1.Simple Lipids

They are esters of fatty acids with various alcohols. They are divided into two groups a. fat  and b. wax.

 a. Fats: They are esters of fatty acids with glycerol. They are also called triglyceride or neutral fat. A fat in the liquid state at room temperature is known as oil. Monoglycerides and diglycerides are also present in natural lipids.

b. Waxes: They are fatty acid esters of alcohols other than glycerol. The fatty acids present are long-chain acids. The alcohol may be aromatic or  aliphatic.

2.Compound lipids

Compound lipids are esters of fatty acids containing groups in addition to an alcohol and a fatty acid. 

a.Phospholipids: Lipids containing fatty acids, an alcohol and a phosphoric acid residue. They frequently have nitrogen containing bases and other constituents. They are classified in to two groups 1. Glycerophospholipids 2. Glycolipids or Sphingophospholipids

 i)Glycerophospholipids: In glycerophospholipids, the alcohol is glycerol. e.g. Phosphatidyl choline, Phosphatidyl ethanolamine, Phosphatidylserine, Phosphatidyl inositol and cardiolipin

 ii) Sphingophospholipids: In sphingophospholipids, the alcohol is sphingosine e.g. Sphingomyeline

b.Glycosphingolipids: Lipids containing a fatty acid, sphingosine and carbohydrate. e.g. Cerebrosides, Gangliosides

c.Other compound lipids: Other compound lipids include sulfolipids, proteolipids and steroids.

3. Derived lipids: These include free fatty acids, glycerol, sterols and alcohols. Fatty aldehydes, ketone bodies, hydrocarbons, lipid-soluble vitamins, and   hormone, acyglycerols (glycerides), and cholesterol.