the correct answer to complete the sentence.

diffusion.

In the lungs, oxygen enters the blood from the air by filtration.

respiration.

(1)

(Total 5 marks)

Q16. The diagram shows an enlargement of structure D.

The arrows show the direction of the gases exchanged in this structure. Name gas X and gas Y.

X ...........................................................................................................................................

Y ...........................................................................................................................................(Total 2 marks)

Q17.Gas exchange takes place in the lungs.

The diagram shows an alveolus next to a blood capillary in a lung.

The arrows show the movement of two gases, A and B.

(a) (i) Draw a ring around the correct answer to complete the sentence.

Gases A and B move by

diffusion.

osmosis.

respiration.

(1)(ii) Gas A moves from the blood to the air in the lungs. Gas A is then breathed out.

Name Gas A.

............................................................................................................... (1)(iii) Which cells in the blood carry Gas B?

Draw a ring around the correct answer.

platelets red blood cells white blood cells(1)

(b) The average number of alveoli in each human lung is 280 million.

The average surface area of 1 million alveoli is 0.25 m2.

Calculate the total surface area of a human lung.

........................................................................................................................

Answer ...................................................................... m2

(2)

(c) An athlete trains to run a marathon. The surface area of each of the athlete’s lungs has increased to 80 m2.

Give one way in which this increase will help the athlete.

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........................................................................................................................(1)

(Total 6 marks)

(a) The table shows the effect of exercise on the action of one person’s heart.

At rest Duringexercise

Heart rate in beats per minute 72 165

Volume of blood leaving the heart in each beatin cm3

75 120

Heart output in cm3 per minute 5400

(i) Calculate the heart output for this person during exercise. Show clearly how you work out your answer.

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Answer = .............................. cm3 per minute(2)

(ii) During exercise, more oxygen is carried to the working muscles.

Explain why this is helpful during exercise.

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(b) Give two other changes in the body that help to increase the amount of oxygen delivered to the working muscles during exercise.

1 ..................................................................................................................................

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2 ..................................................................................................................................

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(Total 6 marks)

Q19.Diagram 1 shows a section through the heart.

Diagram 1

(a) Use words from the box to name the structures labelled A and B on Diagram 1.

arota atrium pulmonary artery ventricle

A ......................................................................................................................

B ......................................................................................................................

(2)

(b) The tissue in the wall of the heart contracts. (i) What type of tissue is this?

Tick ( ) one box.

muscular

glandular

epithelial

(1)

(ii) What does the heart do when this tissue contracts?

...............................................................................................................

...............................................................................................................(1)

(c) Draw arrows on Diagram 2 to complete the route taken by deoxygenated blood through the heart.

Diagram 2

(2)

(d) The graph shows the percentage (%) of adults in the UK who have coronary heart disease.

Age group

(i) Look at the graph.

Which group of people is most at risk of having coronary heart disease in the UK?

...............................................................................................................(2)

(ii) Explain what happens to the heart in coronary heart disease.

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(Total 11 marks)

Q20. The diagram represents the human blood circulation system.

(a) A, B, C and D are blood vessels.

(i) Give the letter of one blood vessel that is an artery. ....................................(1)

(ii) Give the letter of one blood vessel that is a vein. ....................................(1)

(b) A student pedalled an exercise cycle at constant speed for 5 minutes. The student’s heart rate was recorded at one-minute intervals during the exercise. The results are shown in the graph.

(i) What was the student’s heart rate before the exercise began?

................................................ per minute(1)

(ii) How long was it before the student’s heart rate reached 124 beats per minute?

...................................................... .minutes(1)

(c) Which of the following parts of the blood carries most oxygen?

Draw a circle around one answer.

plasma red blood cells white blood cells

(1)(Total 5 marks)

Q21. (a) Respiration is a process which takes place in living cells. What is the purpose of respiration?

.....................................................................................................................................

.....................................................................................................................................(1)

(b) (i) Balance the equation for the process of respiration when oxygen is available.

C6H12O6 + O2 → CO2 + H2O(1)

(ii) What is the name of the substance in the equation with the formula C6H12O6?

..........................................................................................................................(1)

(c) Oxygen is absorbed through the alveoli in the lungs.

(i) How are the alveoli adapted for this function?

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..........................................................................................................................(2)

(ii) Name the gas which is excreted through the alveoli.

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(d) (i) What is the name of the process of respiration when oxygen is not available?

..........................................................................................................................(1)

(ii) Describe the process of respiration which takes place in human beings when oxygen is not available and give an effect.

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(Total 10 marks)

Q22.The diagram shows part of the human digestive system.

(a) Name the parts of the digestive system labelled A, B, C and D.

A ................................................................................

B ................................................................................

C ................................................................................

D ................................................................................(4)

(b) A student has eaten a steak for dinner. The steak contains protein and fat.

(i) Describe how the protein is digested.

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(ii) Explain two ways in which bile helps the body to digest fat.

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(c) A group of students investigated the action of salivary amylase.

The students:

• collected a sample of salivary amylase

• put a different pH solution and 5 cm3 of a food substance in each of 6 test tubes

• added 1 cm3 of salivary amylase to each of the 6 test tubes

• recorded the amylase activity after 10 minutes.

The results are shown in the table.

pH 7 6 5 4 3 2

Amylase activity inarbitrary units 12 10 3 0 0 0

(i) Name the food substance that amylase breaks down.

...............................................................................................................(1)

(ii) Suggest what happens to the breakdown of this substance when food reaches the stomach.

Use information from the table to help you to answer this question.

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(3)

(Total 15 marks)

M1.(a) (i) capillary1

(ii) diffusion1

(b) (i) Zignore any names

1

(ii) large / increased surface / areaallow all food absorbed

or to absorb more foodor improved diffusion

1[4]

M2. (a) Bno mark for ÉBÉ, alone

large(r) surface / area or large(r) membraneaccept reference to microvilliaccept reasonable descriptions of the surfacedo not accept wall / cell wallignore villi / hairs / cilia

1(b) (i) any one from:

• insulin / hormoneif named hormone / enzyme must be correct for pancreas

• enzyme / named enzyme1

(ii) many ribosomes1

(ribosomes) produce proteinaccept insulin / hormone / enzyme named is (made of) protein

or

allow many mitochondria (1)

provide energy to build protein or to make protein (1)accept ATP for energy

1[4]

M1. (a) area of strips / length of transects / number of transects1

(b) (i) since squirrels are mobile and could be missed / counted twice

1

(ii) numbers of larders observed likely to be lower than actualdo not accept squirrels share larders or squirrels have more than one larder

1

since unlikely that all could be spotted if 5 m away or

old larders or

squirrels moved on / died1

(c) (no)

the bars show the range of the number of squirrel larders inthe different types of woodland

1

although spruce woodlands have the larger ranges, somespruce woodlands will have very low numbers of larders

1[6]

M4. (a) (i) light or solardo not credit sun’s energydo not credit radiant

1

(ii) chlorophyll1

(iii) chloroplast1

(iv) CO2 + H2Oreactants identified (accept words)

1

C6H12O6 + O2

products identified (accept words)1

6CO2 + 6H2O → C6H12O6 + 6O2

balanced equation1

(b) any two from:

increased CO2 concentration

increased water supply

increased temperature (up to a point)increased light intensity

do not accept heat or warmth

altered light quality by less green orincreasing other colours

2

(c) any four points

• palisade (mesophyll)

• lots of chloroplasts or chlorophyllor main site for photosynthesisor absorb maximum amount of light

• guard cells

• CO2 in or O2 out or water vapourout

• controls size of stoma or pores inleaf

allow stomata4

[12]

M5. (a) (i) tissueextra box ticked cancels the mark

1(ii) organ

extra ring drawn cancels the mark1

(b) (i) Layer Beach extra box ticked cancels 1 mark

1

Layer C1

(ii) (contain) chloroplasts / chlorophyllother parts disqualify

1

(c) two correct = 2 marksone correct = 1 markextra line from a part of a cell cancels the mark

2[7]

M6.

(a) (i) Junefor 1 mark

1(ii) Aprilmax. lightphotosynthesis makes sugars/substances needed for growth

for 1 mark each3

(b) 2 of:temperaturecarbon dioxide availabilitywaterchlorophyll

any 2 for 1 mark each2

[6]

M7. active transport needs energy or diffusion is not energy-dependent1

any three from:

• (energy from) aerobic respiration

• more respiration with O2 or more energy release with O2

• (aerobic) respiration / energy release occurs in mitochondriado not allow anaerobic

• xylose / other sugars absorbed by diffusion / not by active transportallow active transport is selective / specificor active transport can distinguish glucose and xylose

3 [4]

M8. (a) movement of water [1]

from high concentration (of water) to low concentration (of water)orfrom (an area of) dilute solution to an area of concentrated solution [1]

through a differentially or partially or selectively or semi permeablemembrane [1]

3

(b) (i) it will rise1

(ii) water enters visking tubing [1]

because the concentration of water outside is greater than theconcentration insideorbecause the concentration of salt or solute is greater inside the tubing thanoutside [1]orto equalise concentration water has to enter visking tubing [2]

2[6]

M9.(a) (i) any one from:

• (produce) toxins / poisons

• (cause) damage to cellskill / destroy cellsallow kills white blood cells

1

(ii) produce antitoxins1

engulf / ingest / digest pathogens / viruses / bacteria / microorganismsaccept phagocytosis or descriptionignore eat / consume / absorb for engulfignore references to memory cells

1

(b) (i) dead / inactive / weakenedaccept idea of antigen / protein

1

(measles) pathogen / virusignore bacteria

1

(ii) (after infection)accept converse if clearly referring to before vaccination

1rise begins sooner / less lag time

steeper / faster rise (in number)1

longer lasting or doesn’t drop so quicklyidea of staying high for longerignore reference to higher starting point

1

(iii) antibodies are specific or needs different antibodiesaccept antigens are different or white blood cells do not recognise virus

1

(c) reduces spread of infection / less likely to get an epidemicaccept idea of eradicating measles

1[10]

M10. (a) there is a lack of valid / reliable evidence1

because the early organisms were soft bodied or because remains were destroyed by geological action

1

(b) populations of salamanders became isolated / separated1

by areas between mountains1

there was genetic variation in these isolated communities1

natural selection acted differently on these isolated communities1

eventually resulting in interbreeding being no longer possible and so new species have been formed

1[7]

M11. (a) lemur(s)1

(b) gorilla(s)in either order

1

chimpanzee(s)accept chimps

1

(c) (i) (Charles) Darwin

accept (Alfred) Wallaceif first name given it must be correct

1

(ii) variationin this order

1

environmentallow phonetic spellings

1

survive1

generation1

[8]

M12.(a) any three from:

• parts of organisms have not decayedaccept in amber / resinallow bones are preserved

• conditions needed for decay are absentaccept appropriate examples, eg acidic in bogs / lack of oxygen

• parts of the organism are replaced by other materials as they decayaccept mineralised

• or other preserved traces of organisms, eg footprints, burrows and rootlet tracesallow imprint or marking of organism

3

(b) (i) teeth for biting (prey)must give structure + explanation

1

claws to grip (prey)accept sensible uses

1

wing / tail for flight to find (prey)1

(ii) any two from:

• new predators• new diseases• better competitors• catastrophe eg volcanic eruption, meteor• changes to environment over geological time

accept climate changeallow change in weather

• prey dies out or lack of food

allow hunted to extinction2

[8]

M13. (a) kills / destroys bacteria / MRSAdo not allow germs

1

prevents / reduces transferallow stops MRSA entering ward

1

(b) mutationdo not accept antibiotics causes mutation

1

(causes) resistanceallow not effectiveignore immunity

1

to antibiotics1

[5]

M14. (a) any four from:

• mutation / variation

• produces smaller wings / fatter bodymust be linked to mutation / variation

• wings no longer an advantage since no predatorsallow wings / flight not needed as no predators

• wings no longer an advantage since food on groundallow wings / flight not needed as food on ground

• fatter body can store more energy when fruit scarce

• successful birds breed / pass on genes4

(b) any one from:

• evidence has all gone

• no scientists on island at time to record evidence

• no records (from sailors)1

[5]

M15. (a) 4 correct = 4 marks3 correct = 3 marks2 correct = 2 marks1 correct = 1 markextra line from a structure cancels the mark

4

(b) diffusion1

[5]

M16. X – oxygenaccept O2

Y – carbon dioxideaccept CO2

[2]

M17.(a) (i) diffusion1

(ii) carbon dioxideaccept CO2 / CO2do not accept CO2

1

(iii) red blood cells1

(b) 70if no / incorrect answer then70 000 000or280 x 0.25 gains 1 markignore doubling the answer

2

(c) allows more gas / oxygen / CO2

(exchange)do not accept air

1[6]

M18. (a) (i) 19 800for correct answer ignore working or lack of working165 × 120 but no answer / wrong answer = 1 mark (ignore extras)

2

(ii) any two from:

• for respirationignore oxygen debt

• energy releasedallow energy produced

• prevents anaerobic respiration

• prevents build-up of lactic acid2

(b) any two from:

• increased breathing rate(*)

• increased depth of breathing or deep breathing(*)(*)more breathing is max 1 markignore increase in heart rateallow heavier breathingdo not allow harder breathing

• dilation of arteries / vasodilationallow blood vessels dilatedo not allow veins / capillaries dilate

• blood diverted from elsewhereignore name of organ

2[6]

M19.(a) A - atriumignore references to right / left

1

B - ventricle1

(b) (i) muscular1

(ii) push bloodaccept pump / force

1

(c)

arrows approx as indicated

1

arrow(s) showing flow from A to Bfrom B out / up / to artery

1

(d) (i) male1

65 and over1

(ii) fatty deposits / material in (coronary) arteriesallow correct points made about heart attacks

1

narrows / blocks / reduces flow1

decreases oxygen supply (to heart muscle)1

[11]

M20. (a) (i) A or Callow lower case

1

(ii) B or Dallow lower case

1

(b) (i) 601

(ii) 41

(c) red blood cells1

[5]

M21. (a) to transfer / provide / give release energyor production of ATP / adenosine triphosphate (molecules)accept to give heat

1

(b) (i) C6H12O6 + 6O2 → 6CO2 + 6H2Oaccept any othern : 6n : 6n : 6n ratiodo not credit if any other changes have been made

1

(ii) glucosedo not credit sugar / sucrose

1

(c) (i) any two from

large surface

thin (surface)

moist (surface)

(with a good) blood supply2

(ii) carbon dioxideaccept water vapourdo not credit just water

1

(d) (i) anaerobic (respiration)1

(ii) any three from

in mitochondria

glucose decomposes / breaks down / reactsor glucose → lactic acid for (2) marks

to give lactic acid

or breathing hardor lactic acid → CO2 + water

causing pain

(leaving an) oxygen debt

(quick) source of energy

(but) less efficient than aerobic respirationaccept less efficient than with oxygen

M22.(a) A − saliva(ry) gland1

B − liver1

C − duodenumignore small intestine

1

D − pancreasaccept phonetic spellings

1

(b) (i) any three from:• chewing / muscle contraction / mechanical digestion

allow churning• protease enzymes

allow pepsin / trypsin• in stomach / small intestine / duodenum / from pancreas• (break down protein) into amino acids

allow (poly)peptides3

(ii) neutralises acid pH / makes conditions alkaline1

so lipase can work1

emulsifies fat1

to give large(r) surface area for lipase / enzyme action1

(c) (i) starchignore carbohydrate

1

(ii) breakdown stopsallow slows down

1

because stomach produces / contains acid / has low pH1

and amylase cannot work in acid / low pHaccept amylase is denatured / changes shape

1[15]

mis web view(ii) which word describes a whole leaf? draw a ring around . one. answer ... m16. x...

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