The bacterium Vibrio cholerae releases a toxin that blocks a channel protein in the membranes of cells that line the intestine. This toxin prevents the movement of sodium ions from the inside of the intestine into cells. If the sodium ions could not move into the cells, how would this affect the movement of water between the inside of the intestine and the cells?
A) Water would leave the intestines and enter the cells by osmosis.
B) Water would leave the intestines and enter the cells by facilitated diffusion.
C) Water would leave the cells and enter the intestines by facilitated diffusion.
D) The movement of water would not be affected.
E) Water would leave the cells and enter the intestines by osmosis.

Question

Quizplus · Accepted Answer

Water movement across cell membranes is often driven by osmosis, which is the diffusion of water from areas of low solute concentration to areas of high solute concentration. If sodium ions cannot move into the cells, the solute concentration inside the intestine would be higher than inside the cells, leading to water moving out of the cells and into the intestine by osmosis to balance the concentration difference.

The Bacterium Vibrio Cholerae Releases a Toxin That Blocks a Channel