Lesson 3.6.2.1.2

3.6.2.1.2 Refractory period and transmission of nerve impulses Quiz: AQA Biology, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.6.2.1.2, Refractory period and transmission of nerve impulses: 20 multiple choice questions for the AQA Biology (7402), Unit 6: Organisms respond to changes in their internal and external environments, written with Revision Ninja.

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The 20 questions

  1. What is the refractory period of a neurone?

    • A period after an action potential when the membrane cannot fire again, or needs a stronger stimulus to do so
    • The period during which the neurone is at its resting potential only
    • The time taken for a neurotransmitter to cross the synaptic cleft
    • The time taken for a muscle to contract after a stimulus

  2. Why does the refractory period make nerve impulses discrete?

    • It increases the size of each action potential
    • It separates successive action potentials so that they are transmitted as distinct impulses
    • It makes all impulses travel at the same speed
    • It prevents depolarisation from ever starting

  3. Which role does the refractory period play in transmission of impulses?

    • It limits the maximum frequency at which impulses can be transmitted
    • It makes impulses travel in both directions
    • It stops the impulse reaching the synapse
    • It increases the speed of impulses above the maximum

  4. Why can an impulse travel in only one direction along an axon?

    • Potassium ions travel only forwards along the axon
    • Myelin prevents depolarisation in both directions
    • The region behind the moving impulse is refractory and cannot be depolarised again
    • The sodium pump moves ions in one direction only

  5. Which three factors affect the speed of conduction along a neurone?

    • Axon length, number of synapses and colour of the axon
    • Myelination, axon diameter and temperature
    • Receptor number, hormone levels and blood pressure
    • Myelination, number of mitochondria and pH only

  6. What is saltatory conduction?

    • The jumping of neurotransmitter across a synaptic cleft
    • The jumping of an action potential from one node of Ranvier to the next along a myelinated axon
    • The movement of sodium ions through the sodium pump
    • The rapid movement of an impulse through blood vessels

  7. A neurone has a refractory period of 2 ms. What is the maximum frequency of impulse transmission?

    • 500 impulses per second
    • 200 impulses per second
    • 2 impulses per second
    • 0.002 impulses per second

  8. A neurone has a refractory period of 5 ms. What is the maximum frequency of impulses?

    • 200 impulses per second
    • 5 impulses per second
    • 500 impulses per second
    • 50 impulses per second

  9. An impulse travels 1.5 m along an axon in 5 ms. What is the speed of conduction?

    • 3000 m per second
    • 7.5 m per second
    • 0.3 m per second
    • 300 m per second

  10. An impulse takes 10 ms to travel 2 m along a neurone. What is its speed?

    • 0.2 m per second
    • 200 m per second
    • 5 m per second
    • 20 m per second

  11. A neurone conducts at 50 m per second. How long does an impulse take to travel 0.5 m?

    • 1 ms
    • 100 ms
    • 10 ms
    • 25 ms

  12. Which combination of features would produce the fastest conduction?

    • No myelin, small diameter and a cold temperature
    • Myelination, small diameter and a cold temperature
    • Myelination, large axon diameter and a warm temperature within the normal range
    • No myelin, large diameter and a cold temperature

  13. Why does a neurone with a longer refractory period have a lower maximum firing frequency?

    • Longer refractory periods speed up impulse conduction
    • Longer refractory periods make the resting potential more negative
    • Each impulse must wait for the refractory period to end before another can be generated
    • Longer refractory periods increase the number of sodium pumps

  14. Why does cooling a neurone reduce the maximum frequency of impulses it can transmit?

    • Cooling makes the resting potential less negative
    • Cooling slows the ion movements and channel responses, so the impulse and recovery take longer
    • Cooling removes myelin from the axon
    • Cooling increases the number of sodium channels

  15. Why do myelinated neurones conduct faster without needing a larger diameter?

    • Myelin increases the number of sodium channels along the whole axon
    • Myelin makes the membrane more permeable to potassium at all points
    • Myelin removes the refractory period entirely
    • Action potentials are regenerated only at the nodes, so the impulse jumps between them

  16. Which statement best explains why a neurone cannot fire a second action potential immediately after the first?

    • The sodium pump has been removed from the membrane
    • The neurone is full of neurotransmitter
    • The membrane is refractory while ion channels reset and the resting potential is restored
    • The neurone has used up all its ATP

  17. Calculate the maximum frequency of impulses for a neurone whose refractory period is 0.25 ms.

    • 0.25 impulses per second
    • 250 impulses per second
    • 40 impulses per second
    • 4000 impulses per second

  18. Why is the refractory period described as limiting the frequency of impulse transmission?

    • It sets the shortest possible interval between successive action potentials
    • It controls the number of synapses in a neurone
    • It sets the size of each action potential
    • It sets the longest possible interval between successive action potentials

  19. A neurone fires at its maximum frequency of 250 impulses per second. What is the minimum time between successive impulses?

    • 4 ms
    • 250 ms
    • 40 ms
    • 0.25 ms

  20. Which statement about the refractory period is correct?

    • It follows each action potential, during which the ion channels reset
    • It occurs before each action potential and triggers it
    • It is the time taken for a synapse to clear its transmitter
    • It is the period during which neurotransmitter is made in the cell body

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