Question

If ATP was unavailable to the cell, as would be the case when treated with an uncoupler of oxidative phosphorylation, the effects would be numerous. Among them, $N{a}^{+}/K^{+}$ ATPase function would be inhibited.
What would be a consequence of such an inhibitory action?

• A. Inhibiting the $N{a}^{+}/K^{+}$ pump would cause a cessation of all ion movement.
• B. Sodium would leak into the cell and potassium would leak out of the cell, down their electrochemical gradient.
• C. The ion concentration in the cell would "drift" towards that of the intercellular fluid.
• D. Water would flow out of the cell leading to crenation.

Answer 1

The correct option is B Sodium would leak into the cell and potassium would leak out of the cell, down their electrochemical gradient.

Na${}^{+}$/K${}^{+}$ ATPase, is a cationic pump that transports 3Na${}^{+}$ ions to the outside, while importing 2K${}^{+}$ against their concentration gradient. This maintains the inner membrane potential negative, In inhibition of the pump, the ions will move along their concentration gradient, reaching towards equilibrium through the leak channels that allow passive movement of these ions.

So, the correct answer is 'Sodium would leak into the cell and potassium would leak out of the cell, down their electrochemical gradient'