Final answer:
Proteins have various functions including enzyme activity, transport, structure, gene regulation, and defense. The CFTR protein in cystic fibrosis is responsible for chloride ion transport.
Step-by-step explanation:
Proteins have a variety of functions in the body. They act as enzymes to catalyze chemical reactions, transport molecules and ions across cell membranes, provide structural support, regulate gene expression, and act as antibodies to defend against pathogens.
The CFTR protein, which is implicated in the genetic disorder cystic fibrosis (CF), is responsible for transporting chloride (Cl-) ions out of the cell. In individuals with CF, a mutation in the CFTR gene leads to the production of a defective CFTR protein that is not properly incorporated into the cell membrane, resulting in impaired ion transport