13.3 Lipids

Lipids are macromolecules made up of fatty acids. Lipids include oils and fats. Oils and fats are esters of long chain carboxylic (fatty) acids with glycerol. These esters are made of three fatty acids, therefore, they are called triglycerides. General formula of triglycerides is as under.

Oils exist in liquid form at room temperature. They are triglycerides of unsaturated fatty acids. While fats exist in solid form at room temperature. They are triglycerides of saturated fatty acids.

13.3.1 Fatty Acids

Fatty acids are building blocks of lipids. They are long chain saturated or unsaturated carboxylic acids. Examples are:

These acids form esters (oils or fats) with glycerol in the presence of mineral acids.