What is the composition of Lipids?

Composition and Classification

Lipids are organic compounds which are made of carbon, hydrogen and oxygen. Besides these essential components, certain other elements like phosphorus and nitrogen may be present.

To understand the classification of lipids, we must first learn some chemical terms.

A fatty acid is an organic acid containing one replaceable hydrogen and having general formula R-COOH where R represents hydrogen or a group of carbon and hydrogen atoms. Some of the common fatty acid is stearic, palmitic and oleic acids.

Glycerin or glycerol is a thick syrupy sweetish liquid, soluble in water which can react with a fatty acid. In such a reaction, one molecule of glycerol combines with three molecule is fatty acids. The hydrogen atoms of the acid are replaced and the new substance is called an ester. As three fatty acid molecules take part in the reaction, such as ester is also known as triglyceride.

All fats and oil are glycerides of fatty acids. They are natural organic compounds which occur in plant and animals and serve as storage material. The term ‘oil’ is usually applied to those which remain liquid at about 20⁰C, the other being called ‘fats’.