Chapter 3, Problem 1DID

Organelles and Cystic Fibrosis

A plasma membrane transport protein called CFTR moves chloride ions out of cells lining cavities and ducts of the lungs, liver, pancreas, intestines, and reproductive system. Water that follows the ions creates a thin film that allows mucus to slide easily through these structures.

People with cystic fibrosis (CF) have too few copies of the CFTR protein in the plasma membranes of their cells. Not enough chloride ions leave the cells, and so not enough water leaves them either. The result is thick, dry mucus that clogs the airways to the lungs and other passages. Symptoms include difficulty breathing and chronic lung infections. In 2000, researchers tracked the cellular location of the CFTR protein as it was being produced in cells from people with CF (Figure 3.13).

Figure 3.13 Cellular location of the CFTR protein.

Graph compares the amounts of CFTR protein found in endoplasmic reticulum, vesicles travel in g from ER to Golgi, and Golgi bodies in CF cells and normal cells.

Which organelle contains the least amount of CFTR protein in normal cells? In CF cells?