Which backbone is found in phospholipids?

Which backbone is found in phospholipids?

• A. Glycerol backbone
• B. Fructose backbone
• C. Ribose backbone
• D. Deoxyribose backbone

Answer: (A)

Phospholipids are built on a glycerol backbone, a three-carbon molecule that acts as the scaffold. Two fatty acid tails attach to the first two carbons, forming the hydrophobic region, while a phosphate-containing head group attaches to the third carbon, creating the hydrophilic region. This arrangement makes phospholipids amphipathic and essential for forming cell membranes. Sugars like fructose, ribose, and deoxyribose are carbohydrates (and, in the case of ribose and deoxyribose, components of RNA and DNA), not lipid backbones. They don’t serve as the scaffold that links fatty acids to a membrane-building lipid, which is why glycerol is the correct backbone here.

Phospholipids are built on a glycerol backbone, a three-carbon molecule that acts as the scaffold. Two fatty acid tails attach to the first two carbons, forming the hydrophobic region, while a phosphate-containing head group attaches to the third carbon, creating the hydrophilic region. This arrangement makes phospholipids amphipathic and essential for forming cell membranes.

Sugars like fructose, ribose, and deoxyribose are carbohydrates (and, in the case of ribose and deoxyribose, components of RNA and DNA), not lipid backbones. They don’t serve as the scaffold that links fatty acids to a membrane-building lipid, which is why glycerol is the correct backbone here.