Question

How does the sodium-potassium pump contribute to the net negative charge of the interior of the cell?

a) By actively transporting sodium ions out of the cell.
b) By actively transporting potassium ions into the cell.
c) By exchanging sodium and potassium ions against their concentration gradients.
d) By allowing passive diffusion of ions across the cell membrane.

Answer 1

The sodium-potassium pump contributes to a cell's net negative charge by moving three Na+ ions out while only transporting two K+ ions in, resulting in a net loss of positive charge inside the cell.

Step-by-step explanation:

The sodium-potassium pump is key to maintaining the net negative charge inside the cells. This pump works by actively transporting three sodium (Na+) ions out of the cell while bringing two potassium (K+) ions in. This exchange results in a net loss of positive charge inside the cell since more cations are expelled than taken in, contributing to the interior of the cell being more negative than the exterior. Moreover, the fact that the pump moves ions against their concentration gradients makes this an example of active transport, which requires ATP to function.