question_answer

\[N{{a}^{+}}-{{K}^{+}}\]pump is found in the membranes of many cells, like nerve cells. It works against electrochemical gradient and involve an integral protein ATPase. For each molecule of ATP used

A)  3 ions of\[N{{a}^{+}}\]are pumped out and\[2{{K}^{+}}\]are taken in

B)  3 ions of\[N{{a}^{+}}\]are taken in and\[2{{K}^{+}}\]are pumped out.

C)  2 ions of\[N{{a}^{+}}\]are thrown out and\[3{{K}^{+}}\]are absorbed

D)  3 ions of\[{{K}^{+}}\]are absorbed and\[3N{{a}^{+}}\]are pumped out

Correct Answer: A

Solution :

 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-protassium exchange pump of the cell.