ATPase is which type of pump?
a) Secondary active
b) Electrogenic
c) Symport
d) All of the above
Correct Answer - B
Ans. B. Electrogenic
[Ref Ganong 24th/e p.51, 10; Guyton 12th/e p.53]
Sodium-potassium pump:
- Most important pump for primary active transport in body.
- An Electrogenic pump.
- Responsible for maintaining Na+ & K+ conc. difference across cell
membrane.
Mechanism: - ICF - High K+ concentration.
- ECF - High Na+ concentration.
- Both Na+ & K+ transported against concentration gradient.
- Uses energy by hydrolyzing ATP;
Functions: - Pump contains ATPase activity.
- Na±K+ pump extrudes -
- 3 Na+ out from cell.
- Pumps 2 K+ into cell.
- Coupling ratio of Na±K+pump - 3:2