Two electrodes, one on either side of the cell membrane of a resting neuron, show a difference of about ‒65 mV.If the value changes quickly to about +50 mV and then rapidly returns to ‒65 mV, the most likely explanation is that A) the cell membrane briefly became hyperpolarized. B) a graded potential passed by the electrodes. C) an action potential was triggered by changes in voltage-gated Na⁺ and K⁺ channels. D) voltage-gated Na⁺ channels closed, causing a spike of depolarization, and then opened again. E) leak K⁺ channels opened and then closed.

Question

Quizplus · Accepted Answer

The rapid change in voltage from ‒65 mV to +50 mV and then back to ‒65 mV is characteristic of an action potential. This is triggered by changes in voltage-gated ion channels, specifically Na+ and K+ channels, which open and close to allow the flow of ions across the cell membrane, leading to depolarization and repolarization.

Two Electrodes, One on Either Side of the Cell Membrane