Cholesterol is a starting material for vitamin D and bile acids.

• A. Vitamin D and bile acids
• B. Cholesterol
• C. Glucose
• D. Amino acids

Answer: (D)

Cholesterol acts as a foundational precursor for several important biomolecules. Vitamin D and bile acids are both derived from cholesterol. In the skin, UV light converts a cholesterol derivative to vitamin D3, which is then processed in the liver and kidneys to the active hormone form. In the liver, cholesterol is transformed by specific enzymes into primary bile acids, which are later conjugated to form bile salts that aid fat digestion. Because cholesterol is the starting point for these two compounds, the statement is true. Glucose and amino acids come from separate metabolic pathways and are not produced directly from cholesterol.