In intestinal epithelial cells, a transport protein moves the bulky, polar glucose molecules through the membrane into the cytoplasm, while simultaneously transporting Na + through the membrane into the cell down its electrochemical gradient. Which example correctly describes this cotransport of glucose and sodium?

a primary active transport by an antiporter

b. secondary active transport by a symporter

c. primary active transport by a symporter

d. secondary active transport by an antiporter

Question

Rosie

Biology

31 July, 18:44

In intestinal epithelial cells, a transport protein moves the bulky, polar glucose molecules through the membrane into the cytoplasm, while simultaneously transporting Na + through the membrane into the cell down its electrochemical gradient. Which example correctly describes this cotransport of glucose and sodium?

a primary active transport by an antiporter

b. secondary active transport by a symporter

c. primary active transport by a symporter

d. secondary active transport by an antiporter

+4

Answers (1)

Know the Answer?

Damian Hutchinson · Answer 1

b. secondary active transport by a symporter

Explanation:

Glucose is a monosaccharide, one of the digestion products of carbohydrates. Glucose is a polar molecule and can not diffuse through the hydrophobic core of the cell membrane of absorptive cells of the small intestine.

A symporter transports one glucose and two sodium ions from the cavity of the small intestine into the absorptive cells of the villi. Since both Na + and glucose are transported in the same direction, it is a symport. Here, the energy of the ionic concentration gradient of Na + serves as a source of energy for glucose transport, the process of glucose transport is secondary active transport.