Q1.          Plant plankton are aquatic microscopic organisms that photosynthesise. The graph shows the numbers of plant plankton in the North Sea at different times of the year.

Use the data and your knowledge of photosynthesis and growth to explain:
(a)     why numbers of plant plankton were low in winter but increased rapidly during the spring,
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(b)     the reduction in numbers of plant plankton in the early summer.
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(Total 4 marks)

Q2.          The temperature in a sauna is much hotter than core body temperature.
A woman sits in a sauna.
The high temperature of the sauna causes the woman’s core body temperature to rise.
(a)     When the woman’s core body temperature rises, the woman’s rate of sweating increases.
Explain why.
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(b)     The woman comes out of the sauna.
The woman’s skin looks redder than when she went into the sauna.
Describe what happened to the blood circulation in her skin to cause this change in colour.
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(2)
(c)     After coming out of the sauna the woman gets into a bath of icy water.This makes the woman shiver.
(i)      What process brings about shivering?
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(1)
(ii)     Shivering increases body temperature.
Explain how.
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(2)
(Total 7 marks)

Q3.          Emphysema is a disease of the lungs. People who smoke cigarettes are more likely to suffer from emphysema. The diagrams show lung tissue from a healthy person and lung tissue from a person with emphysema. The diagrams are drawn to the same scale.

Lung tissue from a healthy person         Lung tissue from a person with emphysema
          Explain how emphysema reduces the amount of oxygen which diffuses into the blood
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(Total 2 marks)
 Q4.          One group of scientists is working in a hot desert and another group is working in a tropical rainforest.
The table shows information about the scientists and the conditions in the desert and the rainforest.
Information	Hot desert	Rainforest	
Mean core body temperature of
scientists in °C	37.3	38.9	
Air temperature in °C	36.0	35.5	
Mean percentage concentration
of moisture in the air	9.0	92.0	
Mean wind speed at ground level
in metres per second	12.0	3.0	
(a)     Both groups of scientists are doing similar jobs. The jobs cause the scientists to sweat a lot.
Use information from the table to explain the difference in the mean core body temperature of the two groups of scientists.
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(2)
(b)     Changes to blood vessels in the skin help to decrease body temperature.
Explain how.
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(2)
(Total 4 marks)
Q5.          The pictures show three mammals and their average body temperature in °C.
Hamster                                     Horse                                         Sheep

36.8 °C                                      38.0 °C                                        39.2 °C
NOT TO SCALE
  Describe three different ways by which most mammals are able to maintain a constant body temperature when the temperature of the environment falls.
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(Total 6 marks)
Q6.          (a)     Each day, a boy ate food containing 12 000 kilojoules of energy. The boy’s body used 80 per cent of this energy to maintain his core temperature.
(i)      Name the process which releases energy from food.
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(1)
(ii)     Calculate the amount of energy that the boy would use each day to maintain his core body temperature. Show clearly how you work out your final answer.
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Amount of energy used each day = ........................... kJ
(2)
(b)     The diagram shows a section through human skin.

          Explain how structure A helps to cool the body on a hot day.
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(3)

(c)     Body temperature is monitored and controlled by the thermoregulatory centre. Where in the body is the thermoregulatory centre?
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(1)
(Total 7 marks)
 
Q7.          Some recreational drugs are dangerous.
Class A drugs include heroin and cocaine. Class A drugs are very addictive.
(a)     It is difficult to stop using addictive drugs. Explain why.
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(b)     As part of the British Crime Survey, a large, random selection of the UK population is interviewed in their own home about drug use.
People in the sample:
•        answer questions about drug use
•        answer questions on a lap top
•        do not give their names.
The bar chart shows the percentages of people aged 16-59 by age group who reported using any Class A drug ever, in the previous year and in the previous month.

(i)      Describe how the percentage of people who have ever used Class A drugs is related to age.
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(2)
(ii)     The percentage of people who reported using Class A drugs in the previous month is highest amongst 16 -29 year-olds.
Suggest two reasons for this.
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(2)

(iii)    The data in the bar chart is unlikely to be completely accurate.
Explain why.
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(2)
(Total 8 marks)
 Q8.          During exercise an athlete’s core body temperature may rise.
(a)     What causes this rise in core body temperature?
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(1)
(b)     During a long race one athlete did not drink any liquid. Towards the end of the race the amount of sweat he produced began to fall.
(i)      This athlete’s core body temperature increased more than that of other similar athletes who had drunk enough liquid during the race.
         Explain why.
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(2)

(ii)     Describe one other way in which this athlete’s body would respond in order to reduce core body temperature.
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(2)

(c)     The graph shows the effects of showering for ten minutes at 15 °C and at 35 °C on core body temperature after a long race.

          Suggest an explanation for the differences in core body temperature:
(i)      between 0 and 2 minutes
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(ii)     between 4 and 10 minutes.
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(Total 8 marks)
 
Q9.          A walker falls through thin ice into very cold water.

The walker’s core body temperature falls. He may die of hypothermia (when core body temperature falls too low).
(a)     (i)     Which part of the brain monitors the fall in core body temperature?
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(1)
(ii)     How does this part of the brain detect the fall in core body temperature?
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(2)
(b)     While in the water the walker begins to shiver.
Shivering helps to stop the core body temperature falling too quickly.
Explain how.
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(2)
(c)     The walker had been drinking alcohol.
Alcohol causes changes to the blood vessels supplying the skin capillaries, making the skin look red.
(i)      Describe the change to the blood vessels.
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(1)

(ii)     The walker is much more likely to die of hypothermia than someone who has not been drinking alcohol.
Explain why.
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(2)
(Total 8 marks)
 Q10.          Many recreational drugs harm the body.
          Some people become dependent on a recreational drug.
What happens to people’s bodies when they become dependent on a drug?
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(Total 2 marks)
Q11.          The brain and the skin are involved in monitoring and controlling body temperature.
(a)     Describe the parts played by the brain and the skin in monitoring body temperature.
(i)      The brain
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(2)
(ii)     The skin
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(1)

(b)     The diagram shows a section through part of the skin.
          The muscle labelled X controls the flow of blood into the skin capillary. When muscle X contracts, the flow of blood into the skin capillary is reduced.

Explain the role of muscle X in the control of body temperature.
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(Total 6 marks)
 Q12.          Read the description of an investigation into the link between smoking cannabis and heroin addiction.
 Six ‘teenage’ rats were given a small dose of THC – the active chemical in cannabis – every three days between the ages of 28 and 49 days. This is the equivalent of human ages 12 to 18.
The amount of THC given was roughly equivalent to a human smoking one cannabis ‘joint’ every three days.
A control group of six ‘teenage’ rats did not receive THC.
After 56 days catheters (narrow tubes) were inserted in all twelve of the now adult rats and they were able to self-administer heroin by pushing a lever.
All the rats began to self-administer heroin frequently. After a while, they stabilised their daily intake at a certain level.
The ones that had been on THC as ‘teenagers’ stabilised their heroin intake at a much higher level than the others. They appeared to be less sensitive to the effects of heroin. This pattern continued throughout their lives.
Reduced sensitivity to the heroin means that the rats take larger doses. This has been shown to increase the risk of addiction.	
 Evaluate this investigation with respect to establishing a link between cannabis smoking and heroin addiction in humans.
Remember to include a conclusion to your evaluation.
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(Total 5 marks)
M1.        (a)     light and/or temperature too low in winter, 
increasing light in spring leads to increase in photosynthesis
increasing temperature in spring leads to increasing metabolism/
growth/reproduction
for 1 mark each
3
(b)     they run out of minerals
for 1 mark
1
[4]
 M2.          (a)     any two from
•        reference to role of thermoregulatory centre detecting rise in
temperature (of blood or skin) or / causing increase in sweating
•        more evaporation
need to refer to more at least once to gain both marks
•        more cooling / heat loss
without reference to more only award max 1 mark if both ideas given, eg cooling alone gets no marks
2
(b)     blood vessels supplying (skin) capillaries
do not accept capillaries / veins
1

or
arteries
or
arterioles
1
dilate / widen
allow vasodilation
do not accept idea of blood vessels moving
note: marks are awarded independently
accept shunt vessels close for 2 marks
1

(c)     (i)      muscle contraction
ignore relaxing
do not allow vasoconstriction
1

(ii)     respiration
(respiration) releases / produces heat
reference to respiration is required for this mark
1
[7]
 M3.          thicker surface
1
          reduced surface area
accept fewer alveoli
1
[2]
 M4.          (a)     in rainforest:
accept converse
(water from) sweat does not evaporate (as much) 
max 1 if not clear whether desert or rainforest
1

any one from:
•        (due to) less wind / higher moisture / humidity
•        less cooling effect
ignore references to temperature
1

(b)     blood vessels supplying capillaries dilate / widen or vasodilation 
do not award mark if candidate refers only to blood vessels dilating or to capillaries dilating. 
accept ‘arteries’ or ‘arterioles’ for ‘blood vessels supplying, capillaries’ but do not accept ‘veins’.
ignore expand / get bigger / relax / open
do not accept idea of blood vessels moving
1

more blood (through skin / surface capillaries) leads to greater heat loss
1
[4]
 M5.          vasoconstriction/blood vessels near surface get narrower/decreased blood
supply near surface of the skin or closing sweat pores
any three pairs. 2 marks for each pair of features and explanations up to a maximum of 6 marks
          (which) prevents the heat being lost from the blood/prevents heat lost due
to evaporation
explanation must match feature to score the second mark

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          hair/fur stands on end or goosepimples
          (this) increases the insulation effect

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          shivering/increased muscular activity/movement/increased metabolism
          (this) generates heat
do not accept raise body temperature
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          behavioural changes/find somewhere warm/put on clothes / huddling /
hibernate / grow extra fat / fur
          (this) prevents/reduces heat loss
do not accept keep warm
[6]
M6.          (a)     (i)      respiration
1
(ii)     9600
if correct answer, ignore working / lack of working
 for 1 mark
2

(b)     any three from:
•        dilates / widens or muscle in wall relaxes or sphincter opens
do not accept expands or just gets bigger
•        more blood flows near skin surface or more blood through capillaries
•        heat lost by radiation / convection / conduction
ignore evaporation
•        heat loss from blood / cools blood
3

(c)     hypothalamus / brain
1
[7]
 M7.          (a)     alters chemical reaction in the body
or changes brain / body functioning
or brain / body does not function correctly without drug
ignore references to dependence
1

withdrawal symptoms
allow crave / craving
1

(b)     (i)      (rises to a) maximum at 25-29 / 30-34 / 25-34
1

(falls to) minimum at 55-59
if neither mark gained allow 1 mark for indicating high usage anywhere in the 20-44 range
1

(ii)     any two from reference to eg:
ignore references to maturity / disposable income / stress
•        (peer) pressure / fashionable
•        experiment / try new things
•        ease of obtaining drugs
2

(iii)    some people will be dishonest / afraid to admit use
ignore sample not accurate
1

(because) class A drugs illegal
or because they will get into trouble
1
[8]
 M8.          (a)     respiration
allow muscle contraction or muscle movement or exercise of muscles
allow metabolism / chemical reactions
1

(b)     (i)      any two from:
•        less / no water (available) for sweat
allow dehydrated so less sweat
allow converse if evident that response refers to athletes who have drunk liquid
•        less / no heat lost / less / no cooling
only need to refer to less / no once
•        less / no evaporation (of sweat)
2
(ii)     either
         blood vessels supplying the skin or
blood vessels in skin
do not allow first mark if implied that
skin capillaries dilate
1
         dilate / widen / muscles relax
ignore enlarge / open
vasodilation in skin = 2 marks
allow hairs lie flat for 1 mark
allow less insulation for 1 mark if linked to hairs
allow more blood in skin for 1 mark if no other marks awarded
1

(c)     (i)      cold / 15°C cools the body / blood (more)
or reverse argument
ignore reference to values for body temperature derived from graph
1
(ii)     any two from:
•        cools slower at 15oC cold / 15oC
allow converse arguments
•        cold / 15oC causes reduced blood flow to surface / skin
ignore reference to capillaries
•        blood not cooled as much / as quickly
•        cold / 15oC causes shivering
•        muscles contract / more respiration / heat made
2
[8]

 

M9.         (a)      (i)     thermoregulatory centre
allow thermoregulation centre
allow hypothalamus
1

(ii)     it has receptors
ignore receptors in skin
1

reference to temperature of blood
allow plasma for blood
1

(b)     muscles contract
ignore relax / expand
1

increased respiration or more heat released
allow more heat produced
if more not given allow respiration releases / produces heat
1

(c)     (i)      (blood vessels / arteries / arterioles) dilate / widen
do not accept capillaries dilate
ignore blood vessels get bigger / expand
do not accept idea of blood vessels moving
1

(ii)     more blood close to / near surface
allow blood is closer to the surface
do not accept idea of blood vessels moving
1

more heat lost or heat lost faster or cools faster
do not allow for idea of evaporation
1
[8]

M10.          drugs alter chemical processes in body
1

person suffers withdrawal symptoms without drug
1

M11.          (a)     (i)      thermoregulatory centre (in brain)
accept hypothalamus
1
         (receptors sensitive to/measures) temperature of blood
1

(ii)     any one from:
•        receptors (in skin)
•        (skin) sends information / signals / impulses / messages
to brain / thermoregulatory centre
1

(b)     any three from:
          (cold conditions)
•        muscle (X) contracts when cold
•        no / less blood through capillaries
•        no / less heat lost / radiated
•        no / less sweat produced
          (hot conditions)
•        muscle (X) relaxes/does not contract when hot
NB X contracts when cold and relaxes when hot = 2 marks
•        (more) blood through capillaries
•        more heat lost / radiated
•        more sweat produced
all other points must be clearly identified by correct conditions
max 2 if idea of capillaries moving but ignore capillaries dilate
3
[6]
M12.          any five from:
maximum 4 marks if no conclusion
          pros eg
maximum three pros
•        used ‘teenage rats’ as equivalent to human teenagers
•        THC dose typical of human cannabis smoking habits
•        used control group
•        rats allowed to choose amount of heroin
          cons eg
•        sample size small / only used 12 rats
ignore cruelty
•        heroin administration very different from human situation
          conclusions
•        rats given THC / cannabis took more heroin
•        (this) is evidence for a link between THC / cannabis and heroin
•        (but) rat behaviour / physiology not necessarily same as human
behaviour / physiology
•        does not prove link in humans
allow results not reliable for humans
[5]