Cystic fibrosis is the most common lethal genetic disease in the United States. It strikes one out of every 2,500 people of European descent, though it is less common in other groups. Cystic fibrosis is the result of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Over 1,800 different mutations have been identified that can cause cystic fibrosis. People who inherit two recessive CFTR alleles have the disease. Why do certain mutations cause cystic fibrosis?

Answer and explanation:

Cystic fibrosis occurs due to mutations in the CFTR gene, causing deficient ion transport in patients through cell membranes with a reduction in the amount of water from bronchial secretion.

This decrease makes the secretion more adherent to the bronchial walls and compromises the cleaning of these channels, facilitating pulmonary infections.

The disease also causes the blockage of the pancreas ducts, reducing the arrival of digestive enzymes in the intestines.

For an individual to develop cystic fibrosis by mutations, it is necessary to have both chromosomes 7 with the mutated CFTR gene. This means that a person needs to inherit mutated chromosome 7 from his mother and father.

geologic time scale (for gradpoint) =)

the answer is c.

by: nicholas dooley