Moazzam Ali Shahid
Senior Lecturer (Molecular Medicine)
Senior Research Officer (Research)
PhD Scholar (Biochemistry)

 Classification
◦ Simple
◦ Complex
◦ Derived
 Nomenclature
 Properties
 Biomedical importance

 The lipids are a heterogeneous group of
compounds, including fats, oils, steroids,
waxes, and related compounds, which are
related more by their physical than by their
chemical properties.
 Most membrane lipids are amphipathic, having a
non-polar end and a polar end.

They have the common property of being
relatively
◦ Insoluble in water and
◦ soluble in nonpolar solvents such as ether and
chloroform and acetone
 Lipids include
◦ Triacylglycerols, phosphodiacylglycerols,
sphingolipids, glycolipids, lipid-soluble
vitamins, and prostaglandins
◦ cholesterol, steroid hormones, and bile acids

SIMPLE
COMPLEX
DERIVED

Esters of fatty acids with various alcohols.
A. Fats:
Esters of fatty acids with glycerol.
Oils are fats in the liquid state.
B. Waxes: Esters of fatty acids with higher
molecular weight monohydric alcohols

 Structure:
◦ glycerol (3C alcohol) + fatty acid
dehydration synthesis
 fatty acid =
long HC “tail” with COOH group at “head”
enzyme

Nomenclature

Saturated acids end in -anoic,
eg, octanoic
Unsaturated acids with double bonds end
in -enoic,
eg, octadecenoic acid (oleic acid).

Some fatty acids and their common names:
14:0 myristic acid;
16:0 palmitic acid;
18:0 stearic acid;
18:1 cisD9 oleic acid
18:2 cisD9,12 linoleic acid
18:3 cisD9,12,15 a-linonenic acid
20:4 cisD5,8,11,14 arachidonic acid
20:5 cisD5,8,11,14,17 eicosapentaenoic acid (an omega-3)
Double bonds in fatty acids
usually have the cis
configuration.
Most naturally occurring fatty
acids have an even number of
carbon atoms.
C
O
O
1
2
3
4
a


fatty acid with a cis-D9
double bond

There is free rotation about C-C bonds in the fatty
acid hydrocarbon, except where there is a double
bond.
Each cis double bond causes a kink in the chain.
Rotation about other C-C bonds would permit a
more linear structure than shown, but there would
be a kink.
C
O
O
1
2
3
4
a


fatty acid with a cis-D9
double bond

18:0 stearic acid;
18:1 cis*9 oleic acid
18:3 cisD9,12,15 a-linonenic acid