What are the components of a triglyceride?

• A. They consist of glycerol and three fatty acids
• B. They are built from glucose and fatty acids
• C. They consist of a cholesterol backbone with fatty acids
• D. They consist of amino acids linked to glycerol

Answer: (A)

Triglycerides are neutral lipids built from a glycerol backbone with three fatty acids esterified to each of the three hydroxyl groups. Each fatty acid is attached by an ester bond, formed through a dehydration synthesis reaction. This combination—glycerol plus three fatty acids—creates the triacylglycerol structure that serves as the main energy storage form in adipose tissue. The fatty acid chains can vary in length and saturation, which affects properties like how much energy they store and their melting behavior.

This differs from other possibilities: glucose plus fatty acids would describe a sugar-fat assembly rather than a true triglyceride; a cholesterol backbone with fatty acids would describe cholesterol esters or other sterol-derived lipids; and amino acids linked to glycerol would not form a triglyceride at all. The glycerol-and-three-fatty-acid arrangement is the defining components of a triglyceride.