Question

During an action potential: you would expect ________ during resting potential, and ________ during repolarization.

a. Open K+ leak channels, open K+ channels
b. Open voltage-gated Na+ channels, closed Na+ leak channels
c. Open K+ leak channels, open voltage-gated Na+ channels
d. Negative membrane potential, trend toward positive potential

Answer 1

During the resting potential phase of the action potential, open K+ leak channels are expected, and during repolarization, open K+ channels are necessary to return the cell to its resting negative membrane potential. Therefore, the correct option is A.

Step-by-step explanation:

During an action potential, the correct sequence of events would be as follows: during the resting potential, you would expect open K+ leak channels as these help maintain the membrane at rest. Additionally, there are also closed voltage-gated Na+ channels. This means that the correct answer is a. Open K+ leak channels, open K+ channels. However, during repolarization, after the cell has reached the threshold and depolarized, voltage-gated Na+ channels will get inactivated and no more Na+ can enter the cell. Subsequently, during repolarization, voltage-gated K+ channels open to allow K+ to leave the cell, helping restore the negative membrane potential by a process called repolarization. Thus, during repolarization, the cell membrane potential trends back toward the negative resting potential.