Question

All of the following must occur before a second action potential can begin, EXCEPT

A. the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments.

B. the Na+ inactivation gate must open and the Na+ activation gate must close.

C. the absolute refractory period must occur.

D. the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments; the Na+ inactivation gate must open; and the Na+ activation gate must close.

E. None of the answers are correct.

Answer 1

All of the listed options are correct and must occur before a second action potential can begin.

Step-by-step explanation:

The correct answer is E. None of the answers are correct. All of the options listed are actually correct and must occur before a second action potential can begin. The movement of Na+ and K+ ions back to their original compartments is necessary for repolarization and the restoration of the resting membrane potential. The opening of the Na+ inactivation gate and the closing of the Na+ activation gate are essential steps in the inactivation of the voltage-gated Na+ channel. The absolute refractory period is a period of time during which another action potential cannot be initiated. Therefore, all of the given options are necessary for the initiation of a second action potential.