Question

Sodium is more concentrated outside the cell than inside, despite the fact that some sodium does diffuse into the cell. The reason for this is:

A) Active transport of sodium out of the cell
B) Passive diffusion of sodium into the cell
C) The cell membrane is impermeable to sodium
D) Sodium is actively transported into the cell

Answer 1

Sodium is more concentrated outside the cell due to the active transport of sodium out of the cell by the sodium-potassium pump.

Step-by-step explanation:

In the resting state, sodium (Na*) is at higher concentrations outside the cell, so it will tend to move into the cell.

Potassium (K*), on the other hand, is more concentrated inside the cell, and will tend to move out of the cell.

This is due to the active transport of sodium out of the cell by the sodium-potassium pump.