Cystic fibrosis is a genetic disease in humans in which the CFTR protein, which functions as a chloride ion channel, is missing or nonfunctional in cell membranes.
-If the sodium ion concentration outside the cell increases, and the CFTR channel is open, in what direction will chloride ions and water move across the cell membrane?
A) Chloride ions will move out of the cell, and water will move into the cell.
B) Both chloride ions and water will move out of the cell.
C) Chloride ions will move into the cell, and water will move out of the cell.
D) Both chloride ions and water will move into the cell.
E) The movement of chloride ions and water molecules will not be affected by changes in sodium ion concentration outside the cell.

Question

Quizplus · Accepted Answer

When the sodium ion concentration outside the cell increases and the CFTR channel is open, chloride ions will move out of the cell to balance the ion concentration. Water will follow the chloride ions out of the cell due to osmosis, leading to both chloride ions and water moving out of the cell.

Cystic Fibrosis Is a Genetic Disease in Humans in Which