Question

which best describes the sodium-potassium pump? * a) moves sodium in, potassium out b) moves sodium out, potassium in c) moves both sodium and potassium in d) moves both sodium and potassium out

Explanation:

The sodium - potassium pump is an active transport mechanism in cell membranes. It uses energy (ATP) to move 3 sodium ions ($\text{Na}^+$) out of the cell and 2 potassium ions ($\text{K}^+$) into the cell. This helps in maintaining the electrochemical gradient across the cell membrane, which is essential for functions like nerve impulse transmission and muscle contraction. So option B correctly describes the sodium - potassium pump.

Answer:

B) Moves sodium out, potassium in