Final answer:
70% of point mutations associated with cystic fibrosis affect the primary structure of the CFTR protein, disrupting its ability to transport Cl- ions and leading to characteristic symptoms of the disease.
Step-by-step explanation:
70% of point mutations that cause cystic fibrosis disrupt the primary structure of the CFTR protein, resulting in defective Chloride ion transport. These mutations can affect the conformation of the protein, preventing it from performing its role in active transport, where ATP enables the CFTR to transport Cl- ions out of the cell.
In cystic fibrosis, the CFTR protein, which normally functions to help move salt and water in and out of cells, is compromised by genetic mutations. The most common mutation involves the deletion of a phenylalanine amino acid. This seemingly small change can significantly alter the protein's primary structure and ultimately lead to the malfunction of the transmembrane chloride channel. Affected individuals experience thick and sticky mucus buildup, particularly in the lungs and digestive system, due to impaired ion transport, which is a hallmark of cystic fibrosis pathology.