Survival and response, Nerve impulses, Synaptic transmission, Receptors and Control of heart rate AQA A2 Biology - EXAM QUESTIONS

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Q1. This question should be written in continuous prose, where appropriate.

(a) Explain how a resting potential is maintained in a neurone.

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(b) In an investigation, an impulse was generated in a neurone using electrodes. During
transmission along the neurone, an…

Page 2

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(i) Use the graph to estimate the time between the maximum depolarisation and
the start of contraction by the muscle cell.



Time ................................ ms
(1)




(ii) Use your answer to part (i) to calculate the speed of transmission along this
neurone to the muscle cell. Give your answer in mm…

Page 3

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(d) Use your knowledge of the processes occurring at a neuromuscular junction to
explain each of the following.

(i) The cobra is a very poisonous snake. The molecular structure of cobra toxin is
similar to the molecular structure of acetylcholine. The toxin permanently
prevents muscle contraction.

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Figure 1 Figure 2




(i) Explain why it takes time for the rod cells to recover their sensitivity to light after
moving into darkness.

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(2)




(ii) Use information in F igures 1 and 2
to explain the differences in sensitivity of rod
cells to red and…

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(1)
(Total 5 marks)




Q3. S In an investigation, the effects of caffeine on performance during exercise were
measured. One group of athletes (A ) was given a drink of decaffeinated coffee.
Another group (B) was given a drink of decaffeinated coffee with caffeine added.
One hour later the…

Page 6

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(b) (i) Describe the effect of caffeine on exercise performance.

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(ii) Suggest one e xplanation for the higher glycerol and fatty acid concentrations
in the blood plasma of the athletes after they were given caffeine.

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(c) The researchers measured the volumes of…

Page 7

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(ii) The researchers found that, when the athletes were given the drink containing
caffeine, their mean RQ was 0.85. When given the drink without caffeine their
mean RQ was 0.92.

The researchers concluded that when the athletes had caffeine they used
glycogen more slowly than when they did not have…

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(b) Explain what causes the conduction of impulses along a non-myelinated axon to be
slower than along a myelinated axon.

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(Total 5 marks)




Q5. S In an investigation by a student into the responses of maggots, the bottom of a…

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The experiment was repeated three more times. The total number of maggots in
each segment from the four experiments is shown in the table.

Colour of Intensity of reflected light /
Total number of maggots
segment arbitrary units
Black 4 154
Red 25 229
Blue 10 178
White 44 47…

Page 10

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(1)
(Total 4 marks)




Q6. When a finger accidentally touches a hot object, a reflex action occurs. The biceps
muscle contracts, causing the arm to be flexed and the finger is pulled away. The diagram
shows the arrangement of the bones in the arm, the muscles used for flexing…

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