This document summarizes lipids and their classification. It defines lipids as organic compounds that are insoluble in water but soluble in organic solvents. Lipids are classified into three main categories: simple lipids, compound lipids, and derived lipids. The document also discusses the structures and functions of important lipid types such as fatty acids, triglycerides, and sterols. Fatty acids can be saturated or unsaturated and influence the melting points of lipids. Triglycerides are the main form for storing lipids and providing energy.

1. Shree Dr. R. G. Rathod Arts And Science College, Murtizapur
Department of chemistry
Seminar Topic : lipids
Class : M.Sc. Il (Sem llI )
Presented By : Ms. Devyani Prakashrao Deokar

2. Index:
 Introduction
 Defination of lipids
 Function of lipids
 Classification of lipids
1. Simple lipids
2. Compound lipids
3. Derived lipids
 Fatty Acids
1. Saturated
2. Unsaturated
 Triglycerides
 Reference

4. Introduction:
 The word lipid is derived from a Greek word “lipos” which means fats.
 Biological lipids are chemically diverse group of organic compounds which
are insoluble in water.
 They are soluble in non polar solvent such as ether, chloroform or
benzene.
 Lipids are hydrophobic in nature due to predominance of hydrocarbon
chain (-CH2-CH2-CH2-)in their structure.
 They are chief storage form of energy which gives 6-flod as much as
energy of equivalent mass of glycogen.
 Many lipids molecules are amphipathic.
 Neutral lipids upon hydrolysis yields glycerol and fatty acids.

5. Definition:
 Lipids derived as organic substance which are insoluble in water and
soluble in organic solvent, potentially related fatty acids and utilized by
living cells.
Functions of lipids:
 They serve as a storage as well as transport form of metabolic fuel.
 They provide the structural components of membrane. (phospholipids,
glycolipids, galactolipids, and sphingolipids.)
 They have protective function in bacteria, plants, insects, and vertibrates,
serving as the part of the outer coating between the body of the organism
and the environment.

6. Classification of lipids based on their chemical
composition :
 Simple lipids or homolipids: These are esters of fatty acid with various
alcohols.
 Compound lipids or heterolipids : These are esters of fatty acids with
alcohol and possess additional groups also.
 Derived lipids : These are the substances derived from simple and
compound lipids by hydrolysis.

7. Types of lipids:
 Fats: Highest category of lipids . There are two types
 Saturated : It contain single bond in carbon atom and solid at room
temperature.
 Unsaturated: It contain double bond in carbon atom and liquid at room
temperature.
 Steroid: It contain steroid lipids like cholesterol, testosterones, Estrogen, etc.
 Wax: a) wax made by bees are also lipids.
b) Human ear produce wax to protect inner ear it is also lipid.
 Vitamins: vitamins like A, D, E, and K are the fat soluble vitamins hence called
as lipids.

9. Fatty acids:
 Fatty acids are the simplest form of lipids.
 These are monocarboxylic, straight, unbranched hydrocarbon chains
containing even of carbon atoms (between 4-36)
 Fatty acids are also known as acyl group when it is a part of ester.
 Fatty acids are amphipathic in nature.
 The fatty acids may be free or esterified with glycerol to form triglycerides.
Types of fatty acids:
 Saturated fatty acids
 Unsaturated fatty acids
1. Monounsaturated fatty acids
2. Polyunsaturated fatty acids

10. Saturated Fatty acids:
 Saturated fatty acids have no double bonds in the chain or contain single
chain.
 Their general formula is CH3-(CH2)n-COOH, where n specifies the number
of methylene groups between the methyl and carboxyl carbons.
 They have higher melting points.
 They are solid at room temperature.
 Examples- lauric, myristic, palmitic acid etc.

11. Unsaturated Fatty acids:
 These fatty acid contain one or more double bonds along the length of
the hydrocarbon chain.
 They are liquid at room temperature.
 They have low melting point.
 Example, linoleic acid, oleic acid, palmitoleic acid.
 In the naturally occurring unsaturated fatty acid the double bond are in cis
configuration and trans fatty acid are produced by fermentation in the
rumen of dairy animals and are obtained from dairy products and meat.

13. Triacylglycerol:
 Triacylglycerol( triglycerides/ fats/ neutral fats) are triesters of fatty acids
and glycerol.
 They are composed of three fatty acids and a glycerol molecules.
 Triacylglycerol are of two types-
1. Simple – these contains single type of fatty acids.
2. Mixed – contains two or more different kind of fatty acids.
 Triacylglycerol are esters of glycerol with fatty acids.
 Triacylglycerol are nonpolar, hydrophobic in nature and a major form of
stored lipids.
 These molecules contain fatty acids of various length and they be
saturated or unsaturated.
 They can be distinguished as fat and oil on the basis of physical state at
room temperature.

14. Function of triacylglycerol:
 Triacylglycerol provide stored energy
 It also provides insulation.
 Partial hydrogenation of cooking oils produces trans fatty acids.
 Protect internal organs.
 Promote nutrient absorption.

16. References:
 www.britannica.com
 www.rxlist.com
 en.m.Wikipedia.org