Lipids are naturally occurring organic compounds that are insoluble in water but soluble in non-polar solvents like ether, chloroform or benzene. Examples include fats, oils, waxes, sterols and fat soluble vitamins.
Simple lipids are the esters of fatty acids. Example: triglycerides and waxes.
Compound lipids are esters of fatty acids with additional groups such as phosphates. Example: phosphoglycerides and phosphoinositides
The hydrolysis products of simple and compound lipids are called derived lipids.
For example hydrolysis of triglycerides yields glycerol and fatty acid.
Similarly steroids, fatty aldehydes, ketones, alcohols, fat-soluble vitamins can also be derived from the hydrolysis of simple/compounds lipids.
· Lipids are important components of the cell membrane and are necessary for the structural integrity of the cell.
· They serve as energy reserve of the body.
· They act as a protective coating in aquatic organisms.
· Lipids serve as insulating material on the surface of animals living in extreme cold regions.
· They serve as component of cell recognition, species specificity and tissue immunity.
· They help in the absorption and transport of fat soluble vitamins.