Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st year (First Year) Biochemistry ppt lectures Topic 4 L5 Phospholipids Notes. - biochemistry notes pdf, biochemistry mbbs 1st year notes pdf, biochemistry mbbs notes pdf, biochemistry lecture notes, paramedical biochemistry notes, medical biochemistry pdf, biochemistry lecture notes 2022 ppt, biochemistry pdf.
Study Of
Compound Lipids
Compound Lipids
? Compound lipids are class of
Lipids
? Chemically Esters of Fatty acids
with Alcohols attached with
Additional groups.
? Additional Groups in Compound Lipids may
be either of these:
?Phosphoric acid
?Nitrogenous Base
?Carbohydrate moieties
?Proteins
?Sulfate groups
3 Main Compound Lipids
?Phospholipids
?Glycolipids
?Lipoproteins
Phospholipids
Phospholipids
? Compound Lipids
? Components:
? Alcohol- Glycerol/Sphingol
? Fatty Acids- PUFAs and SFAs
? Additional Group- Phosphoric acid and Nitrogenous
/Non Nitrogenous moiety
? Nature- Amphipathic
? Phospholipids (PL) Chemical y Possess:
?Fatty acids esterified to Alcohol and
?Phosphoric acid attached with
Nitrogenous /non nitrogenous base.
Types Of
Phospholipds
Based upon Alcohol
Present in Phospholipid structure
? Two Types of Phospholipids are :
?Glycerophospholipids:
Glycerol containing Phospholipids
?Sphingophospholipids:
Sphingosine/ Sphingol containing
Phospholipids.
Glycerophospholipids/
Glycerophosphatides
Names & Structures
OF
7 Glycerophospholipids
Simplest Glycerophospholipid
PHOSPHATIDIC ACID
? Depending upon Nitrogenous and Non
Nitrogenous moiety attached.
? Examples of 7 Glycerophospholipids are:
1. Phosphatidic Acid (Simplest PL)
2. Phosphatidyl Choline (Lecithin)
3. Phosphatidyl Ethanolamine (Cephalin)
4. Phosphatidyl Serine (Cephalin)
5. Phosphatidyl Inositol/ Lipositol
6. Phospatidal Ethanolamine/ Plasmalogen
7. DiPhosphatidyl Glycerol /Cardiolipin
Phosphatidic Acid
? Phosphatidic acid is a simplest
Glycerophospholipid.
? Phosphatidic acid has Glycerol esterified
with two Fatty acids at C1 and C2 .
? C3 is esterified with Phosphoric acid.
? Phosphatidic acid serve as a
precursor for biosynthesis of
other Glycerophospholipids
? Either by linking of
?Nitrogenous or
?Non nitrogenous base
Phosphatidyl Choline/Lecithin
? Phosphatidyl Choline (Lecithin) is
most commonest and abundant
Glycerophospholipid in body.
? Phosphatidyl Choline is commonly called
as Lecithin.
? Derived from word `Lecithos' meaning
Egg Yolk.
? Phosphatidic acid is linked to a
Nitrogenous base Choline to form
Phosphatidyl Choline.
Cephalins
?Type of Glycerophospholipids
?Nitrogen base is Ethanolamine
or Serine.
?Phosphatidylethanolamine and
Phosphatidylserine are
Cephalins.
Phosphatidyl Ethanolamine
Phosphatidyl Serine
? An Amino acid Serine
linked to Phosphatidic acid
forms Phosphatidyl Serine.
Phosphatidyl Inositol/ Lipositol
Phosphatidyl Inositol Tri Phosphate
(PIP3)
? Inositol/Myo Inositol a Polyol
derived from Glucose
? Non Nitrogenous ,
Carbohydrate Derivative.
? Inositol linked to Phosphatidic
acid forms Phosphatidylinositol.
? Phospahatidyl Inositol 3,4,5 Tri
Phosphate (PIP3) in presence of
enzyme Phospholipase C
? Generates Diacyl Glycerol and
Inositol Tri Phosphate.
Phosphatidalethanolamine/
Plasmalogen
? Plasmalogen possess an Ether
linkage at C1.
? Fatty acid is linked to C1 of
Glycerol, by an Vinyl(CH=CH2)
Ether (C-O-C)linkage instead of
usual Ester bond.
? Nitrogen base linked are
Ethanolamine/Choline.
Diphosphatidylglycerol/
Cardiolipin
Di Phosphatidyl Glycerol
? Cardiolipin was first isolated from
Cardiac Muscles of Calf and hence
the name derived.
? Diphosphatidylglycerol/Cardiolipin is
chemically composed of
? Two molecules of Phosphatidic acid
linked to one Glycerol .
SphingoPhospholipids/
Sphingophosphatides
? Sphingomyelin is an example
of Sphingophospholipid.
? Sphingophospholipid is
Sphingosine based Lipid
? Which has Sphingosine linked
with Fatty acid-Phosphate
and Choline.
? Sphingosine is linked with a Fatty
acid by an amide linkage to form
Ceramide.
? Ceramide is then linked to
Phosphoric acid and Choline to
form Sphingomyelin.
Properties Of Phospholipids
Amphipathic Nature Of PL
? Phospholipds are Amphipathic/
Amphiphil ic in nature.
? Since the structure of PL possess
both polar and nonpolar groups.
? Hydrophilic/Polar groups of
Phospholipids:
?Phosphoric acid
?Nitrogenous groups
? Hydrophobic/non polar groups
of Phospholipids :
?Fatty acid/Acyl chains
Exogenous And Endogenous Sources
Of Phospholipids
Occurrence And Distribution Of
Phospholipids
? Various types of Phospholipids
Associated to al over body cel s.
? Most predominantly associated to
Biomembranes
? Myelin Sheath
? Alveoli in Lungs
Functions Of Phospholipids (PL)
1. Biomembrane Components
2. Lung Surfactant
3. Lipid Digestion and Absorption
4. LCAT activity for Cholesterol Esterification and Excretion
5. Lipotropic Factor
6. Clotting Mechanism
7. Cardiolipin role
8. Coenzyme Role
9. Choline from Lecithin Methyl Donor
10. Detoxification role of Lecithin
11. Eicosanoids biosynthesis
12. Nerve Impulse Conduction
13. Second Messenger of Hormone Regulation
Glycerophospholipid Functions
Lecithin Is Most Functional Phospholipid
1. Phospholipids Components Of
Biomembranes
Phospholipid Bilayer of
Plasma membrane
Cholesterol intercalates among Phospholipids.
Cholesterol fills in the spaces left by the kinks of
PUFAs .
Cholesterol stiffens the bilayer and makes membrane
less fluid and less permeable.
? Role Of Lecithin
? The Glycerophospholipid Lecithin is
the major structural components of
biomembranes.
? An Amphipathic phospholipid bilayer
has polar head groups of PL directed
outwards.
? Membrane Phospholipid bilayer
,constituent of cel membranes
imparts:
?Membrane Structural Integrity
?Membrane Fluidity
?Membrane Flexibility
?Selective Permeability
? Phospholipids may have fatty
acids which are saturated or
unsaturated.
? This affects the properties of
the resulting bilayer/cel
membrane:
?Most membranes have
phospholipids derived from
unsaturated fatty acids.
?Unsaturated fatty acids add
fluidity to a bilayer since
`kinked' tails do not pack
tightly together.
? Phospholipids (PL) derived from unsaturated
phospholipids al ow faster transport of
nonpolar substances across the bilayer.
? Polar substances are restricted to cross
the membrane .
? PL bilayer in membranes protect the cel
from an entry of polar reactive and
interfering substances and serve as
security guards of cel s.
? Membranes of Nerve cel s, which
are stiffer contain a much higher
percentage of phospholipids
derived from saturated fatty acids.
? They also contain high levels of
Cholesterol which stiffens
membrane structure.
2.Phospholipid As Lung Surfactant
? DiPalmitoyl Phosphatidyl Choline serve
as an Lung surfactant.
? It Lowers surface tension and keeps
Alveoli of lungs blown. (prevent
adherence of alveoli)
? Enables effective exchange of gases
(Oxygen) in Lungs.
? After expiration of air the
alveoli gets deflated.
? The lung surfactant reduces
the surface tension and al ow
the alveolar wal s to
reinflate.
?Phospholipid as Lung
surfactant
?Prevent body to suffer
from Respiratory Distress
Syndrome (RDS).
3.Phospholipids
Help In Digestion And Absorption Of
Dietary Lipids
? Phospholipids being amphipathic
in nature act as good emulsifying
agents.
? Along with Bile Salts they help in
digestion and absorption of non
polar dietary Lipids.
4.Phospholipid Lecithin
Helps In Cholesterol Excretion
? Lecithin helps in Cholesterol
Esterification by LCAT activity.
? Cholesterol Ester is later
dissolved in Bile and further
excreted it out.
? Lecithin serve as a storage depot
of Choline.
? Choline is a store of labile Methyl
groups
? Hence Choline participate in
Transmethylation reactions .
? Choline is used for generation of
neurotransmitter `Acetyl Choline"
which helps in nerve impulse
transmission.
? Choline serve as Lipotropic factor
hence helps in Lipoprotein formation in
Liver to mobilize out Lipids and prevent
from Fatty Liver.
6. Phospholipids Releases
Arachidonic Acid For Eicosanoid
Biosynthesis
? Lecithin at 2nd carbon has
Arachidonic acid (PUFA).
? It donates Arachidonic acid which
is a precursor for Eicosanoid
biosynthesis.
? Phosphatidyl Inositol also
provides Arachidonic acid for
Eicosanoids biosynthesis.
?Lecithin helps CYT450
system for drug
detoxification.
8. Phospholipids Has Role
In Blood Coagulation
? Role Of Cephalin
? Phosphatidyl Ethanolamine has
role in blood coagulation.
? It converts clotting factor
Prothrombin to Thrombin by
factor X.
? Phosphatidyl Serine has role
in Apoptosis (Programmed
Cel death).
10.Role Of Phospholipids In
Hormonal Action
Mediates Cel Signal Transduction
? Role Of Phosphatidylinositol
? Phosphatidyl Inositol
Triphosphate (PIP3) is a
constituent of cel membrane
? It mediate hormone action /cel
signal transduction and maintain
intracel ular Calcium.
? Inositol tri phosphate and Diacylglcerol
are released from PIP3 by membrane
bound Phospholipase C
? The Inositol triphosphate and DAG
serve as second messenger to hormones
Oxytocin and Vasopressin.
?Plasmalogen
associated to brain and
muscles helps in Neural
functions.
? Role Of Cardiolipin
? Cardiolipin is rich in inner
mitochondrial membrane and
supports Electron Transport
Chain and cellular respiration.
? Cardiolipin exhibits
antigenic properties and
used in VDRL serological
tests for diagnosis Syphilis.
? Phospholipid serve as Coenzyme
for certain Enzymes :
?Lipoprotein Lipase
?Cytochrome Oxidase
Functions OF Sphingophospholipids
? Sphingomyelins are rich in
Myelin sheaths which surrounds
and insulate the axons of
neurons.
? Sphingomyelin helps in nerve
impulse transmission.
Disorders Related To Phospholipids
? Respiratory Distress Syndrome
(RDS)
? Suffered by premature born infants.
? Caused due to deficiency of Lung
surfactant DiPalmitoyl Phosphatidyl
Choline.
? Since Lung is last organ to mature.
? Premature babies has insufficient lung
surfactant lining in the alveoli walls.
? Which supports no normal respiration.
? Has respiration difficulties due to
alveolar col apse.
?Signs And Symptoms Of
RDS
?Low ATP production
?Weakness ,Lethargy
?Low Cellular Functions
?Poor Coordination
Lecithin/Sphingomyelin (L/S) Ratio
of Amniotic Fluid
Assessment Of Fetal Lung Maturity
And
Diagnostic Criteria For RDS
? Lecithin /Sphingomyelin (L/S)
ratio of amniotic fluid, col ected
by Amniocentesis is a good
indicator to evaluate fetal lung
maturity.
? Prior to 34 weeks of gestation the
concentration of Lecithin and
Sphingomyelin in amniotic fluid is
equal.
? In Later weeks of gestation the
Lecithin levels are markedly increased.
? At ful term L/S ratio is > 2/>5
? In pre term infants L/S ratio
is 1.5 or < 1 results to suffer
from RDS.
OTHER RDS Sufferers
Individual with Lung Damage and
Dysfunctions
? Old aged Persons
? Smokers
? Severely Infected Lungs
? Lungs toxicated and damaged by chemicals
? Old age persons and Adults with
Lung damage
(Due to Smoking/ Infections)
? Who unable to biosynthesize the
lung surfactant may also exhibit
RDS.
Prevent And Manage RDS
? Pregnant Women Diet for biosynthesis of L and S
? Pregnant Women Activities and Positions
? Prevent Damaging Environment Exposures
Membrane Related Disorders
Due To Defective Phospholipds
Multiple Sclerosis Due to Defect In
Sphingomyelins and Myelin Sheaths
Defect In Sphingomyelins
May Affect
Nerve Impulse Conduction
Membrane Carbs,Lipids and Proteins
Structural y Important For Functional Role
? Deranged Cellular Environment
? Cell membrane Damage
? Tissue Necrosis
? Cell Death
Mitochondrial Electron Transport Chain
Defects
Due to Phospholipid Deficits
Fatty Liver
Due to Phospholipid Defects
This post was last modified on 05 April 2022