Which lipids assist in absorbing fat-soluble vitamins and are components of cell membranes, nerve cells, and certain hormones?

• A. Carbohydrates
• B. Fats
• C. Proteins
• D. Minerals

Answer: (B)

Lipids are the molecules that do both nourishment and structure in the body. Fats, a major type of lipid, are involved in absorbing fat-soluble vitamins A, D, E, and K because these vitamins dissolve in fats and rely on dietary fats to form micelles with bile salts for transport to the intestinal lining. Beyond digestion, lipids form the backbone of cell membranes through phospholipids and cholesterol, which shape membrane structure and fluidity. They also make up myelin in nerve cells, insulate and protect neurons, and serve as precursors to steroid hormones derived from cholesterol. Because these roles—facilitating fat-soluble vitamin absorption, composing membranes, supporting nerve cell function, and yielding certain hormones—are all tied to fats, this choice best fits the description. Carbohydrates, proteins, and minerals don’t perform these lipid-specific structural and transport roles.