Question

In Glycolipids and sphingolipids, glycerol is replaced by which amino alcohol?

• A. Sphingomyelins
• B. Gangliosides
• C. Sphingosine
• D. Sulfatides

Hint:

The name of the class of lipids often gives a clue to its structure. Just as \textbf{glycero}lipids have a \textbf{glycerol} backbone, \textbf{sphingo}lipids have a \textbf{sphingosine} backbone. The other options are examples of complex sphingolipids, not the fundamental building block.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Biological membranes are primarily composed of lipids. There are two main classes of membrane lipids based on their backbone structure: glycerophospholipids (which use a glycerol backbone) and sphingolipids. The question asks for the specific molecule that forms the backbone of sphingolipids, replacing the glycerol molecule.

Step 2: Detailed Explanation:
- Sphingosine is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms the characteristic backbone of sphingolipids.
- A sphingolipid is formed when a fatty acid is joined to the sphingosine via an amide linkage, forming a ceramide. Various head groups can then be attached to the ceramide.
- The other options provided are all types of complex sphingolipids, not the backbone molecule itself:
- Sphingomyelins are ceramides with a phosphocholine or phosphoethanolamine head group.
- Gangliosides and Sulfatides are types of glycolipids (specifically glycosphingolipids), where the head group is a complex oligosaccharide.

Step 3: Final Answer:
In sphingolipids, the glycerol backbone found in glycerophospholipids is replaced by the amino alcohol sphingosine. Therefore, option (C) is the correct answer.