Introduction and classification of lipids

LIPID CHEMISTRY



Dr Piyush Tailor
Associate Professor
Dept of Biochemistry
Govt. Medical College
Surat

,Introduction:
Definition: Lipids are organic compounds formed mainly
from alcohol and fatty acids combined together by ester
linkage.
O H2 O O

2 O H
R CH
+ HO C R 2 O
R CH C R
Fatty alcohol Fatty acid Esterase (lipase) ester (lipid)

General properties:
- Insoluble in water, but soluble in fat or organic solvents
(ether, chloroform, benzene, acetone, etc.).
- Include fats, oils, waxes and related compound.

,Biological Importance of Lipids:
Lipids are important dietary constituents, because of the
following reasons:
1. More palatable and storable to unlimited amount
compared to carbohydrates.
2. High-energy value and provide more energy per gram
than carbohydrates and proteins.
3. Supply the Essential fatty acids that cannot be
synthesized by the body.
4. Supply the body with fat-soluble vitamins (A, D, E
and K).
5. They are important constituents of the nervous
system.

, 6. Essential constituent of cell membrane and nervous
system.
7. Stored mainly in adipocytes. It is mainly triglycerides in
nature and acts as:
I. A store of energy.
II. Protect the internal organs from outside shocks.
III. A subcutaneous thermal insulator against loss of body
heat.
8. Lipoproteins, which are complex of lipids and proteins,
are important cellular constituents.
9. Cholesterol enters in membrane structure and is used for
synthesis of some hormones, vitamin D3 and bile acids.
10. Pathology of disease like Obesity, atherosclerosis is
related to lipids.