Principles of Biochemistry

6.2.1.1 Structure of Simple Lipids

a) Triglycerides or triacylglycerols

A triglyceride is a lipid formed by the esterificatin of three fatty acid to a glycerol. Triglycerides or triacylglycerols are the main energy storage material. 

A simple triglyceride is fin which the three glycerol hydroxyl groups are esterified  with  three identical fatty acid molecules. A mixed triglyceride contains two or three different fatty acids in ester combination.  They are present in the adipose tissue present under the skin, in the abdominal cavity, in the mammary glands and around vital organs. The fats and oils that occur in plants and animals are mixed triglycerides.

b)Waxes

Waxes are esters of fatty acids having 14 to 36 carbon atoms with long chain mono hydroxy alcohols having 16 to 22 carbon atoms. Waxes are secreted by certain insects, skin glands as a protective coating to keep skin and furs of animals and the leaves and fruits of plants. Waxes are formed and used in large amounts is marine life especially in plankton organisms in which waxes serve as energy storage compound. Waxes are major food and storage lipids in whales, herring, salmon and many other marine species.