Place the following events of the action potential in the correct order. 1) Voltage-gated Na+ channels open, and Na+ flows in
2) Voltage-gated K+ channels close, membrane potential returns to rest
3) Membrane is depolarized to threshold
4) Voltage-gated Na⁺ channels close
5) Voltage-gated K⁺ channels open, membrane rapidly repolarizes
6) Membrane rapidly depolarizes

Question

Quizplus · Accepted Answer

The action potential sequence starts with membrane depolarization to threshold (step 3). This causes voltage-gated Na+ channels to open, so Na+ flows into the cell (step 1), which rapidly depolarizes the membrane (step 6). Once the membrane reaches its peak depolarization, the voltage-gated Na+ channels close (step 4) and voltage-gated K+ channels open (step 5), allowing K+ to flow out of the cell, causing rapid repolarization. Finally, the K+ channels close (step 2), and the membrane returns to its resting state. Therefore, the correct order is 3, 1, 6, 4, 5, 2. The only option that matches this order is B.

Place the Following Events of the Action Potential in the Correct