This document provides an overview of lipids. It begins with an acknowledgement and introduction. The introduction defines lipids as heterogenous compounds that are insoluble in water and soluble in organic solvents. Unlike other biomolecules, lipids are small molecules rather than polymers. The document then classifies lipids into four main categories: simple lipids, complex lipids, derived lipids, and miscellaneous lipids. Simple lipids include fats, oils, and waxes. Complex lipids contain additional components like phosphate, nitrogenous bases, or carbohydrates. Derived lipids result from hydrolysis of other lipids. The document provides examples of lipid types within each classification. In closing, it thanks the reader.

1. Submitted by:-Mayur Pankhi Saikia
Department:-Bsc Biotechnology
Roll No:-8
College:-Asian Institute of Management and
Technology

2. ACKNOWLEDGEMENT
I would like to express my sincere respect and
gratitude to Dr Niren Deka Sir(Principal of
Aimt),Dr Monalisha Borah Saikia Mam(HOD of
Bioscience Department) and all other faculty
members .

3. Contents
 Introduction
 Definition
 Functions
 Classification
 Bibliography

4. INTRODUCTION
 The word lipid is derived from a greek word
“lipos”which means FAT.These are heterogenous
group of compounds.
 Unlike proteins,nucleic
acids,polysaccharides,lipids are not polymers
rather they are small molecules.
 They are the chief storage form of energy,besides
their role in cellular structure and other
biochemical functions.

5. DEFINITION
 Lipids are defined as compounds which are
insoluble in water and soluble in organic solvents
such as alcohol,ether,chloroform etc.
 They are the main constituents of plant and
animal cells alongwith carbohydrate and protein.

6. FUNCTIONS
 Lipids act as a reservoir of fuel.
 They are constituents of membranes and regulate
membrane permeability.
 They are source of vitamins(A,D,E &K).
 They are important as cellular metabolic
regulators (steroid hormones and
prostaglandins).
 They protect the internal organs ,serve as
insulating materials and give shape and smooth
appearance to the body.

7. CLASSIFICATION OF LIPIDS
 Lipids are broadly classified into
SIMPLE,COMPLEX,DERIVED and MISCELLANEOUS
lipids,which are further subdivided into different
categories.
 SIMPLE LIPIDS:-They are esters of fatty acids with
alcohols .They are mainly of two types
(a)Fats and oils:-These are esters of fatty acids with
glycerol.The difference between fat and oil is only
physical.The oil is a liquid while fat is solid at room
temperature.
(b)Waxes:-Esters of fatty acids with alcohols other than
glycerol.These alcohols may be aliphatic or alicyclic.Cetyl
alcohol is most commonly found in waxes.

8.  COMPLEX LIPIDS:-These are esters of fatty acids with
alcohols containing additional groups such as phosphate
,nitrogenous bases,carbohydrate etc.They are further divided as
follows-
(a)PHOSPHOLIPIDS:-They contain phosphoric acid and
frequently a nitrogenous base.This is in addition to alcohol and
fatty acids.
(i)GLYCEROPHOSPHOLIPIDS
(ii)SPHINGOPHOSPHOLIPIDS
(b)GLYCOLIPIDS:-These lipids contain a fatty acid ,carbohydrate
and nitrogenous base.The alcohol is sphingosine ,hence are also called
as glycosphingolipids.Glycerol and phosphate are absent.Eg:-
cerebrosides,gangliosides.
(c)LIPOPROTTEINS:-Macromolecular complexes of lipids
with proteins.
(d)OTHER COMPLEX LIPIDS:-Sulfolipids ,amino-lipids and
lipopolysaccharides are among the other complex lipids.

9.  DERIVED LIPIDS:-These are the derivatives
obtained on the hydrolysis of simple lipids and complex
lipids which possess the characteristics of lipids.These
include glycerol and other alcohols,fatty acids,mono – and
diglycerols,lipidsoluble vitamins ,steroid
hormones,hydrocarbons and ketone bodies.
 MISCELLANEOUS LIPIDS:-These include a
large number of compounds possessing the characteristics
of lipids.Eg:-carotenoids,squalene terpenes etc.
 NEUTRAL LIPIDS:-The lipids which are uncharged
are referred to as neutral lipids.These are momo-,di-
,triglycerols,cholesterol and cholesteryl esters.

10. BIBLIOGRAPHY
.Books- Biochemistry by Satyanarayan

11. THANK YOU