Multiple choice Molecular and cellular defect of cystic fibrosis is the defective chloride channel in epithelial cells leading to excessive mucus in the lungs defective chloride channel in the epithelial cells leading to no mucus in the lungs defective sodium channel in the epithelial cells leading to excessive mucus in the lungs defective sodium channel in the epithelial cells leading to no mucus in the lungs none of the above Reveal answer Fill a bubble to check yourself A Correct answer Explanation Defective chloride channel in epithelial cells leads to excessive mucus in lungs