General Veterinary Biochemistry

Introduction and functions of lipids

LIPIDS

• Lipid is a general term for water- insoluble biological molecules.
• They are structurally and functionally diverse group of molecules.
• Lipids are organic substances soluble in organic solvents such as chloroform, ether, benzene, ethanol and other non-polar solvents.
• The lipids include fatty acids, fats, oils, waxes and related compounds such as phospholipids, eicosanoids, terpenes and steroids.

Functions of lipids

• They are stored forms of energy in all living organisms. Fat molecules have maximum number of hydrogen atoms so, they have maximum of electrons, which produce more energy as ATP.
• They are structural components of the cell.
• The fatty acid, arachidonic acid is the precursor for all prostaglandins, leukotrienes and thromboxanes.
• The lipids are needed in the diet to solubilize the fat-soluble vitamins like A, D, E and K.
• The corticosteroids, sex hormones and Vitamin D are synthesized from cholesterol.
• Phosphatidylinositol triphosphate serves as the key precursor in the formation of second messenger.
• Lipids act as an insulating material, which prevents the dissipation of heat from the body.
• Lipids provide cushioning effect to the body which prevents the body against mechanical injuries.
• Because lipids are insoluble, they generate no osmotic pressure when stored in the cells.