Lesson 3.6.2.1.1

3.6.2.1.1 Resting potential and the action potential Quiz: AQA Biology, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.6.2.1.1, Resting potential and the action potential: 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 approximate value of the resting potential of a neurone?

    • +40 mV
    • -20 mV
    • -70 mV
    • 0 mV

  2. Which ion is at a higher concentration outside the neurone at rest?

    • Potassium
    • Chloride inside only
    • Sodium
    • Calcium inside only

  3. At rest, the membrane of a neurone is more permeable to which ion?

    • Magnesium
    • Potassium
    • Sodium
    • Calcium

  4. What is depolarisation in a neurone?

    • The release of neurotransmitter into a synapse
    • A change making the inside more negative than at rest
    • The return of the membrane to its resting potential
    • A change in membrane potential, making the inside less negative as sodium ions enter

  5. What does the all-or-nothing principle mean for an action potential?

    • An action potential occurs only when the stimulus is removed
    • The size of an action potential depends on the strength of the stimulus
    • An action potential either occurs fully, when threshold is reached, or does not occur at all
    • An action potential is produced continuously while a stimulus is present

  6. What structure in a myelinated motor neurone speeds up nerve impulses?

    • The sarcoplasmic reticulum
    • The cell body only
    • The myelin sheath with nodes of Ranvier
    • The synaptic knob

  7. Which process restores the resting potential after depolarisation?

    • Repolarisation, as potassium ions leave the cell through potassium channels
    • Photolysis of water
    • Acetylcholine binding to the post-synaptic membrane
    • Sodium ions entering the cell through sodium channels

  8. Why is sodium influx during an action potential driven by both concentration and electrical gradients?

    • Sodium is pushed out of the cell by an electrical gradient
    • Sodium is more concentrated outside and the inside is negative, so sodium is pulled inwards
    • Sodium is more concentrated inside and the inside is positive
    • Sodium is always stored in the myelin sheath

  9. A stimulus is 20% above threshold. What is the size of the resulting action potential?

    • Twenty per cent larger than the threshold response
    • The same as a stimulus just above threshold, because the response is all or nothing
    • Zero, because stimuli above threshold do not produce action potentials
    • Half the normal size, to protect the neurone

  10. A neurone's membrane moves from -70 mV to +40 mV at the peak of an action potential. What is the total change in potential?

    • 40 mV
    • 30 mV
    • 70 mV
    • 110 mV

  11. Which mechanism maintains the concentration differences of sodium and potassium across the membrane?

    • The sodium-potassium pump, which moves three sodium ions out for every two potassium ions in
    • The myelin sheath, which holds the ions in place
    • Photosynthesis, which generates the ion gradients
    • Acetylcholinesterase, which breaks down the ions

  12. Why does saltatory conduction increase the speed of a nerve impulse?

    • The impulse is faster because the axon has no membrane
    • The impulse jumps from node to node, so depolarisation happens only at the nodes
    • The impulse travels through the myelin sheath without any ions
    • The impulse is faster because the sodium pump works more slowly

  13. Why does a larger axon diameter increase the speed of conduction?

    • There are more sodium pumps per unit area
    • There is less resistance to the flow of local currents along the axon
    • The resting potential is larger
    • There is more myelin on the axon

  14. How does a fall in temperature affect the speed of conduction along a neurone?

    • It slows conduction, because ion movement and channel activity become slower
    • It has no effect because conduction does not involve ion movement
    • It speeds conduction, because cold makes ions move faster
    • It stops conduction permanently

  15. Why is the inside of a neurone negative at rest, even though small numbers of ions move across the membrane?

    • The sodium-potassium pump moves more sodium out than potassium in, and the membrane leaks more potassium out
    • The inside of a neurone contains no ions at all
    • The resting neurone has no membrane
    • The outside of the neurone is strongly negative

  16. Which change in membrane permeability causes depolarisation?

    • A large increase in permeability to potassium ions
    • A large increase in permeability to sodium ions
    • A large decrease in permeability to all ions
    • A change in permeability only to chloride ions

  17. A nerve impulse is transmitted with a constant size, but a strong stimulus produces more impulses per second. How is stimulus intensity signalled?

    • By the size of each action potential
    • By the speed of the cell body
    • By the frequency of action potentials
    • By the number of myelin sheaths

  18. Loss of the myelin sheath in disease would most likely cause what change in nerve conduction?

    • No change, because myelin does not affect conduction
    • A larger resting potential
    • Slower conduction, because saltatory conduction is lost
    • Faster conduction, because the axon becomes more permeable

  19. Which ion channels open first during the depolarisation phase of an action potential?

    • Voltage-gated sodium channels
    • Chloride channels only
    • Calcium channels in the myelin sheath
    • Potassium channels in the myelin sheath

  20. Which statement correctly describes hyperpolarisation?

    • The inside of the membrane becomes more negative than the resting potential
    • The inside of the membrane becomes less negative than the resting potential
    • The membrane returns to resting potential in a single step
    • Sodium ions are pumped into the cell by the membrane

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