Final answer:
Point mutations in the CFTR gene are responsible for cystic fibrosis, with many leading to misfolded proteins that are degraded and therefore nonfunctional, disrupting chloride ion transport across cell membranes.
Step-by-step explanation:
Cystic fibrosis (CF) is caused by mutations in the gene coding for the CFTR protein, which is essential for transporting chloride ions across cell membranes. Most of these mutations result in a protein that is misfolded and can't reach the cell membrane, hence becoming nonfunctional and degraded within the cell. This disrupts the ion balance, leading to the symptoms of CF. Point mutations in the CFTR gene can lead to a misfolded protein that fails to fold properly and is subsequently degraded. Some mutations, like the deletion of phenylalanine at position 508, are known to cause a disruption in the folding of the CFTR protein. Since CF is a genetic disorder, understanding genetics, especially autosomal recessive inheritance, is key to grappling with how CF is inherited and its implications. Carriers of the CF gene have one normal allele and one mutated allele, producing enough functional CFTR protein to avoid the symptoms of CF.