Classification of Lipids

Classification of Lipids : this lecture by Lecturer of Biochemistry K.A.

We can classify the lipids on the basis of two criteria:
(1) Structural complexity
(2) Biological functions they perform in living organisms.
(1) Structural Complexity
1. Simple lipids: Esters of fatty acids with various alcohols.
a- Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid
b- Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols.
2. Complex lipids: Esters of fatty acids containing groups in addition to an alcohol and a fatty acid.
a- Phospholipids: Lipids containing, in addition to fatty acids and an alcohol, a phosphoric acid residue. They frequently have nitrogen-containing bases and other substituents, eg, in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine.
b- Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine, and carbohydrate.
c- Other complex lipids: Lipids such as sulfolipids and aminolipids. Lipoproteins may also be placed in this category.
3. Precursor and derived lipids: These include fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, and ketone bodies, hydrocarbons, lipid-soluble vitamins, and hormones. Because they are uncharged, acylglycerols (glycerides), cholesterol, and cholesteryl esters are termed neutral lipids.