Question

multiple select question
select all that apply
which of the following describes the sodium - potassium pump?

• it moves sodium ions and potassium ions across the membrane in opposite directions.
• it is an active transport mechanism.
• it does not require atp to function.
• it transports both sodium ions and potassium ions down their respective concentration gradients.

Explanation:

1. For the option "It moves sodium ions and potassium ions across the membrane in opposite directions": The sodium - potassium pump moves 3 sodium ions out of the cell and 2 potassium ions into the cell, so they move in opposite directions. This statement is correct.
2. For the option "It is an active transport mechanism": Active transport requires energy (ATP) and moves substances against their concentration gradients. The sodium - potassium pump uses ATP and moves ions against their gradients, so it is an active transport mechanism. This statement is correct.
3. For the option "It does not require ATP to function": The sodium - potassium pump hydrolyzes ATP to get energy for its function. So this statement is incorrect.
4. For the option "It transports both sodium ions and potassium ions down their respective concentration gradients": The sodium - potassium pump moves sodium ions out of the cell (against the sodium concentration gradient, as sodium is more concentrated outside) and potassium ions into the cell (against the potassium concentration gradient, as potassium is more concentrated inside). So this statement is incorrect.

Answer:

A. It moves sodium ions and potassium ions across the membrane in opposite directions
B. It is an active transport mechanism