Question

The Na⁺/K⁺ pump actively moves?

1) 2Na⁺ in, 3 K⁺ out.
2) 2Na⁺ out, 3 K⁺ in.
3) 3 Na⁺ in 2 K⁺ out.
4) 3 Na⁺ out, 2 K⁺ in.
5) 1 Na⁺ out, 1 K⁺ in.

Answer 1

The sodium-potassium pump moves 3 sodium ions out of the cell and 2 potassium ions into the cell, establishing an essential electrochemical gradient and contributing to the cell's resting membrane potential.

Step-by-step explanation:

The Na⁺/K⁺ pump, also known as the sodium-potassium pump, is critical in maintaining the electrochemical gradient across the cell membranes of animal cells. This active transport mechanism uses ATP to move ions against their concentration gradients. For each cycle of the pump, three sodium ions (Na⁺) are moved out of the cell, and two potassium ions (K⁺) are moved into the cell. This action not only regulates ion concentration within the cell but also contributes to the negative charge inside the cell, as the pump moves a net positive charge out of the cell. This process is vital for many cellular functions, including nerve impulse transmission and muscle contraction.

The correct answer to the student's question is 4) 3 Na⁺ out, 2 K⁺ in.