Question

$N{a}^{+}-K^{+}$pump is found in membranes of many cells, like nerve cells. It works against electro chemical gradient and involve an integral protein ATPase. For each molecule of ATP used:

• A. 3 ions of $N{a}^{+}$are pumped out and two $K^{+}$ are taken in
• B. 3 ions of $N{a}^{+}$are taken in and $2K^{+}$are pumped out
• C. 2 ions of $N{a}^{+}$are thrown out and $3K^{+}$are absorbed
• D. 3 ions of $K^{+}$are absorbed and $3N{a}^{+}$are pumped out

Answer 1

Answer: (A)

Energy from ATP cause confermational change in the solute carrier complex. From energy of one ATP, $3N{a}^{+}$pumped outside and two $K^{+}$ taken in. This process of expelling out $N{a}^{+}$ions and drawing in $K^{+}$ions against the concentration gradient and electrochemical gradient is called sodium-potassium exchange pump of the cell.

This pump operates by inovlving the $N{a}^{+}-K^{+}$-ATPase enzyme located in the cell membrane. Such electrogenic pump develops positive charge outside the membrane and a negative charge to cell's interior. This difference in charge on either side of the membrane of a resting neuron is the resting membrane potential.