Triglycerides are a type of lipid formed from glycerol and how many fatty acids?

• A. Phospholipids
• B. Steroids
• C. Triglycerides
• D. Waxes

Answer: (C)

The key idea is how triglycerides are built. A triglyceride has a glycerol backbone with three fatty acid molecules attached, one to each hydroxyl group on glycerol. That exact arrangement—glycerol plus three fatty acids—defines this lipid as a triglyceride and is what makes it a major energy storage form, highly hydrophobic and energy-dense.

Phospholipids differ by having two fatty acids and a phosphate-containing head group, which gives them amphipathic properties and a primary role in membranes. Steroids aren’t built from glycerol and fatty acids at all—they have a four-ring hydrocarbon skeleton. Waxes are esters of fatty acids with long-chain alcohols, not glycerol with three fatty acids. So the description that matches glycerol with three fatty acids is triglycerides.