Which class of lipids is made up of rigid carbon rings with no fatty acid tails?

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

Answer: (A)

Verified step by step guidance

1. Understand the structure of each lipid class mentioned in the problem: Steroids, Waxes, Phospholipids, and Triglycerides.
2. Recall that steroids are characterized by a structure consisting of four fused carbon rings, making them rigid and distinct from other lipid classes.
3. Note that waxes are composed of long-chain fatty acids esterified to long-chain alcohols, which include fatty acid tails.
4. Phospholipids consist of a glycerol backbone, two fatty acid tails, and a phosphate group, making them structurally different from steroids.
5. Triglycerides are composed of a glycerol backbone bonded to three fatty acid tails, which also differentiates them from steroids.