Q1.
The circulatory system includes the heart, blood vessels and blood.
(a)  The heart pumps the blood in a double circulatory system.
Describe what is meant by a ‘double circulatory system’.
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(2)
(b)  Heart rate is controlled by a group of cells that act as a pacemaker.
Where in the heart is the pacemaker found?
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(1)
(c)  Which blood vessel carries deoxygenated blood?
Tick (✓) one box.
 
Aorta		
Coronary artery		
Pulmonary artery		
Pulmonary vein		
(1)
The structure of a vein is different from the structure of an artery.
One difference is that veins have valves but arteries do not have valves.
(d)  Explain why veins have valves, but arteries do not.
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(2)
(e)  Describe two structural differences between a vein and an artery.
Do not refer to valves in your answer.
1  _________________________________________________________________
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2  _________________________________________________________________
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(2)
(Total 8 marks)
Q2.
This question is about the heart.
(a)  Why is the heart described as an organ?
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(1)
(b)  Valves in the heart keep the blood flowing through the heart in one direction.
The diagram below shows the heart with one of the valves labelled.
 
Explain the effects on a person if the valve labelled in the figure above developed a leak.
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(4)
(c)  Faulty heart valves can be replaced using biological or mechanical valves.
The faulty valve is replaced during an operation.
Biological valves:
•   are from animals or human donors
•   allow blood to flow through them normally
•   wear out and stiffen over time, so may need to be replaced.
Mechanical valves:
•   are made from synthetic materials
•   may cause blood clots on the surface of the valve
•   require anti-clotting drugs to be taken for the rest of the patient’s life
•   can last for a very long time in ideal conditions.
A young woman enjoys extreme sports and would like to start a family.
The woman needs a heart valve replacing.
Describe the advantages and disadvantages for this young woman of having a biological heart valve instead of a mechanical heart valve.
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(4)
(Total 9 marks)
Q3.
The figure below shows the human heart.

(a)  Which blood vessel transports blood with the highest oxygen concentration into the heart?
Tick (✓) one box.
 
A		B		C		D		
(1)
(b)  Blood pressure is a measure of the force of the blood against the walls of the blood vessels.
Which blood vessel transports blood at the highest pressure?
Tick (✓) one box.
 
A		B		C		D		
(1)
(c)  What is the correct order for blood flowing through the heart to the lungs?
Tick (✓) one box.
 
left atrium → left ventricle → pulmonary artery		
left atrium → left ventricle → pulmonary vein		
right atrium → right ventricle → pulmonary artery		
right atrium → right ventricle → pulmonary vein		
(1)
Every year thousands of people in the UK have heart attacks.
A heart attack is caused when the heart muscle cells do not get enough oxygen, causing the cells to die.
(d)  Statins and stents are two treatments used to reduce the risk of someone having a heart attack.
Evaluate the use of statins compared with the use of a stent to reduce the risk of a heart attack.
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(6)
(e)  Many people who survive a heart attack get out of breath easily when they exercise gently.
Explain why heart attack survivors get out of breath easily.
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(4)
Scientists have developed patches of beating heart cells to repair damaged heart tissue.
The patches are placed onto areas of the heart where cells have died. New cells grow to replace the dead cells.
The patches are made using a person’s own cells that are converted into stem cells.
(f)   Explain why stem cells are used to make the patches.
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(2)
(g)  The scientists could have used human embryonic stem cells to make the patches.
Give two advantages of using stem cells made from the person’s own cells, rather than using embryonic stem cells.
1   ________________________________________________________________
___________________________________________________________________
2   ________________________________________________________________
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(2)
(Total 17 marks)
Q4.
 The villi of the small intestine absorb the products of digestion.
The diagram shows two villi. It also shows parts of some of the surface cells of a villus, as seen with an electron microscope.
 
Describe and explain how the villi are adapted to maximise the rate of absorption
of the products of digestion.
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(Total 5 marks)
Q5.
Fresh milk is a mixture of compounds including fat, protein and about 5 % lactose sugar. Lactose must be digested by the enzyme lactase, before the products can be absorbed.
Lactase can be added to fresh milk to pre-digest the lactose. This makes ‘lactose-free’ milk, which is suitable for people who do not produce enough lactase of their own.
A student investigated the effect of changing pH and temperature on the digestion of lactose in milk.
The results are shown in Tables 1 and 2.
 
Table 1
Effect of pH	 	Table 2
Effect of temperature	
pH	Time taken to digest lactose in minutes	 	Temperature in °C	Time taken to digest lactose in minutes	
4.0	20	 	30	20	
5.0	18	 	35	14	
6.0	13	 	40	11	
7.0	7	 	45	6	
8.0	5	 	50	12	
9.0	6	 	55	23	
(a)     The label on a carton of lactose-free milk states:
‘Lactase is normally produced in the stomach of mammals.’
The results in Table 1 show that this statement is unlikely to be true.
Explain how.
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(2)
(b)     Explain as fully as you can the results shown in Table 2.
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(3)
(c)     Bile is produced in the liver and is released into the small intestine.
Explain how bile helps the digestion of milk.
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(2)
(Total 7 marks)
Q6.
Amylase is an enzyme that digests starch.
(a)  Which organs in the human digestive system produce amylase?
Tick (✓) one box.
 
Liver, small intestine and large intestine		
Salivary glands, stomach and liver		
Salivary glands, pancreas and small intestine		
Stomach, pancreas and large intestine		
(1)
A student investigated the effect of pH on the activity of amylase.
This is the method used.
1.   Prepare amylase solution at pH 5
2.   Mix the amylase solution with starch in a boiling tube.
3.   Remove a drop of the amylase-starch mixture every 30 seconds and test it for the presence of starch.
4.   Record the time when all the starch has been digested.
5.   Repeat steps 1 to 4 using amylase solution prepared at pH 6, then at pH 7 and then at pH 8
(b)  What was the independent variable in this investigation?
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(1)
(c)  Describe how the student would know when all the starch had been digested.
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(1)
(d)  Figure 1 shows the student’s results.
Figure 1
 
What was the optimum pH for the amylase?
Use Figure 1.
Optimum pH = _______________
(1)
A scientist did a different investigation.
This is the method used.
1.   Prepare amylase solution at the optimum pH.
2.   Mix the amylase solution with starch in a boiling tube.
3.   Measure the concentration of sugar every 10 seconds for 2 minutes.
Figure 2 shows the scientist’s results.
Figure 2
 
(e)  How much time did it take for the amylase to digest all the starch?
Use Figure 2.
Time to digest all the starch = _______________ seconds
(1)
(f)  Determine the rate of sugar production per minute at 40 seconds.
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Rate = _______________ arbitrary units per minute
(4)
(g)  Explain how the structure of enzyme molecules is related to the effect of pH on the activity of amylase.
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(6)
(Total 15 marks)
Q7.
Amylase is an enzyme that digests starch in the digestive system.
(a)  Explain why starch has to be digested.
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(2)
A student used a colorimeter to investigate the rate of starch digestion.
A colorimeter measures the percentage of light passing through a liquid.
The darker the colour of the liquid, the less light passes through.
The student:
•   mixed 1 cm3 of starch suspension with 10 cm3 of iodine solution
•   measured the percentage of light passing through the mixture
•   repeated with different concentrations of starch suspension.
Figure 1 shows the results.
Figure 1

(b)  Suggest what liquid was used for the test with 0 g/dm3 starch concentration.
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(1)
(c)  Explain the change in the percentage of light passing through the different concentrations of starch suspension in iodine solution.
Use Figure 1.
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(3)
The student then investigated the rate of starch digestion using amylase.
This is the method used.
1. Put 10 cm3 of starch suspension into a test tube.
2. Put 5 cm3 of amylase solution into a separate test tube.
3. Put both test tubes into a water bath at 37 °C for 10 minutes.
4. Mix the contents of both test tubes together in a beaker.
5. Put the beaker into the water bath.
6. Remove 1 cm3 of the mixture and add it to 10 cm3 of iodine solution.
7. Measure the percentage of light passing through the liquid.
8. Repeat steps 6 and 7 every minute for 5 minutes.
(d)  The starch suspension and the amylase solution were kept in the water bath for 10 minutes before being mixed together.
Give the reason why.
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(1)
Figure 2 shows the results.
Figure 2

(e)  The concentration of starch at 3 minutes was 0.3 g/dm3.
Calculate the mean rate of starch digestion for the first 3 minutes.
Use Figure 1 and Figure 2.
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Mean rate =  ____________________ g/dm3 per minute
(4)
(f)   The investigation was carried out at pH 7
Explain how the results would be different if the investigation was carried out at pH 1
Use Figure 2.
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(3)
(Total 14 marks)
Q8.
Being overweight can affect the health and life expectancy of a person.
(a)     Give one disease related to being overweight.
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(1)
(b)     Body mass index (BMI) helps to show if a person has a healthy body mass for their height.
BMI is calculated using the equation:

A woman has a BMI of 27 and a body mass of 68.1 kg
Calculate the woman’s height in metres.
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Height = _______________ m
(3)
(c)     The graph below shows a height-body mass chart for adults.

Which weight category describes the woman in part (b)?
Tick (✓) one box.
 
Underweight		
Healthy weight		
Overweight		
Obese		
(1)
(d)     People are encouraged to control their body mass with diet and exercise.
Describe how the balance between the mass of food eaten and the amount of exercise a person does controls body mass.
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(3)
(e)     During long periods of vigorous exercise the body respires anaerobically.
Explain the changes that happen in the body during and after vigorous exercise.
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(6)
(Total 14 marks)
Q9.
This question is about plant transport systems.
(a)  Describe how water is transported from the soil to the atmosphere through a plant.
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(4)
(b)  Dissolved sugars are moved through a plant in phloem tissue.
What is the name of the process that moves dissolved sugars through phloem tissue?
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(1)
Phloem tissue is made of sieve tube cells and companion cells.
The figure below shows a section of phloem tissue.

(c)  Explain one way sieve tube cells are specialised for their function.
Use the figure above.
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(2)
(d)  What does the structure of the companion cells suggest about the process that moves dissolved sugars through the phloem tissue?
Give a reason for your answer.
Use the figure above.
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(2)
(e)  Describe why it is important that dissolved sugars are moved both upwards and downwards in a plant.
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(3)
(Total 12 marks)
Q10.
A leaf is a plant organ.
Figure 1 shows tissues in a leaf.
Figure 1

(a)  Which tissue is the epidermis?
Tick (✓) one box.
 
A		B		C		D		
(1)
(b)  Explain how the spongy mesophyll is adapted for its function.
Use Figure 1.
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(3)
(c)  The xylem is adapted to transport water through a plant.
Explain one way that xylem is adapted for its function.
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(2)
(d)  Figure 2 shows a pair of guard cells around a stoma.
Figure 2

During the day, glucose is made in the guard cells.
Describe how an increase in glucose concentration in the guard cells causes the stoma to open.
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(2)
(Total 8 marks)
Q11.
The leaves of most plants have stomata.
(a)     (i)      Name the cells which control the size of the stomata.
______________________________________________________________
(1)
(ii)     Give one function of stomata.
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______________________________________________________________
(1)
(b)     The image below shows part of the surface of a leaf.
 
The length and width of this piece of leaf surface are both 0.1 mm.
(i)      Calculate the number of stomata per mm2 of this leaf surface.
______________________________________________________________
______________________________________________________________
_______________________ per mm2
(2)
(ii)     A different plant species has 400 stomata per mm2 of leaf surface.
Having a large number of stomata per mm2 of leaf surface can be a disadvantage to a plant.
Give one disadvantage.
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(1)
(c)     A student investigated the loss of water from plant leaves.
The student did the following:
•        Step 1: took ten leaves from a plant
•        Step 2: weighed all ten leaves
•        Step 3: hung the leaves up in a classroom for 4 days
•        Step 4: weighed all ten leaves again
•        Step 5: calculated the mass of water lost by the leaves
•        Step 6: repeated steps 1 to 5 with grease spread on the upper surfaces of the leaves
•        Step 7: repeated steps 1 to 5 with grease spread on both the upper and lower surfaces of the leaves.
All the leaves were taken from the same type of plant.
The table below shows the student’s results.
 
Treatment of leaves	Mass of water the leaves lost in g	
No grease was used on the leaves	0.98	
Grease on upper surfaces of the leaves	0.86	
Grease on upper and lower surfaces of the leaves	0.01	
(i)      What mass of water was lost in 4 days through the upper surfaces of the leaves?
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______________________________________________________________
Mass = ___________ g
(1)
(ii)     Very little water was lost when the lower surfaces of the leaves were covered in grease.
Explain why.
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(3)
(Total 9 marks)
Q12.
Plants have tissues that are specialised for the transport of food and water molecules.
(a)     Which is a description of the role of the xylem?
Tick one box.
 
Transports dissolved sugars using translocation		
Transports starch in the transpiration stream		
Transports water in the transpiration stream		
Transports water using translocation		
(1)
(b)     Which is a description of the role of the pholem?
Tick one box.
 
Transports dissolved sugars in the transpiration stream		
Transports dissolved sugars using translocation		
Transports starch using translocation		
Transports water in the transpiration stream		
(1)
In plants water is lost through stomata.
Figure 1 shows stomata on the lower surface of a leaf.
Figure 1

(c)     Calculate the number of stomata per mm2 for the leaf shown in Figure 1.
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Number of stomata = ____________________ 
(2)
(d)     Most plants have more stomata on the lower surface of a leaf than on the upper surface.
Explain why there are more stomata on the lower surface of a leaf.
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(3)
(e)     Particles can move into and out of cells by different processes.
Figure 2 shows different particles inside and outside a root hair cell.
Figure 2

Explain the processes by which the different particles would enter the root hair cell.
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(6)
(Total 13 marks)

Mark schemes
Q1.
(a)  right ventricle pumps blood to the lungs
allow right side of heart pumps blood to the lungs
1
left ventricle pumps blood around / to the body
allow left side of heart pumps blood to the body
1
if no other marks awarded allow 1 mark for:
(two circuits / pumps) one from heart to lungs and one from heart to body
or
blood passes twice through heart on each circuit
(b)  right atrium
1
(c)  pulmonary artery
1
(d)  valves prevent backflow of blood
allow valves prevent blood from flowing in the wrong direction
1
(because) blood (in veins) is at lower pressure / force (than in arteries)
allow (because) blood travels more slowly (through veins than arteries)
allow converse statements eg blood in arteries is at higher pressure (1)
(so) do not need valves to prevent backflow (1)
1
(e)  any two from:
•   lumen in vein is wider (than in an artery)
•   (wall of vein) has a thinner layer of muscle (tissue)
•   (wall of vein) has a thinner layer of elastic tissue
if neither mark awarded allow 1 mark for:
veins have thinner walls (than arteries)
do not accept reference to cell wall
2
answers must be comparative allow converse statements
ignore reference to valves
[8]
Q2.
(a)  it is made up of (different) tissues (that perform specific functions)
1
(b)  some blood would flow back into the ventricle / heart
allow not all the blood would leave the ventricle / heart allow blood clot (may form in the heart)
do not accept blood would flow back into the right ventricle
1
(so) less oxygenated blood would be pumped to the body
ignore references to glucose
1
cells require oxygen for respiration
or
less aerobic respiration
allow more anaerobic respiration
1
(so) person would become out of breath
(so) lactic acid will build up
or
(so) less energy transferred
allow the idea of lacking energy
do not accept less energy produced / made / created
or
(so) person would be tired
1
(c)  any four from:
(advantages of biological valve):
•   reduced risk of blood clots which could cause heart attack or stroke
•   reduced risk of blood clots during pregnancy / birth
•   reduced risk of bleeding during pregnancy / birth
•   do not need to take anti (blood) clotting drugs
ignore do not need to take blood thinners
allow do not need to take drugs for life
•   no risk to foetus / baby from drugs
•   reduced risk of serious bleeds if in an accident
•   do not need to carry (anti-blood clotting) drugs when travelling
allow problems related to losing / obtaining drugs abroad
•   low risk of rejection / immune reaction
do not credit reference to rejection twice
allow no risk of side effects from drugs
(disadvantages of biological valve):
•   may be rejected
do not credit reference to rejection twice
•   may have to go through surgery more than once
ignore risks from surgery unqualified
•   may have to take immunosuppressant drugs
allow an animal might be killed
•   have to wait for (suitable) donor
max three marks if only advantages or disadvantages of biological valve given
4
[9]
Q3.
(a)  D
1
(b)  C
1
(c)  right atrium → right ventricle → pulmonary artery
1
(d)  Level 3: A judgement, strongly linked and logically supported by a sufficient range of correct reasons, is given.
5−6
Level 2: Some logically linked reasons are given. There may also be a simple judgement.
3−4
Level 1: Relevant points are made. They are not logically linked. 1‒2 AO1
1−2
No relevant content
0
Indicative content
Advantages of statins
•   easy to take or not invasive (procedure)
•   decrease blood cholesterol
•   slow down build-up of fatty materials in arteries
•   maintain blood flow to heart muscle cells
•   low cost (compared to stent operation)
Disadvantages of statins
•   might be side effects of drug eg muscle pain
•   effects take time to happen
•   drug will need to be taken long term
•   might forget to take drug
Advantages of stent
•   blocked artery is held open
•   blood flow to heart muscle cells is increased
•   stent will remain in place for a long time
•   effect of stent is immediate
•   rapid recovery from operation
Disadvantages of stent
•   risk of infection from operation
•   risk of surgery eg heart attack or bleeding
•   risk of thrombosis or blood clot
For Level 3, arguments for and against both treatments are needed.
(e)  heart (muscle) cannot contract / pump as effectively / powerfully
allow heart (muscle) is not as strong
1
(so) less blood pumped out of heart or to body (on each beat / contraction)
ignore reference to rate of blood flow
1
(so) less oxygen (reaches cells / body) for (aerobic) respiration
allow (so) more anaerobic respiration
1
(so) breathing rate increases to supply more oxygen
or
(so) breathing rate increases to repay oxygen debt
allow (so) breathing rate increases to break down lactic acid
1
(f)  stem cells are undifferentiated cells
allow stem cells can differentiate
allow stem cells can develop into different types of cell
ignore stem cells can become specialised
ignore stem cells are not specialised
1
(therefore) can form heart (muscle) cells
allow (therefore) can form muscle cells
1
(g)  any two from:
•   cells will not be rejected
allow converse if clearly referring to embryonic stem cells
•   no risk of damage to embryo
allow no (potential) human life destroyed / damaged
•   adult can give consent
ignore unethical unqualified
ignore religion unqualified
2
[17]
Q4.
D – many microvilli (1)
Ex – provide large surface area (1)
five points made
max 3 descriptions
max 3 explanations
D – many capillaries / good blood supply (1)
Ex – maintain concentration / diffusion gradient or quickly removes food (1) 
D – thin wall / one cell thick surface / capillaries near surface (1)
allow villi are thin
ignore villi are one cell thick
Ex – short distance for food to travel (1)
D – many mitochondria (1)
Ex – provide energy / ATP for active uptake / transport (1)
[5]
Q5.
(a)     stomach is acidic / has low pH
allow any pH below 7
ignore stomach is not alkaline
1
lactase works best / well in alkali / high pH / neutral / non-acidic conditions
allow any pH of 7 and above 
accept works slowly in acid conditions
allow figures from table with a comparison
ignore reference to temperature
1
(b)     any three from
•        (below 45(°C)) increase in temperature increases rate / speed of reaction
•        reference to molecules moving faster / colliding faster / harder / more collisions
•        optimum / best at 45(°C)
allow value(s) in range 41 - 49
•        high temps / above 45(°C) (rate slows due to) denaturation of enzyme /lactase
allow synonyms of denaturation but not killed
denaturation at high and low temperature does not gain this mark
ignore body temperature
ignore references to time / pH
3
(c)     any two from
•        acid neutralised or conditions made neutral / alkali
accept bile is alkaline
•        (allow) emulsification / greater surface area of fat / lipid
allow description of emulsification eg fat is broken down / broken up into droplets
•        enzymes (in small intestine) work (more effectively / better)
allow better for enzymes
2
[7]
Q6.
(a)  salivary glands, pancreas and small intestine
1
(b)  pH (of amylase / solution / buffer)
ignore upper and lower case letters
allow hydrogen ion / H+ concentration
ignore acidity / alkalinity
1
(c)  iodine (solution / reagent) would not turn black / blue-black
allow iodine (solution / reagent) would not turn dark blue / dark purple
ignore iodine solution / reagent would not turn blue / purple
or
iodine solution / reagent would stay orange / brown
allow iodine (solution / reagent) would not change colour
1
(d)  6.8
answer line takes precedence
allow answer in range 6.75 to 6.85
1
(e)  82 (seconds)
answer line takes precedence
allow answer in range 80 to 84 (seconds)
1
(f)  View with Figure 2
tangent drawn at 40 seconds
1
 
eg
(rate =) 
1
calculation of rate at 40 seconds
(rate =) 0.0375 (arbitrary units per second)
allow an answer in the range 0.035 to 0.042 (arbitrary units per second)
1
(0.0375 × 60 =) 2.25 (arbitrary units per minute)
allow an answer in the range 2.1 to 2.5 (arbitrary units per minute)
if no other marks awarded allow 1 mark for
 
5.25 (arbitrary units per minute)
allow an answer in the range 5.175 to 5.25 (arbitrary units per minute) for this mark only
1
(g)  Level 3: Relevant points (reasons/causes) are identified, given in detail and logically linked to form a clear account.
5−6
Level 2: Relevant points (reasons/causes) are identified, and there are attempts at logical linking. The resulting account is not fully clear.
3−4
Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical linking.
1−2
No relevant content 
0
Indicative content
•   enzymes are protein molecules
•   (so) have a 3D structure
•   lock and key theory
•   have an active site
•   (which) has a specific shape
•   shape of active site will only match shape of substrate
•   starch is substrate for amylase
•   at pH values above or below the optimum the shape of active site is changed (in some molecules)
•   (so) substrate can no longer fit the active site
•   at extreme pH values enzyme is denatured
•   (so) shape of active site is changed
•   (so) amylase can no longer digest starch
•   (so) rate of digestion decreases
For Level 3 reference to enzyme structure and effect of pH on enzyme activity are needed
[15]
Q7.
(a)  starch (molecules) are large / insoluble
1
(so) cannot be absorbed (into the blood)
allow (so) cannot pass through the wall of the (small) intestine / gut
allow (so) cannot diffuse into the blood
allow sugar (molecules) are small / soluble (1)
(so) can be absorbed into the blood
or
(so) can pass through the wall of the (small) intestine / gut (1)
1
(b)  (10 cm3 dilute) iodine solution and (1 cm3 of) water
allow (10 cm3 dilute) iodine solution
allow water
ignore iodine unqualified
1
(c)  percentage of light passing through the liquid decreased with increasing starch concentration
allow the more concentrated the starch (suspension) the less light could pass through
1
(because iodine) solution was darker (in colour)
allow (iodine) solution was blacker
allow the more (insoluble) starch the more cloudy the mixture
1
(so) absorbed more light
ignore less light passes through
1
(d)  any one from:
•   to allow them to reach 37 °C
allow to allow them to reach body temperature
•   so they would be at the optimum / same temperature
allow to equilibrate
1
(e)  6.6 (g/dm3)
allow answer in range 6.5 to 6.7 (g/dm3)
1
6.6 - 0.3
or
6.3 (g/dm3)
allow correctly calculated value consistent with range allowed in step 1
1

allow correct subtraction of answer to step 1 minus 0.3 for 6.3 in this equation
1
2.1 (g/dm3 per minute)
allow correctly calculated rate using incorrectly calculated value for 6.3
1
if no other marks awarded allow 1 mark for the concentrations 1.8 and 0.8 (g/dm3
(f)   (at pH 1) shape of active site would be altered
allow (at pH 1) enzyme / amylase would be denatured
1
(so) starch would not be digested
allow (so) enzyme / amylase would not work
allow (so) no reaction would occur
allow (so) reaction would be (a lot) slower
1
(so) percentage of light passing through liquid would stay at 10
allow (so) percentage of light passing through liquid would not change / increase
1
[14]
Q8.
(a)  any one from:
•   (Type 2) diabetes
ignore obesity
do not accept Type 1 diabetes allow cardiovascular disease ignore heart attack / failure
•   (coronary / ischaemic) heart disease / CHD
•   high blood pressure
•   cancer
•   depression
allow (osteo)arthritis
1
(b)
27 = 
1
height2 = 68.1 ÷ 27
or
height2 = 2.522(r) / 2.52 / 2.5
allow height = 
or
allow height = 
1
height = 1.59 (m) allow height =
allow a correctly rounded value
if 2.5 is given in step 2 allow an answer of 1.58 (m)
1
(c)  overweight
answer must be consistent with height calculated in (b)
1
(d)  any three from:
max 2 marks if refer to energy being made / used / produced / created
allow reference to calories / joules for energy
•   increased energy intake if more food eaten
allow increased energy intake if more fat / carbohydrate eaten
allow converse
allow energy taken in when you eat
•   if exercise more, more energy is transferred / released
allow if exercise more, respiration / metabolism increases or is faster
allow converse
allow energy is transferred during exercise
do not accept energy is burnt during exercise
•   if more energy is taken in than is transferred body mass increases
or
if less energy is taken in than is transferred body mass decreases
allow if less energy is transferred than is taken in body mass increases
or
if more energy is transferred than is taken in body mass decreases
•   if energy intake = energy transferred body mass stays the same
if no marks are awarded allow 1 mark for food eaten can increase body mass and exercise can decrease body mass
or
allow 1 mark for if a lot of food is eaten and little exercise is done body mass increases
allow converse
3
(e)  Level 3: Relevant points (reasons/causes) are identified, given in detail and logically linked to form a clear account.
5−6
Level 2: Relevant points (reasons/causes) are identified, and there are attempts at logical linking. The resulting account is not fully clear.
3−4
Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical linking.
1−2
No relevant content
0
Indicative content
During exercise:
•   increased breathing rate
•   increased breath volume
•   (to) take in more oxygen for (aerobic) respiration
•   (and) exhale more carbon dioxide
•   increased heart rate
•   (so) increased blood flow (to muscles)
•   (to) transport oxygen / glucose to respiring cells faster
•   (and) increase rate of carbon dioxide removal
•   glycogen converted to glucose
•   insufficient oxygen supplied (during prolonged vigorous exercise)
•   (so) lactic acid is formed (during anaerobic respiration)
•   (and) an oxygen debt is created
•   (lactic acid causes) muscles become fatigued / tired or (causes) muscles to stop contracting efficiently
•   allow reference to sweating or increased body temperature or vasodilation (during or after exercise)
After exercise:
•   heart rate remains high or heart rate slowly decreases
•   continue to breathe rapidly or breathing rate slowly decreases
•   (to) pay back oxygen debt
•   oxygen debt is the amount of oxygen needed to break down lactic acid
•   (and to) provide more oxygen to react with the lactic acid and remove it from cells
•   (some) lactic acid transported to liver
•   (lactic acid) is converted back into glucose
For Level 3 need reference to:
•   changes during and after exercise
•   lactic acid and its removal.
[14]
Q9.
(a)  (absorbed from soil) by osmosis through root hair (cells)
allow (absorbed from soil) by diffusion through root hair (cells)
1
travels through xylem (vessels) to the leaves
ignore travels upwards in the xylem unqualified
1
lost through stomata (to atmosphere)
1
idea of driven by evaporation / transpiration
ignore evaporation / transpiration unqualified
1
(b)  translocation
1
(c)  have pores in the end walls
allow sap for dissolved sugars
1
(so) dissolved sugars / food / contents can move from cell to cell
or
no nucleus or few / no sub-cellular structures (1)
allow few / no organelles
ignore cells are empty
to maximise space for movement of dissolved sugars / food / contents (1)
allow thick / rigid cell wall (1) to withstand pressure inside cell
1
(d)  any one from: (the process):
•   requires energy
•   is an active process
•   uses active transport
1
(reason) cells have many mitochondria
allow flow of dissolved sugars / food in sieve tube cell is not impeded (1)
(reason) companion cell is flattened (1)
1
(e)  sugars are made in the leaves by photosynthesis
allow glucose for sugar
allow sugars are not made in the root / meristems (by photosynthesis)
1
all cells / tissues need sugar for respiration
allow every cell / tissue needs sugar for respiration
allow whole plant needs sugar as an energy source
1
(sugars) transported to meristems for growth / cell division / mitosis
or
(sugars) transported for storage as starch / fat / oil
1
[12]
Q10.
(a)  A
1
(b)  has (large) air spaces (between cells)
allow has (large) gaps (between cells)
1
(so) gases can diffuse / move through the leaf
allow carbon dioxide or oxygen or water vapour for gases
1
to / from the photosynthetic / palisade / B layer
allow to / from the upper mesophyll
if named gas given for mp 2 direction of movement must be correct
1
if no other marks awarded allow 1 mark for cells have chloroplasts for photosynthesis
(c)  composed of hollow tubes / cells
allow cells are empty
allow no cytoplasm / nucleus / sub-cellular structures
1
(so) no obstruction to water flow
allow (so) water flows easily if linked to hollow tubes
allow to maintain the transpiration stream
OR
has lignin (1)
ignore has thick walls
(to) hold tubes open (1)
or
(to) strengthen the tubes
allow (to) keep water inside xylem
allow (to) make tubes rigid
OR
no end walls (1)
(so) water flows easily (1)
or
(so) water flows continuously
must be linked to an adaptation
allow (so) maintains a constant water flow
allow to maintain the transpiration stream
1
reason must correctly match the structure
(d)  water enters (guard) cells by osmosis
allow water enters (guard) cells because the concentration of water is higher outside the cell than inside the cell
1
cells swell and curve (to open the stoma)
allow cells become turgid and curve (to open the stoma)
allow inner wall of (guard) cell is thicker / stronger or less flexible than outer wall so cells curve (to open stoma)
1
[8]
Q11.
(a)     (i)      guard (cells)
allow phonetic spelling
1
(ii)     any one from:
ignore reference to cells
•        allow carbon dioxide to enter
allow control loss / evaporation of water or control transpiration rate
•        allow oxygen to leave.
allow ‘gaseous exchange’
1
(b)     (i)      200
correct answer gains 2 marks with or without working
allow 1 mark for 0.1 × 0.1 = 0.01 (mm2)
2
(ii)     more / a lot of / increased water loss
allow plant more likely to wilt (in hot / dry conditions)
1
(c)     (i)      0.12
1
(ii)     the lower surface has most stomata
1
stomata are now covered / blocked (by grease)
1
so water cannot escape / evaporate from the stomata
ignore waterproof
to gain credit stomata must be mentioned at least once
1
[9]
Q12.
(a)     transports water in the transpiration stream
1
(b)     transports dissolved sugars using translocation
1
(c)     2/(0.1 × 0.1)
or
2/ 0.01
1
200
an answer of 200 scores 2 marks
1
(d)     cooler around lower surface
1
more humid around lower surface
allow converse argument for upper surface of leaf if qualified
1
(so) less water evaporated
allow less breeze around lower surface
1
(e)     
Level 3: Relevant points (correct processes / explanations) are identified, given in detail and linked logically to form a clear account.	5-6	
Level 2: Relevant points (correct processes / explanations) are identified and there are attempts at logical thinking. The resulting account is not fully clear.	3-4	
Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical thinking.	1-2	
No relevant content	0	
Indicative content
•   water is absorbed by osmosis
•   osmosis is a passive process, or described
•   water in soil is at a higher concentration than inside cell
•   water moves down concentration gradient
•   through a partially permeable membrane
•   phosphate ions absorbed by diffusion
•   diffusion is a passive process, or described
•   phosphate ions are in a higher concentration in soil than inside cells
•   magnesium ions are absorbed by active transport
•   magnesium ions are in lower concentration in soil than inside cells
•   magnesium ions move from an area of lower concentration to an area of higher concentration inside the cells
•   magnesium ions move up the concentration gradient
•   process requires energy
•   energy from respiration	 	
6
[13]