Lipids are organic substances that are relatively insoluble in water but soluble in organic solvents. They include simple lipids like fatty acids, waxes, and glycerol; complex lipids like phospholipids, glycolipids, and lipoproteins; and derived lipids like steroids and fat-soluble vitamins. Lipids serve many important biological functions like energy storage, structural components of cell membranes, precursors to hormones, insulation, and transport of lipids between tissues.

2. Definition Classification
Biological
importance

3. organic substances relatively insoluble
in water but soluble in organic solvents
like chloroform, ether and benzene
Definition
LIPIDS

4. Simple
lipids
Complex
lipids
Derived
lipids

5. Neutral fats or Oils
Alcohol is
GLYCEROL
Waxes
Alcohol other
than glycerol

6. Uncharged

8. Esters of FA with
higher molecular
weight
monohydric
alcohols
EXAMPLES
 Lanolin
 Beeswax
 Carnauba
 Sperm whale oil
 Synthetic spermaceti

9. Subclassified according to the type of prosthetic group
Phospholipids Glycolipids Lipoproteins

10. FA + ALCOHOL + PHOSPHORIC
ACID
They
frequently
have
nitrogen
containing
bases

11. Phospholipids
may be
classified on
the basis of
the type of
alcohol
present

12. A.
Glycerophospholipids
B.
Sphingophospholipids
 Phosphatidylcholine
 Phosphatidyl
ethanolamine
 Phosphatidyl serine
 Phosphatidyl inositol
 Plasmalogens
 Cardiolipins
 Sphingomyelins

17. FA + ALCOHOL[SPINGOSINE] +
CARBOHYDRATE WITH NITROGEN BASE
Examples
Cerebrosides
Gangliosides

19. Chylomicrons
Very low density lipoprotein
(VLDL)
Low density lipoprotein
(LDL)
High density lipoprotein
(HDL)
Lipid with
prosthetic
group
PROTEIN

21. Examples
Fatty acids Steroids Cholesterol
Vitamin A
and D

22. Storage
form of
energy
Structural
component
of cell
membrane
Precursor of
many
steroid
hormones,
vitamin D
Act as
thermal
insulator
Protection
of internal
organs

23. Bile acids
help in
absorption of
fat soluble
vitamins
Lipoproteins
serve to
transport
lipids
Fats serve as
surfactants
by reducing
surface
tension
Improve food
taste and
medication
palatability
Act as
electric
insulators in
neurons