Q.Describe the types of lipids and mention their biological significance.

Step 1. Simple lipids are esters of fatty acids with an alcohol. Fats (esters with glycerol, e.g. triglycerides) are a high-calorific-value energy reserve, stored in seeds (plants) or adipose tissue (animals), and provide insulation and mechanical cushioning. Waxes (esters with long-chain alcohols) form a water-repellent protective coating on skin/hair in animals and on stems/leaves/fruits in plants.

Step 2. Compound lipids carry an extra group besides the fatty-acid-alcohol ester. Phospholipids (glycerol + 2 fatty acids + phosphate) form the cell membrane's lipid bilayer because of their polar-head/non-polar-tail structure. Glycolipids (glycerol + fatty acids + sugar) are especially significant in nerve tissue, being abundant in brain white matter and the myelin sheath. …

Describe each of the three lipid classes (simple, compound, derived) and state the specific …

• Describing only fats and forgetting waxes, phospholipids, glycolipids and sterols, each of which the chapter treats as distinct types with distinct significance. …