If the CFTR doesn\'t work correctly due to a mutation, Cl^- movement is blocked and an abnormally thick sticky mucus is produced on the outside of the cell. This mucus clogs the airways in the lungs, and increases the risk of infection by bacteria. Figure 2 illustrates a mutant CFTR channel in the epithelial cells lining the lung. Suppose the Na^+ channel in the figure was open. Why would more Na^+ enter a cell with mutant CFTR than a cell with normal CFTR? How is solute composition of the mucus layer (outside of cell) affected by mutant CFTR? What membrane protein not shown in this diagram would be important for maintaining ion homeostasis, and why is it important? Solution .....Suppose the Na+ channel in the figure was open, why would more Na enter the cell with mutant CFTR.....