Question

what prevents the na⁺ and k⁺ gradients from dissipating?
na⁺ cotransporter
na⁺-k⁺ atpase
na⁺ and k⁺ leaks
h⁺-k⁺ atpase

Explanation:

The \(Na^{+}-K^{+}\) ATPase (also known as the sodium - potassium pump) is an active transport mechanism. It uses the energy from ATP hydrolysis (\(ATP
ightarrow ADP + Pi\)) to move \(Na^{+}\) out of the cell (against its concentration gradient) and \(K^{+}\) into the cell (against its concentration gradient). This counter - acts the natural tendency of ions to move down their concentration gradients (which would dissipate the gradients). The \(Na^{+}\) cotransporter is involved in the coupled transport of \(Na^{+}\) with other molecules (not directly in maintaining \(Na^{+}-K^{+}\) gradients). \(Na^{+}\) and \(K^{+}\) leaks would contribute to gradient dissipation (not prevent it). The \(H^{+}-K^{+}\) ATPase is mainly involved in processes like acid secretion in the stomach (not in maintaining \(Na^{+}-K^{+}\) gradients).

Answer:

\(Na^{+}-K^{+}\) ATPase