Question

Which of the following events requires active transport in an intestinal epithelial cell?

a.) uptake of glucose
b.) export of glucose
c.) uptake of Na+
d.) export of Na+
e.) none of the above

Answer 1

The export of Na+ from intestinal epithelial cells requires active transport, powered by the Na+/K+ ATPase pump which actively moves Na+ out of the cell to maintain an electrochemical gradient.

Step-by-step explanation:

The event that requires active transport in an intestinal epithelial cell is the export of Na+. During the process of glucose absorption, sodium ions (Na+) are taken up into the cell from the lumen of the intestine by a mechanism called secondary active transport, which involves a symport protein that simultaneously transports Na+ and glucose into the cell. This transport is powered by the Na+/K+ ATPase pump located at the basal surface of the cell, which actively exports Na+ in exchange for K+ while hydrolyzing ATP to ADP. This active transport of Na+ out of the cell is essential to maintain the electrochemical gradient necessary for glucose and Na+ to move into the cell from the lumen, against the concentration gradient of glucose.