#Question id: 12180

Following statements are regarding to cotransport.

A. The two forces constituting the electrochemical gradient—the membrane electric potential and the ion concentration gradient—may act in the same or opposite directions.

B. Cotransporters use the energy released by movement of an ion (usually H+ or Na+) down its electrochemical gradient to power the import or export of a small molecule or different ion against its concentration gradient.

C. Cotransporters use the energy released by movement of an ion (usually H+ or Na+) down its electrochemical gradient to power the import or export of a small molecule or different ion down its concentration gradient.

D. The cells lining the small intestine and kidney tubules contain symporters that couple the energetically favorable entry of Na+ to the import of glucose against its concentration gradient.

Which of the following is incorrect?