Transcript Online Counseling Resource YCMOU ELearning Drive…

Online Counseling Resource
YCMOU ELearning Drive…
School of Architecture, Science and Technology
Yashwantrao Chavan Maharashtra
Open University, Nashik – 422222, India
OC-SBT/ SBI/ SGS031-U02-02
Introduction
Programmes and Courses
 SEP –SBT031- Unit 02
 SEP – SBI031 – Unit 02
 SEP – SGS031 – Unit 02
School of Science and Technology, Online Counseling Resource…
Credits
 Academic Inputs by
 Mrs.Rasika Bhore
 M.sc (Microbiology)
 [email protected]
© 2007, YCMOU. All Rights Reserved.
3
School of Science and Technology, Online Counseling Resource…
How to Use This Resource

Counselor at each study center should use this presentation to deliver
lecture of 40-60 minutes during Face-To-Face counseling.

Discussion about students difficulties or tutorial with assignments should
follow the lecture for about 40-60 minutes.

Handouts (with 6 slides on each A4 size page) of this presentation should
be provided to each student.

Each student should discuss on the discussion forum all the terms which
could not be understood. This will improve his writing skills and enhance
knowledge level about topics, which shall be immensely useful for end
exam.

Appear several times, for all the Self-Tests, available for this course.

Student can use handouts for last minutes preparation just before end
exam.
© 2007, YCMOU. All Rights Reserved.
4
School of Science and Technology, Online Counseling Resource…
Learning Objectives
 After studying this module, you should be able to:
 Discuss the triglycerides with their structure & function.
 Describe physical properties & uses of oils & fats.
 Describe the types of waxes & its sources.
 Define phospholipids , glycolipids.
 Discuss various phospholipids such as gangliosides,
plasmologens, sphingolipids with their structures &
functions.
 Describe the disorders cause due to excess or depletion
or failure metabolism of all these lipids.
© 2007, YCMOU. All Rights Reserved.
5
School of Science and Technology, Online Counseling Resource…
Introduction
 Glycerides with three acyl groups that are triglycerides or
neutral fats are the main form of fatty energy storage in
animals and plants.
 Vegetable fats and oils are substances derived from plants
that are composed of triglycerides.
 Waxes are esters of fatty acids with higher molecular weight
monohydric long chain alcohols.
 Waxes have no importance as far as human metabolism is
concerned but they are widespread in nature.
 Phospholipids having hydrophobic & hydrophilic ends. There
types are- Plasmologens, sphingophospholipid.
 Gangliosides are glycoproteins, carry out many important
functions in immune system.
© 2007, YCMOU. All Rights Reserved.
6
School of Science and Technology, Online Counseling Resource…
Triglycerides or Neutral Fats









These are esters of fatty acids with glycerol.
As they are uncharged, named as neutral fats.
These are composed of three fatty acids, which are esterified
through their carboxyl groups, resulting in a loss of negative charge
& formation of neutral fat.
The fat we eat are mostly triglycerides.
Triglycerols containing the same kind of fatty acids in all three
positions are called simple triacylglycerols.
Mixed triacylglycerols contain two or more different fatty acids.
Fatty acid on C-1 is usually saturated,C-2 is unsaturated, & C-3 can
be either.
Presence of unsaturated fatty acid decreases the melting point of
lipid & remains in liquid form.
As the polar hydroxyl groups of glycerol & polar carboxyl groups of
the fatty acids are bound in ester linkages, triacylglycerols are nonpolar, hydrophobic, neutral & essentially insoluble in water.
© 2007, YCMOU. All Rights Reserved.
7
School of Science and Technology, Online Counseling Resource…
Structure of Triacylglycerol
 Hydrogen ion of the fatty acid combines with the hydroxyl
group of the glycerol, forming a triacylglycerols with release of
water molecule.
Glycerol
Fatty acids
triacylglycerol
© 2007, YCMOU. All Rights Reserved.
8
School of Science and Technology, Online Counseling Resource…
Occurrence of Triglycerides
 In many foods.
 Vegetable oils such as olive oil, corn oil.
 Plants, such as the avocado, the palm, the
fruit also contains large amounts of
triglycerides.
 Dairy products.
 They are also present in blood plasma that
derived from fats eaten in foods or made in
the body from carbohydrates.
 Calories ingested in a meal and not used
immediately by tissues are converted to
triglycerides and transported to fat cells to
be stored.
© 2007, YCMOU. All Rights Reserved.
9
School of Science and Technology, Online Counseling Resource…
Functions of Triglycerides
 Triglycerides contribute to the structure of
membranes by the formation of a lipid bilayer.
 The main biological function of triglycerides is as a
fuel.
 Provide much of the energy needed for cells to
function.
 Plants store energy in fats and oils. Oils are
particularly common in seeds, where the stored
energy helps seedlings during germination, until
they can exploit solar energy through
photosynthesis.
 Fat serves as a protective cushion and provides
structural support to help prevent injury to vital
organs such as the heart, liver, kidneys, and spleen.
© 2007, YCMOU. All Rights Reserved.
10
School of Science and Technology, Online Counseling Resource…
Be Aware………..
 Abnormally high levels of triglycerides and cholesterol are
thought to be involved in hardening of the arteries.
 Lipids may be deposited on the walls of arteries as a partial
consequence of their insolubility in the blood.
 High triglyceride levels have been associated with heart
disease.
© 2007, YCMOU. All Rights Reserved.
11
School of Science and Technology, Online Counseling Resource…
Oils & Fats




Vegetable fats and oils are
substances derived from plants that
are composed of triglycerides.
Triglyceride-based vegetable fats
and oils can be transformed through
partial or complete hydrogenation
into fats and oils of higher melting
point.
Oils are liquid at room temperature,
and fats are solid; a dense brittle fat
is called a wax.
Although many different parts of
plants may yield oil, actually oil is
extracted primarily from the seeds of
oilseed plants.
© 2007, YCMOU. All Rights Reserved.
12
School of Science and Technology, Online Counseling Resource…
Structure of Oils & Fats
© 2007, YCMOU. All Rights Reserved.
13
School of Science and Technology, Online Counseling Resource…
Physical Properties of Oils & Fats
1.
2.
3.
4.
5.
State:- fats containing saturated fatty acids are solid at room
temperature, e.g. animal fats .The plant fats posses unsaturated
fatty acids therefore liquid at room temperature.
Color, odor & taste:- when the fats are in pure state, they are
colorless, odorless & have extremely bland taste. But they are
capable of absorbing odors.
Solubility:- fats are only sparingly soluble in water, while freely
soluble in organic solvents. This solubility decreases with the
increase in chain length. Addition of hydroxyl group increases
solubility.
Melting point:- Melting point of fatty acids depends on the chain
length & degree of unsaturation. Higher the double bonds, lower the
melting point.
Specific gravity:- specific gravity of fats is less than 1,so, they
float on water. Increase in unsaturation & length of chain, increases
the specific gravity.
© 2007, YCMOU. All Rights Reserved.
14
School of Science and Technology, Online Counseling Resource…
Physical Properties of Oils & Fats
Geometric isomerism:- presence of double bond in
unsaturated fatty acids produces Cis-trans isomerism.
7. Insulation:- fats are bad conductor of heat; that means
have high insulating power. In warm blooded animals layers
of fat under skin act as a blanket.
8. Emulsification:- emulsifiers such as soaps, gums convert
the lipid mass in to small lipid droplets, called emulsification.
Fats have to be emulsified before they can absorbed by
intestinal wall.
9. Surface tension:- it is the force which held together the
surface molecules. When liquid fat is poured on water, it
reduces surface tension of water by forming unimolecular
layer on water surface.
6.
© 2007, YCMOU. All Rights Reserved.
15
School of Science and Technology, Online Counseling Resource…
Chemical Properties of Fats
1. Hydrolysis:- fats are hydrolyzed by the enzyme lipase to
yield fatty acids & glycerol.
 Reaction carried out at alkaline pH 7.5-8.5.
 The fats first splits to produce diglycerides, then
monoglycerides & finally to fatty acid & glycerol.
2. Saponification:- hydrolysis of fats by alkali is called
Saponification.
 Products of saponification are glycerol & salts of fatty acids
called soaps.
 Soaps are of 2 types:- hard soaps & soft soaps.
 Hard soaps are sodium salts of higher fatty acids while
soft soaps are potassium salts.
 Fatty acid salts of calcium, zinc, magnesium & lead are
insoluble in water.
© 2007, YCMOU. All Rights Reserved.
16
School of Science and Technology, Online Counseling Resource…
Uses of Oils



1.
2.



Inedible vegetable fats and oils such as linseed oil, tung oil, and
castor oil, used in lubricants, paints, cosmetics, pharmaceuticals, and
other industrial purposes.
Many vegetable oils are used directly as ingredients in food, example
including butter and ghee.
The oils serve a number of purposes in this role:
Texture:- oils can serve to make other ingredients to stick together.
Flavor:- oils such as almond oil, olive oil may be choosen for flavor
impact.
Many vegetable oils are used to make soaps, skin products,
perfumes and other personal care and cosmetic products.
Some oils are particularly suitable as drying agents, and are used in
making paints and other wood treatment products.
Vegetable oils are also used to make biodiesel, which can be used
like conventional diesel.
© 2007, YCMOU. All Rights Reserved.
17
School of Science and Technology, Online Counseling Resource…
Waxes




1.
2.
3.
4.
Waxes are esters of fatty acids with higher molecular weight
monohydric long chain alcohols.
In addition to beeswax, carnauba (a plant epicuticular wax), paraffin
(a petroleum wax) are commonly encountered waxes which occur
naturally.
Earwax is an oily substance found in the human ear. Some artificial
materials that exhibit similar properties are also described as wax or
waxy.
Waxes can be divided into four types:
Animal & insect waxes
Vegetable waxes
Mineral waxes
Synthetic waxes
© 2007, YCMOU. All Rights Reserved.
18
School of Science and Technology, Online Counseling Resource…
Animal & Insect’s Waxes
1. Beeswax - produced by honey
bees.
2. Chinese wax - produced by scale
insects Coccus ceriferus.
3. Shellac wax - from the lac insect
Coccus laca.
4. Spermaceti - from the head cavities
and blubber of the sperm whale.
5. Lanolin (wool wax) - from the
sebaceous glands of sheep.
© 2007, YCMOU. All Rights Reserved.
19
School of Science and Technology, Online Counseling Resource…
Vegetable Waxes
1. Bayberry wax - from the surface of the berries of the
bayberry shrub.
2. Candelilla wax - from the Mexican shrubs.
3. Carnauba wax - from the leaves of the Carnauba palm.
4. Castor wax - catalytically hydrogenated castor oil.
5. Esparto wax - a byproduct of making paper from esparto
grass.
6. Japan wax - a vegetable triglyceride (not a true wax), from
the berries of Rhus and Toxicodendron species.
7. Jojoba oil - jojoba is pressed from the seeds of the jojoba
bush.
8. Ouricury wax - from the Brazilian Feather palm.
9. Rice bran wax - obtained from rice bran (Oryza sativa).
© 2007, YCMOU. All Rights Reserved.
20
School of Science and Technology, Online Counseling Resource…
Mineral Waxes & Synthetic Waxes
1. Ceresin waxes
2. Montan wax extracted from lignite
and brown coal.
3. Ozocerite - found in
lignite beds.
4. Peat waxes
1. Polyethylene waxes based on polyethylene
2. Fischer-Tropsch waxes
3. Chemically modified
waxes - usually
esterified or saponified
4. Substituted amide
waxes
5. polymerized α-olefins
r unsaturated fatty acids.
© 2007, YCMOU. All Rights Reserved.
21
School of Science and Technology, Online Counseling Resource…
Phospholipids
 Phospholipids are fat derivatives in which one fatty acid has
been replaced by a phosphate group and one of several
nitrogen-containing molecules.
 It consists of a hydrophilic polar head group and a
hydrophobic tail.
 The polar head group contains one or more phosphate
groups. The hydrophobic tail is made up of two fatty acyl
chains.
 When many phospholipid molecules are placed in water, their
hydrophilic heads tend to face water and the hydrophobic tails
are forced to stick together, forming a bilayer.
 They are major lipid constituents of cellular membranes.
 Comprises about 40% in erythrocytic membrane & over 95%
in inner mitochondrial membrane.
© 2007, YCMOU. All Rights Reserved.
22
School of Science and Technology, Online Counseling Resource…
Structure of Phospholipids

In the example below the phosphate group is ionic and therefore
hydrophilic (orange). The fatty acid side groups are hydrophobic
(blue).
© 2007, YCMOU. All Rights Reserved.
23
School of Science and Technology, Online Counseling Resource…
Classification of Phospholipids




1.
2.
3.
4.
5.
6.

There are two classes of phospholipids: those that have a glycerol
backbone and those that contain sphingosines.
Both classes are present in the biological membrane.
Phospholipids that contain a glycerol backbone are called
phosphoglycerides (or glycerophospholipids), which are the most
abundant class of phospholipid found in nature.
Types of naturally occurring phosphoglycerides are:
Phosphatidylcholine (lecithin)
Phosphatidylethanolamine (cephalin)
Phosphatidylserine
Phosphatidylinositol
Plasmolagens and
Cardiolipin
The structural diversity is due to the variability of the chain length and
degree of saturation of the fatty acid ester groups.
© 2007, YCMOU. All Rights Reserved.
24
School of Science and Technology, Online Counseling Resource…
Plasmologens
 Plasmologens are generally similar to other
phospholipids but the fatty acid chain at C1 of
glycerol is linked through an ether bond.
 There are three major classes of
plasmologens:
1. Phosphatidalcholines
2. Phosphatidalethanolamines
3. Phosphatidalserines
 These are found in myelin & in cardiac muscle.
 Myelin contains ethanolamine plasmologens.
 Heart muscles contains choline plasmologens.
 Platelet activating factor (PAF) is plasmologens
& involved in platelet aggregation &
degranulation.
© 2007, YCMOU. All Rights Reserved.
25
School of Science and Technology, Online Counseling Resource…
Sphingophospholipids





Sphingomyelin is the major sphingosine
containing phospholipid.
The backbone of sphingomyelin is
sphingosine, an amino alcohol formed
from palmitate and serine.
The amino terminal is acylated with a
long-chain acyl CoA to yield ceramide.
Subsequent substitution of the terminal
hydroxyl group by phosphatidyl choline
forms sphingomyelin.
Sphingomyelinase, a lysosomal enzyme,
hydrolytically degrades sphingomyelin.
A genetic disorder caused by a defect in
the production of sphingomyelinase,
called Niemann-Pick disease.
© 2007, YCMOU. All Rights Reserved.
26
School of Science and Technology, Online Counseling Resource…
Functions of Sphingolipids
 Sphingolipids protect the cell surface against harmful
environmental factors by forming a mechanically stable and
chemically resistant outer leaflet of the plasma membrane lipid
bilayer.
 Certain complex glycosphingolipids were found to be involved
in specific functions, such as cell recognition and signaling.
 Simple sphingolipid metabolites, such as ceramide and
sphingosine-1-phosphate, have been shown to be important
mediators in the signaling cascades involved in apoptosis,
proliferation, and stress responses.
 In the plasma membrane and in endosomes, they perform
many of their functions, thus travelling and evolving between
organelles.
 Clinically important classes of sphingolipids are those that
confer antigenic determinants on the surfaces of erythrocytes.
© 2007, YCMOU. All Rights Reserved.
27
School of Science and Technology, Online Counseling Resource…
Gangliosides
 Gangliosides are the group of glycosphingolipids that show the
greatest structural variation and also the more complex
structure.
 This group includes molecules composed of ceramide linked
by a glycosidic bond to an oligosaccharide chain containing
hexose and N-acetylneuraminic acid (NANA, acidic sugar
known also as sialic acid) units.
 These glycosphingolipids were discovered in brain and named
by Ernst Klenk .
 They account for about 6% of the lipid weight.
 The 40+ known gangliosides differ mainly in the position and
number of NANA residues.
© 2007, YCMOU. All Rights Reserved.
28
School of Science and Technology, Online Counseling Resource…
Common Gangliosides
 Some of the common
gangliosides are:
1. GD1a
2. GD1b
3. GD2
4. GD3
5. GM1
6. GM2
7. GM3
8. GT1b
© 2007, YCMOU. All Rights Reserved.
29
School of Science and Technology, Online Counseling Resource…
Functions of Gangliosides






Gangliosides are functional ligands for maintenance of myelin
stability and the control of nerve regeneration.
Occurrence of gangliosides in cell nuclei suggests a possible
involvement of gangliosides in the expression of genes relevant to
neuronal function.
They have key functions in the immune defense systems.
They act as receptors of interferon, epidermal growth factor, nerve
growth factor and insulin and in this way may regulate cell signaling.
Gangliosides bind specifically to viruses and to various bacterial
toxins, such as those from botulinum, tetanus and cholera, and they
mediate interactions between microbes and host cells during
infections.
The best known example is cholera toxin, which is an enterotoxin
produced by Vibrio cholerae; its specific cell surface receptor is
gangliosides GM1.
© 2007, YCMOU. All Rights Reserved.
30
School of Science and Technology, Online Counseling Resource…
Disorders of Gangliosides
 Storage of excessive amounts of gangliosides GM1 in the
nerve cells in the brain and other tissues, because of failures
in the catabolic mechanism, is Tay-Sachs disease, a fatal
genetic disorder.
 Thus the nerve cells become distended and a relentless
deterioration of mental and physical abilities occurs.
 This condition is caused by insufficient activity of a specific
enzyme, β-N-acetylhexosaminidase, which catalyses the
biodegradation of gangliosides.
 A generalized gangliosidosis has been characterized in
which ganglioside GM1 accumulates in the nervous system
leading to mental retardation and enlargement of the liver.
 Impaired ganglioside metabolism may also be relevant to
Alzheimer’s disease and Parkinson’s disease.
© 2007, YCMOU. All Rights Reserved.
31
School of Science and Technology, Online Counseling Resource…
What we learn………
 Triglycerides are fatty acids with glycerol in which are
esterified by carboxyl groups, thus uncharged.
 The fats & oils we eat are almost triglycerides.
 Triglycerides act as fuel & contribute as structural component.
 Physical & Chemical properties of oils & fats.
 Animal waxes, vegetable waxes, mineral waxes & synthetic
waxes are the 4 types of waxes.
 Phospholipids such as plasmologens are found in myelin &
heart muscles.
 Sphingolipids plays very important role of protection of cell
surface & also in cell signaling & antigenic determinants.
 Gangliosides are complex molecules acts actively in immune
system.
© 2007, YCMOU. All Rights Reserved.
32
School of Science and Technology, Online Counseling Resource…
Critical Thinking Questions
1. Why some fats are liquid while others are solid at
room temperature?
2. Why the elevation in the level of gangliosides
occurs?
3. If we increase the chain of fatty acids by adding
double bonds, will it float on water?
© 2007, YCMOU. All Rights Reserved.
33
School of Science and Technology, Online Counseling Resource…
Hints for critical thinking questions
1. See physical properties if oils & fats.
2. An enzyme regulates the degradation of
gangliosides.
3. Specific gravity of oils & fats.
© 2007, YCMOU. All Rights Reserved.
34
School of Science and Technology, Online Counseling Resource…
Study Tips
 Book

Title: Principles of
Biochemistry

Author: David Nelson &
Michael Cox
 Book

Title: Biochemistry

Author: Donald Voet &
Judith Voet
© 2007, YCMOU. All Rights Reserved.
35
School of Science and Technology, Online Counseling Resource…
Study Tips
www.en.wikipedia.org
Phospholipids. Vegetable fats & oils. Sphingolipids.
www.betterhealth.gov
Fats & oils better health channel
www.biology.clc.edu
Lipids
© 2007, YCMOU. All Rights Reserved.
36
School of Science and Technology, Online Counseling Resource…
Acknowledgments
 www.tshc.fsu.edu
 www.academic.brooklyn.edu
 www.web.books.com
© 2007, YCMOU. All Rights Reserved.
37
End of the Presentation
Thank You