Carbohydrates Classification

1. Mrs. Prajakta B. Kothawade
Assistant Professor,
PES Modern College of Pharmacy, for ladies, Moshi, Pune

2. Carbohydrates are Polyhydroxy aldehydes or ketones, or
substances that yield such compounds on hydrolysis.
General formula : (CH2O)n

3. • Monosaccharides – carbohydrates that cannot be hydrolyzed
to simpler carbohydrates; eg. Glucose or fructose.
• Oligosaccharides – carbohydrates that can be hydrolyzed into
a few monosaccharide units; eg. Sucrose or lactose
• Polysaccharides – carbohydrates that are polymeric sugars; eg
Starch or cellulose

4. • Monosaccharides Contains 3-9 carbon atom sugars.

7. Ketone Aldehyde
4 Tetrose Tetrulose
5 Pentose Pentulose
6 Hexose Hexulose
7 Heptose Heptulose
8 Octose Octulose
Number
of
carbons

8. • Oligosaccharides contains 2-10 monosaccharide units
joined by glycosidic bonds.
-OH group of one monosaccharide joined to -OH group
of another monosaccharide .
• Links may be a or b
• Link around glycosidic bond is fixed but anomeric forms
on the other C-1 are still in equilibrium.

10. Polysaccharides are complex carbohydrates made up
More than 10 linked monosaccharide units.
• Nomenclature:
Homopolysaccharide-a polysaccharide is made up of one type of
monosaccharide unit.
Heteropolysaccharide-a polysaccharide is made up of more than one type of
monosaccharide unit.
• Starch and glycogen are storage molecules
• Chitin and cellulose are structural molecules
• Cell surface polysaccharides are recognition molecules

12. Some types of polysaccharides
1.Starch
• Starch is a storage compound in plants, and made of
glucose units
• It is a homopolysaccharide made up of two components:
amylose and amylopectin.
• Most starch is 10-30% amylose and 70-90%
amylopectin

13. • Amylose – a straight chain structure formed by 1,4 glycosidic
bonds between α-D-glucose molecules.
H O
OH
H
OH
H
OH
CH2OH
H
O H
H
OH
H
OH
CH2OH
H
O
H
H H O
O
H
OH
H
OH
CH2OH
H
H H O
H
OH
H
OH
CH2OH
H
OH
H
H O
O
H
OH
H
OH
CH2OH
H
O
H
1
6
5
4
3
1
2
amylose
Structure of Amylose Fraction of Starch

14. • The amylose chain forms a
helix.
• This causes the blue colour
change on reaction with
iodine.
• Amylose is poorly soluble in
water, but forms micellar
suspensions
Amylose

15. Amylopectin-a glucose polymer with mainly α -(14)
linkages, but it also has branches formed by α -(16)
linkages. Branches are generally longer than shown above.
H O
OH
H
OH
H
OH
CH2OH
H
O H
H
OH
H
OH
CH2OH
H
O
H
H H O
O
H
OH
H
OH
CH2
H
H H O
H
OH
H
OH
CH2OH
H
OH
H
H O
O
H
OH
H
OH
CH2OH
H
O
H
O
1 4
6
H O
H
OH
H
OH
CH2OH
H
H H O
H
OH
H
OH
CH2OH
H
H
O
1
OH
3
4
5
2
amylopectin
Structure of Amylopectin Fraction of Starch

16. • Amylopectin causes a red-
violet colour change on
reaction with iodine.
• This change is usually
masked by the much
darker reaction of
amylose to iodine.
Amylopectin
Amylopectin

17. Starch therefore consists of amylose helices entangled on
branches of amylopectin.

18. 2 Glycogen
• Storage polysaccharide in animals
• Glycogen constitutes up to 10% of liver mass and 1-2% of muscle
mass
• Glycogen is stored energy for the organism
• Similar in structure to amylopectin, only difference from starch:
number of branches
• Alpha(1,6) branches every 8-12 residues
• Like amylopectin, glycogen gives a red-violet color with iodine

19. glycogen

20. 3 Cellulose
• The β-glucose molecules are joined by condensation, i.e. the
removal of water, forming β-(1,4) glycosidic linkages.
• The glucose units are linked into straight chains each 100-1000
units long.

22. Cellulose

23. 4 pectin
Cell wall
polysaccharide