1. Lipids act as important storage compounds. 

2. They form membranous structures of the cell.

3. Lipids are rich source of energy and the energy produced by 1 gram of fat is more than twice than that produced from 1 gram of glucose.

4. They serve as main parts of cell wall in plants and form exoskeleton of insects.

5. In certain animals such as whale, polar bear etc. they form an insulating layer.

6. They are also used in the synthesis of steroid hormones and bile salts.

7. Fats from cushion like structures below vital organs such as brain, heart, kidneys, eyes etc. and protect them from mechanical shocks.

8. Fats insulate the nerve fibres electrically.