Which class of lipids includes a backbone derived from an amino alcohol and often participates in cell recognition?

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

Answer: (B)

Backbone matters in lipid classification: sphingolipids are built on a backbone derived from an amino alcohol called sphingosine rather than glycerol. This structural choice enables many sphingolipids to have carbohydrate or phosphate-containing head groups that sit on the cell surface and participate in cell recognition and signaling. Glycosphingolipids, in particular, carry sugars that help cells recognize each other and interact with the environment. Other lipid classes use different backbones: waxes are esters of long-chain alcohols and fatty acids; phospholipids have a glycerol backbone with a phosphate head group; triglycerides are glycerol with three fatty acids for energy storage. Therefore, the lipid class described is sphingolipids.