Question

In cystic fibrosis there is?

• A. Failure of chloride ion transport
• B. Mucus clogging of lungs
• C. Defective functioning
• D. All the above

Answer 1

The correct option is D All the above

CF is caused by a mutation in the gene cystic fibrosis transmembrane conductance regulator (CFTR). The product of this gene (the CFTR protein) is a chloride ion channel important in creating sweat, digestive juices, and mucus. Mutations in the CFTR gene can occur, and different mutations cause different defects in the CFTR protein. One such defect is mutated CFTR protein do not allow chloride, iodide, and thiocyanate to cross the membrane appropriately. CFTR protein is also anchored to the outer membrane of cells in the sweat glands, lungs and all other remaining exocrine glands in the body. The CFTR protein is a channel protein that controls the flow of H2O and Cl- ions in and out of cells inside the lungs. When the CFTR protein is working correctly, ions freely flow in and out of the cells. However, when the CFTR protein is malfunctioning, these ions cannot flow out of the cell due to a blocked channel. This causes cystic fibrosis, characterized by the buildup of thick mucus in the lungs.

So, the correct answer is 'All the above'.