Questions: 4 1 point What is the reversal potential of an ion channel? The voltage at which ion flow through the channel changes direction The voltage at which an action potential is generated The voltage that triggers neurotransmitter release The resting membrane potential of a neuron

The answer is the first one: The voltage at which ion flow through the channel changes direction.

Explanation for each option:

1. The voltage at which ion flow through the channel changes direction: This is the correct definition of the reversal potential. It is the membrane potential at which there is no net flow of a particular ion through its channel, meaning the electrical and chemical gradients are balanced.

2. The voltage at which an action potential is generated: This is incorrect. The voltage at which an action potential is generated is known as the threshold potential, not the reversal potential.

3. The voltage that triggers neurotransmitter release: This is incorrect. Neurotransmitter release is typically triggered by the arrival of an action potential at the axon terminal, leading to calcium influx, not directly by the reversal potential.

4. The resting membrane potential of a neuron: This is incorrect. The resting membrane potential is the voltage across the neuronal membrane when the neuron is not actively sending a signal, and it is not the same as the reversal potential of an ion channel.

In summary, the reversal potential is specifically the voltage at which the direction of ion flow through a channel changes, balancing the electrical and chemical forces acting on the ion.