The Standard Free Energy That Is Required for the Sodium-Potassium

Multiple Choice

The standard free energy that is required for the sodium-potassium ATPase to pump two K+ ions into the cell and three Na+ ions is +43.8 kJ/mol but the standard free energy change of hydrolysis of ATP is only -32 kJ/mol. This apparent imbalance of free energy can be accounted for because:

A) the movement of Na+ ions is down the concentration gradient.
B) the movement of K+ ions is down the concentration gradient.
C) the membrane potential favours the flow of ions.
D) more than one ATP is hydrolyzed.
E) the free energy provided from the hydrolysis of one ATP is sufficient under physiological conditions.