Question

question 11 (1 point)
what is the main function of the sodium - potassium pump?
○ to produce atp for the cell
○ to move sodium (na+) and potassium (k+) ions across the cell membrane against their concentration gradients
○ to allow sodium (na+) and potassium (k+) ions to move down their concentration gradients by diffusion
○ all of the above.

Explanation:

1. Analyze Option 1: The sodium - potassium pump uses ATP (it is an ATP - consuming pump), not produce ATP. So this option is incorrect.
2. Analyze Option 2: The sodium - potassium pump is an active transport mechanism. It moves 3 $Na^+$ ions out of the cell and 2 $K^+$ ions into the cell, both against their concentration gradients (from low to high concentration), which requires energy (in the form of ATP). This matches the function of the sodium - potassium pump.
3. Analyze Option 3: Movement down the concentration gradient by diffusion is passive transport. The sodium - potassium pump is active transport, so this option is incorrect.
4. Analyze Option 4: Since Options 1 and 3 are incorrect, "All of the above" is also incorrect.

Answer:

B. To move sodium (Na+) and potassium (K+) ions across the cell membrane against their concentration gradients