Question

multiple choice question
to create a gradient of na⁺ and k⁺ across the membrane of an animal cell, the energy in atp is ______ used

○ rarely
○ indirectly
○ directly

Explanation:

The Na⁺/K⁺ pump (sodium - potassium pump) in animal cell membranes directly uses ATP hydrolysis to transport 3 Na⁺ out of the cell and 2 K⁺ into the cell, creating the ion gradients. "Rarely" is incorrect as the pump actively uses ATP. "Indirectly" is wrong because the energy from ATP is used directly by the pump for the transport process.

Answer:

C. directly