Question

In intestinal epithelial cells, a transport protein moves glucose into the cytoplasm against its concentration gradient at the same time that it transports Na+ into the cell down its electrochemical gradient. Which of the following CORRECTLY describes this cotransport of glucose and sodium?Primary active transport by an antiporter.Secondary active transport by a symporter.Primary active transport by a symporter.Secondary active transport by an antiporter.

Answer 1

Answer:

Secondary active transport by a symporter

Explanation:

Secondary active transport includes uphill transport of one substance against its concentration gradient coupled with downhill transport of another substrate. Glucose is transported against the concentration gradient into the cytoplasm and this active transport is driven by downhill transport of Na+ into the cells. This makes the transport of glucose a secondary active transport. Both glucose and Na+ are transported into the cell (in the same direction). Since both are moved simultaneously in the same direction, it is a symport.