FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam 2025 - Free NABP Practice Questions and Study Guide

The CFTR protein, short for Cystic Fibrosis Transmembrane Conductance Regulator, plays a crucial role in transporting chloride and sodium ions across epithelial cells. This ion transport is essential for maintaining the balance of salt and water on epithelial surfaces, particularly in the lungs, pancreas, and intestines. In individuals with cystic fibrosis, mutations in the CFTR gene lead to defective CFTR protein, which impairs chloride ion transport. As a result, this disruption causes thick, viscous mucus to accumulate in various organs, particularly the lungs, leading to breathing difficulties and increased susceptibility to infections.

The other choices do not accurately represent the primary function of the CFTR protein. Insulin production is primarily regulated by pancreatic function, not directly influenced by CFTR. Gas exchange occurs in the alveoli of the lungs and is not a direct function of the CFTR protein. While mucus management is critical in cystic fibrosis, the CFTR protein does not break down mucus; instead, it affects the properties of the mucus by regulating ion transport and hydration. Therefore, the correct understanding of the CFTR protein's role centers around its function in ion transport, thereby affirming choice C as the accurate answer.