Most lipids are referred to as simple lipids and contain the 3-carbon alcohol glycerol linked to one to three fatty acids or their derivatives.
Glycerol when linked to fatty acids is known as a glyceride.
Simple lipids are soluble in a wide variety of polar and non-polar solvents, such as n-hexane, diethyl ether, benzene, chloroform, ethyl acetate and acetone.
Fatty acids are long chain monocarboxylic acids. Fatty acids are either saturated or unsaturated and the physical properties of fatty acids with their degree of unsaturation.
Saturated fatty acids are highly flexible molecules which leads to a wide variety of conformational states of the hydrocarbon chains, due to free rotation about their single C-C bonds. The double bond of unsaturated fatty acid is always in cis-configuration.
Examples of simple lipids are triglycerides, steroids, wax ester and waxes.
Waxes are esters, simple lipid formed from a fatty acid and an alcohol. Both acid and alcohol component containing long hydrocarbon chains. Waxes are totally insoluble in water, a consequence of their hydrocarbon, non-polar, nature.
Classification of lipids: Simple lipid