Question

make a compersion betwwen simple lipids ,compound lipids and derived lipids

Answer 1

Lipids are important constituent of of the diet because they are a source of high energy value. Lipids are also important because of the fat-soluble vitamins, and essential fatty acids found in the fat of the natural food stuffs. Body fat serves as a very good source of energy, it is stored in adipose tissues. They also act as insulating material in the subcutaneous tissues and are also seen around certain organs. Lipids combined with proteins are important constituents of the cell membranes and mitochondria of the cell. Lipids are not generally macromolecules.

Simple Lipids or Homolipids

Simple lipids are the esters of fatty acids with various alcohols.

Fats and Oils (triglycerides and triacylglycerols) - These are esters of fatty acids with a trihydroxy alcohol, glycerol. A fat is solid at ordinary room temperature, an oil is liquid.

Compound Lipids or Heterolipids

Heterolipids are esters of fatty acids with alcohol and possess additional groups also.

Phospholipids or Phosphatids are compound containing fatty acids and glycerol in addition to a phosphoric acid, nitrogen bases and other substituents. They usually possess one hydrophilic head and tow non-polar tails. They are called polar lipids and are amphipathic in nautre.

Phospholipids can be phosphoglycerides, phosphoinositides and phosphosphingosides.

Phosphoglycerides are major phospholipids, they are found in membranes. It contains fatty acid molecules which are esterified to hydroxyl groups of glycerol. The glycerol group also forms an ester linkage with phosphoric acid. Example: Lecithin, Cephalins.

Derived Lipids

Derived lipids are the substances derived from simple and compound lipids by hydrolysis. These includes fatty acids, alcohols, monoglycerides and diglycerides, steroids, terpenes, carotenoids.

The most common derived lipids are steroids, terpenes and carotenoids.

Steroids do not contain fatty acids, they are nonsaponifiable, and are not hydrolyzed on heating. They are widely distributed in animals, where they are associated with physiological processes. Example: Estranes, androstranes, etc.

Answer 2

The key difference between simple and complex lipids is that simple lipids are esters of fatty acids with alcohols and do not carry other molecules while complex lipids are fatty acids with alcohols and other molecules such as phosphates, nitrogenous base, etc.