Final answer:
People with Cystic Fibrosis have a dysfunctional CFTR ion channel, which leads to the accumulation of thick and sticky mucus in the respiratory system.
Step-by-step explanation:
People with Cystic Fibrosis have a dysfunctional CFTR ion channel. The CFTR protein is responsible for transporting Cl- ions out of the cell in healthy individuals. However, in individuals with Cystic Fibrosis, the gene for CFTR is mutated, resulting in the production of a defective channel protein that is not incorporated into the cell membrane. As a result, Cl- ions are not transported out of the cell in adequate numbers, leading to the accumulation of thick and sticky mucus in the respiratory system.