Question

Which one of the following is the correct sequence of events that shows the sequence of events of a nerve impulse?

1. The membrane becomes depolarized.

2. Sodium channels open and sodium ions diffuse inward.

3. The membrane becomes repolarized.

4. Potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell.

a. 1, 2, 4, 3.

b. 3, 2, 4, 1.

c. 2, 1, 4, 3.

d. 2, 1, 3, 4.

e. 4, 1, 3, 2.

Answer 1

The correct answer is option c. The correct sequence of events for a nerve impulse is sodium channel opening, membrane depolarization, potassium channel opening coupled with sodium transport, and repolarization, which corresponds to option c. 2, 1, 4, 3.

Step-by-step explanation:

The correct sequence of events that shows the sequence of events of a nerve impulse is starting with sodium channels opening and sodium ions diffusing inward, which leads to the depolarization of the membrane. Once the depolarization threshold is reached, the process leads to the opening of potassium channels, and potassium ions diffuse outward, while sodium is actively transported out of the cell, initiating repolarization. After repolarization, the membrane returns to its resting state.

Based on the information provided, the correct sequence is: Sodium channels open and sodium ions diffuse inward (2), the membrane becomes depolarized (1), potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell (4), and finally, the membrane becomes repolarized (3). Thus, the correct option is c. 2, 1, 4, 3.