Action Potentials Quiz

What is an action potential?

• A brief change in the distribution of electrical charge across the cell surface membrane

• A chemical reaction in the neurone

• A flow of electrons across the cell membrane

• A constant electrical current in the axon

What triggers the opening of sodium ion channels during an action potential?

• A chemical reaction

• A decrease in temperature

• A stimulus

• An increase in pressure

What is the threshold potential required to trigger depolarisation?

• 0mV

• +30mV

• -55mV

• -70mV

What happens during depolarisation?

• Sodium ions leave the axon

• Sodium ions enter the axon

• The axon becomes more negative

• Potassium ions enter the axon

What is the potential difference reached during an action potential?

• +30mV

• -55mV

• -70mV

• +70mV

What occurs during repolarisation?

• Potassium ions leave the axon

• Sodium ions enter the axon

• The axon becomes depolarised

• The axon becomes more positive

What is hyperpolarisation?

• The axon returns to resting potential

• The axon becomes depolarised

• The axon becomes more positive than the resting potential

• The axon becomes more negative than the resting potential

What restores the resting potential after hyperpolarisation?

• Voltage-gated potassium channels

• Calcium ion channels

• Sodium-potassium pump

• Voltage-gated sodium channels

What type of feedback is depolarisation an example of?

• Negative feedback

• Positive feedback

• Neutral feedback

• No feedback

What is the role of voltage-gated channel proteins?

• To allow glucose to pass through the membrane

• To allow sodium and potassium ions to pass through the membrane

• To allow water to pass through the membrane

• To allow proteins to pass through the membrane