Question

The movement of a number of molecules across the apical surface of the epithelial cell by secondary transporters is coupled to the ______- gradient that is maintained by the _____ on the basolateral surface of the epithelial cell.

a) Electrical; sodium-potassium pump.
b) Chemical; sodium-potassium pump.
c) Concentration; aquaporins.
d) Osmotic; potassium-sodium pump.

Answer 1

The movement across the epithelial cell's apical surface is coupled to the electrochemical gradient maintained by the sodium-potassium pump.

Step-by-step explanation:

The movement of a number of molecules across the apical surface of the epithelial cell by secondary transporters is coupled to the electrochemical gradient that is maintained by the sodium-potassium pump on the basolateral surface of the epithelial cell.

The correct answer is a) Electrical; sodium-potassium pump. Secondary active transport, such as the Na+/glucose symport mechanism, relies on the electrochemical gradient established by the sodium-potassium pump. This pump moves Na+ out of the epithelial cells, maintaining an electrochemical gradient for Na+ to move into the cells along with other substances like glucose against their concentration gradient from the tubular lumen.