question_answer 46)

  Describe various forms of lipid with a few examples.

Answer:

                  Lipids are the esters of higher fatty acid with alcohol, such as glycerol, etc. These can be classified as 1.                   Simple Lipids are esters of fatty acids with alcohol. 77?ese may be (i)FatsThese are esters of higher fatty acids with glycerol (triglycerides). (ii) WaxesThese are esters of higher fatty acids with alcohol other than glycerol. 2.                   Compound or conjugated lipids, are those compounds which contain simple lipids and prosthetic (other additional) group. They include (i) Glycerophospholipids, also known as phospholipids in which one of the fattyacid is replaced by phosphoric acid which is linked to nitrogenous groups like choline, ethanolamine, serine etc, e.g., Lecithin and cephalin, etc. (ii)Sphingolipids, are lipids having phosphoric acid with amine alcohol 4-sphinganine or sphingosine instead of glycerol in addition to fatty acid and choline. (iii) Glycolipids,i.e., those which contain spinganine  with a fatty acid and amonosaccharide sugar, e.g.,cerebrosides and gangliosides. 3.                   Steroids are compounds with different chemical nature but similar physical properties. Their structure is based upon a 4 ring cyclopentenoperhydrophenanthrene ,e.g., cholesterol. 4.                   Prostoglandins are derivatives of arachidonic acid and contain 20 C-atoms. These are biologically active lipids.