Question

1. describe how a faulty protein alters the movement of chloride ions across the cell membrane. how does this change in the cell membrane lead to the symptoms of cystic fibrosis?

Explanation:

In cystic fibrosis, the CFTR (cystic fibrosis transmembrane conductance regulator) protein is faulty. This protein is responsible for the transport of chloride ions across the cell membrane. Normally, it allows chloride ions to move out of cells. When it's faulty, chloride ion movement is impaired. This leads to an imbalance in ion concentrations. As a result, water movement (osmosis) is affected. Less water moves out of cells (since water follows chloride ions in osmosis). This causes the mucus (which is related to these cells, like in the lungs and digestive tract) to become thick and sticky. Thick mucus in the lungs traps bacteria (leading to infections) and makes breathing difficult. In the digestive tract, it can block ducts (like pancreatic ducts), preventing enzymes from reaching the small intestine and causing digestive problems.

Answer:

A faulty protein (CFTR) impairs chloride ion movement out of cells. This reduces water movement (by osmosis) out of cells (as water follows chloride ions). Thick, sticky mucus forms (e.g., in lungs and digestive tract). In lungs: traps bacteria (infections), breathing issues. In digestive tract: blocks ducts (e.g., pancreatic), digestive problems.