Knowledge about Polysaccharides

1. Polysachharides
Keshav Jaiswal
M.Sc.
Bio Tech. 1st sem.

2. content :-
Carbohydrates
Classification of carbohydrates
Polysachharides
Types
Homopolysachharides
Heteropolysachharides
Conclusion
Summary
Refrensh

3. Carbohydrates
Chemically carbohydrates may be defined as
polyhydroxy aldehyde OR polyhydroxy ketone
OR
Their polymerization products that yield such
polyhydroxy aldehyde OR polyhydroxy ketone on
hydrolysis
Also called hydrolysis of carbon
Composed by C , H , O elements.
Common formula is CnH2nOn OR (CH2O)n

4. Classification of carbohydrates
Carbohydrates
Monosaccharides Oligosaccharides Polysaccharides
Trioses - Dihydroxy acetone
Tetraoses - Arithrose
Pentoses - Ribose
Hexoses - Glucose
Disaccharides
Sucrose , Lactose
Trisaccharides
Raffinose
Homopolysaccharides Heteropolysaccharides
Glucosans Galactosans Fructosans
•Starch
•Glycogen
•Cellulose
•Chitin
•Agar •Inulin
•Mucopolysaccharides
~Hyaluronic acid
~Heparin
•Murein

5. Polysaccharides
 "Polysaccharides are the complex carbohydrates. They are
made up of chains of monosaccharides which are linked
together by glycosidic bonds”
common formula Cx(H2O)y
structure are often linear , but may contain various degree of
branching
Also called “Polymeric anhydrides of monosaccharides”
Colourless , testless

6. Types of Polysaccharides
2 types
1. Homopolysaccharides
2. heteropolysaccharides
* Homopolysaccharides :-
Also known as HOMOGLYCANS
Formed by one types of monosaccharides

7. Glucosans
Starch
stored from of sugar in plants.
starch present in maize 60% , wheat 70% , rice 75% & potato 80%.
Monomer - alpha glucose.
composed of 20-30% amylose and 70-80% amylopectin depending on the source

8. Amylose
Also known as Alpha amylose
 Linear polymer of alpha D glucose
 Linked by Alpha 1-4 glycosidic linkage
Molecular weight range between 50000 to
200000
Amylopectin
Also known as beta amylose
Highly branched polymer
Glucose molecule are linked by 1-4
glycosidic linkage and branched chain are
linked by 1-6 glycosidic linkage
Branching at every 25-30 glucose molecule
Molecular weight range between 70000-
100000
Types of Starch

9. Suspension of amylose in water
adopt a helical confirmation
Iodine(I²) can insert in the middle
of the amylose helix to give a blue
colour that is characteristic and
diagnostic for starch.
Starch

10. Glycogen
Also known as animal starch.
Stored in muscle and liver.
Contains both Alpha 1-4 linkes and Alpha 16 branches at
every 8-12 glucose.
Complete hydrolysis yield glucose

11. Glycogen
 in the liver , glycogen synthesis and degradation are
regulated to maintain blood glucose levels as required to as a
buffer to maintain blood glucose level
In contrast , in muscle , these process are regulated to
meet the energy needs of the muscles itself.

12. Cellulose
Main / primary component of plant cell wall.
Polymer of beta d glucose are linked by beta 1-4 linkages.
Most abundant of all carbohydrates.
Testless and insoluble in water and most organic solvent.
Common source - wood , cotton ETC.

13. cellulose consists of beta D glucopyranose units linked by
beta 1-4 bonds from long , straight chain strengthened by
cross-linking hydrogen bonds.
Cellulose

14. oMammals lake any enzyme that hydrolyzes the beta 1-4 bonds ,
and so cannot digest cellulose . It is the major component of dietary
fiber , microorganism in the gut of ruminants and other herbivores
can hydrolyze the linkage and ferment the product to short chain
fatty acids as a major energy source.
Cellulose digestion

15. Agar
Obtained form the cell walls of some species of red algae.
Dissolved in hot water and cooled agar becomes gelatinous.
Chief use in a culture medium.
Agar is a galactose polymer , In which both type of galactose (D & L form) are found.
By hydrolysis of agar , D & L galactose is usually found in 9:1.-The 9 recidue of D-
galactose are linked by 1-3 beta glycosidic bond & the last D-galactose of chain is joined
by one molecule of L-galactose with on ester of H2SO4 at C6
Galactosans

16. Inulin
Beta 2-1 linked fructofuranoses.
Linear.
Colour yellow with iodin.
Lower molecular weight than starch.
Hydrolysis yield fructose.
Source including onion , garlic etc.
Used as a fat / cream substitute.

17. Chitin
 2nd most abundant carbohydrate
Polymer – N Acetyl glucosamine
Linkage beta 1-4 glycosidic bonds.
Present in the cell wall of fungi and exoskeleton of
crustaceans , insect and spider.
Chitin is used commercially in coating (extand the cell
life of fruits & meats)
Fructosans

18. * Heteropolysaccharides :-
Also called Heteroglycans.
Composed different types of sugar / sachharides.
Mucopolysaccharides-
Commonly known as glucosamino glycans (GAG)
They are containing repeating units of sugar derivatives (amino /
uronic acid)
Ex. - Hyaluronic acid , Heparin etc.

19. [A] Hyaluronic acid
D-glucronic acid and N-acetyle D-glucosamine.
Linkage in this to molecular are beta 1-3 glycosidic bonds.
Soluble in water- polymers are very large (100-10,000 kDa).
Present in connective tissue and forms a gel around.

20. [B] Heparin
An anticogulant.
Occure in blood , kidney , liver etc.
Polymer - glucronic acid & N-acetyl glucosamine.

21. Murein
Linear chain of 2 amino sugar.
Polymer - N-acetyle glucosamine & N-acetyle muramic acid.
Linkage - beta 1-4 glycosidic bonds.
Murein serves structural role in the cell wall of bacteria giving
structural strength and rigidity.

22. Summary
-Homopoysaccharides are polymers of similar monomer
monosaccharides linked together by Glycosidic linkages.
Structurally they may be Glucosans, fructosan or Galactosan.
Functionally they may be storage or structural polysaccharides.
Heteropolysaccharides are polymers of a repeating disaccharide
units with enormous diversity. They are components of joints,
cartilages etc. Heparin is an anticoagulant.

23. Conclusio
n
Thus polysaccharide is formed of monosaccharide units and
is of great biological importance to us.
The three main function of polysaccharides are providing
structural support , storing energy & sending cellular
communication signals.
Linear molecule , like - cellulose & chitin are strong and rigid.

24. Refrens
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# Dr. Tej Bahadur Singh - Biochemistry (new edition)
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