Final answer:
The false statement about CFTR protein is that it causes cystic fibrosis. While CFTR gene mutations cause the condition, the CFTR protein itself regulates chloride ion transport and, when functional, does not cause disease. It is implicated in mucus viscosity and conducts bicarbonate ions as well.
Step-by-step explanation:
The statement that is FALSE regarding the CFTR protein is 'a. it causes cystic fibrosis.' While mutations in the CFTR gene are responsible for causing cystic fibrosis, the protein itself, when functioning correctly, does not cause the disease. The CFTR protein is found on epithelial cells (b) and acts as a cyclic AMP-regulated chloride channel (c). Its proper function is indeed important in establishing the viscosity of mucus (d) because it regulates chloride ion transport, thereby affecting the water content and viscosity of the mucus. Additionally, it is known to conduct bicarbonate ions (e), which helps in maintaining the pH balance and proper function of the mucus.
CFTR is an integral membrane protein that transports Cl- ions out of cells. In a person with cystic fibrosis, a mutation in the CFTR gene leads to the production of a defective protein that cannot be properly incorporated into the cell membrane and is often degraded. The absence of functional CFTR creates issues with ion transportation, which then prevents normal water movement and creates thick, sticky mucus that clogs passageways, leading to frequent infections and complications within the respiratory system.
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