7. GLYCEROL
WITH NITROGENOUS BASE WITHOUT NITROGENOUS BASE
1) LECITHIN
(Phosphatidylcholine)
2) CEPHALINS
(Phosphatidylethanolamines)
3) PHOSPHATIDYLSERINE
4) PLASMALOGEN
1) CARDIOLIPINS
(Diphosphatidylglycerol)
2) PHOSPHATIDYLINOSITOL
8. 1) PHOSPHATIDIC ACID
( diacylglycerol 3-phosphate)
Simplest glycerophospholipid.
Forms the key element in the synthesis of other glycerophospholipids
FATTY ACID
FATTY ACID
G
L
Y
C
E
R
O
L
PHOSPHATE
9. 2) PHOSPHATIDYLCHOLINE( LECITHIN)
• phospholipid of cell membrane ( 50%)
• Formation of lipoprotein
• Esterification of cholesterol
• Serve as important neurotransmitter
acetylcholine
G
L
Y
C
E
R
O
L
Fatty acid
Fatty acid
Phosphate
choline
10. 3) DIPALMITOYL LECITHIN
Major constituent of lung surfactant
Secreted by pulmonary type II epithelial cells
Surfactant reduces surface tension in the alveoli prevents adhesion of inner
surfaces of the lungs.
Absence of surfactant results in respiratory distress syndrome (RDS)in
premature infants
G
L
Y
C
E
R
O
L
PALMITOYL FA
PALMITOYL FA
PHOSPHATE
CHOLINE
11. 4) PHOSPHATIDYLETHANOLAMINE
( CEPHALIN)
• THROMBOPLASTIN ( coagulation
factor III) required for clotting
process is composed mainly
cephalins
G
L
Y
C
E
R
O
L
PHOSPHATE
ETHANOLAMINE
FATTY ACID
FATTY ACID
12. 5) PHOSPHATIDYLSERINE
• 10% OF phospholipid in
mammals
• Component of biological
membrane
• Key role In cell cycle signaling in
apoptosis ( programmed cell
death )
G
L
Y
C
E
R
O
L
Fatty acid
phosphate
serine
Fatty acid
13. 6) PLASMALOGEN
3 major classes
Phosphatidylcholine
Phosphatidalethanolamines
Phosphatidalserines
Found in myelin,cardiac muscle
Platelet activating factor( PAF) is a
plamalogen
Protective effect against reactive
oxygen species
G
L
Y
C
E
R
O
L
Fatty acid
Fatty acid
phosphate
ethanolamine
14. 7) PHOSPHATIDYLINOSITOL
• Acts as a second messenger for
the action of hormones.
Oxytocin and vasopressin
G
L
Y
C
E
R
O
L
Fatty acid
Fatty acid
phosphate
Myo inositol
15. 8) DIPHOSPHATIDYLGLYCEROL ( cardiolipin)
• Major lipid of mitochondrial membrane
• Necessary for ETC
• Only antigenic phospholipid
G
L
Y
C
E
R
O
L
Fatty acid
Fatty acid
phosphate
glycerol
phosphate
G
L
Y
C
E
R
O
L
Fatty
acid
Fatty
acid
17. sphingomyelin
ceramide+ phosphate+nitrogenous base
Basic structural unit of all spingolipids
• One of principal structural lipid of
membrane of nerve tissue ( myelin
sheath )
• Act as electrical insulators around
nerve fibres
• Key role in cell signalling, apoptosis
Palmitic acid + serine
S
P
H
I
N
G
O
S
I
N
E
Fatty acid
CERAMIDE
S
P
H
I
N
G
O
S
I
N
E
Fatty acid
phosphate
choline
18. Functions of phospholipids :
• Major lipid constitute of cellular membranes
• Regulate permeability of membrane
• Good emulsifying agents and help in intestinal absorption of lipids
• Constituent of lipoproteins
• Lecithin represent a storage form of lipotropic factor ,choline and
methyl group
• Lecithin acts as a lung surfactant which prevents alveolar collapse
19. • Thromboplastin is composed of mainly of cephalins
• Phosphatidylinositol is a second messenger
• Plasmalognes involved in platelet aggregation
• Sphingomyelin act as electrical insulators around nerve fibres
• Cardiolipin is necessary for ETC
20. PHYSICAL PROPERTIES :
When purified it is a waxy, white
substance, becomes brown when
exposed to air (autooxidation)
CHEMICAL PROPERTIES :
• When aqueous solution of
lecithins are shaken with H2SO4,
choline is split off, forming
phosphatidic acid.
• When lecithins are boiled with
alkalies or mineral acids, not
only choline is split off,
phosphatidic acid is further
hydrolysed to glycerophosphoric
acid and two molecules of fatty
acids
21. Micelles
phospholipid is amphipathic in
nature.
It has a hydrophilic or polar head
(phosphate group attached to
choline, ethanolamine, inositol,
etc.) and a long hydrophobic tail
containing two fatty acid chains.
In aqueous systems the polar
phospholipid spontaneously
disperse to form micelles, in which
the hydrocarbon tails of the
phospholipid are hidden from the
aqueous environment and
electrically charged hydrophilic
heads are exposed on the surface
facing the aqueous medium
22. Lipid Bilayer
Phospholipids also readily and
spontaneously form a very thin
bilayer separating two aqueous
compartments.
In these structures, the
hydrocarbon tails of the
phospholipid molecules extend
inward from the two surfaces to
form a continuous inner
hydrocarbon core and the
hydrophilic heads face outwards
extending into the aqueous
phase
23. Liposomes
Liposome (Artificially Formed Phospholipid
Vesicles)
Liposomes are artificially formed aqueous
vesicles enclosed by a lipid bilayer.
In the laboratory, liposomes (lipid bilayer) are
formed by suspending phospholipid in an
aqueous medium and then sonicating, i.e.
agitating by high frequency sound waves to
give a dispersed closed vesicles. Vesicles
formed by these methods are nearly spherical
in shape and have a diameter of about 5 nm.
Liposomes can be used to study membrane
permeability or to deliver drugs to cells
