Lipids and Classification of Lipids

Lipids

The lipids include a large number of biomolecules of different types. The term lipid originated from a Greek word ‘Lipos’ meaning fat.

In general, those constituents of the cell which are insoluble in water and soluble in organic solvents of low polarity (such as chloroform, ether, benzene etc.) are termed as lipids. Lipids perform a variety of biological functions.

Classification of Lipids

Lipids are classified into three broad categories on the basis of their molecular structure and the hydrolysis products

(i)       Simple Lipids: Those lipids which are esters and yield fatty acidsand alcohols upon hydrolysis are called simple lipids. They include oils, fats and waxes.

(ii)    Compound Lipids: Compound lipids are esters of fatty acids andalcohol with additional compounds like phosphoric acid, sugars, proteins etc.

(iii)  Derived Lipids: Compounds which are formed from oils, fats etc.during metabolism. They include steroids and some fat soluble vitamins.