Fatty acids are of two types – saturated and unsaturated. Saturated fatty acids does not possess double bonds in their carbon-chains. They have a general formula of CnH2nO2.
Unsaturated fatty acids possess one or many double bonds in their carbon chains, and the general formula is CnH2nO2, e.g., oleic acid, linoleic acid, arachidonic acid.
The unsaturated fatty acid has a lower melting point than the saturated fatty acids. Most plant lipids have unsaturated fatty acids, while most animal lipids have saturated fatty acids.

Figure: Diagrammatic representation of fatty acid

Fig: Cholesterol

Fatty Acids