This document provides an overview of carbohydrates. It begins by defining carbohydrates and providing their general formula. It then classifies carbohydrates into monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides are further classified based on functional groups and number of carbon atoms. The structures of monosaccharides and examples of different types of polysaccharides are also outlined. The document discusses optical isomerism in sugars and provides examples of chemical reactions and qualitative tests used to identify carbohydrates. It concludes by covering the biological importance of carbohydrates and some diseases related to carbohydrate metabolism such as diabetes, glycosuria, and glycogen storage diseases.

1. KAMLA NEHRU COLLEGE OF
PHARMACY
BUTIBORI, NAGPUR-441108
Carbohydrate
s
Presented By
Ms. Monika P. Maske
Assistant Professor
M. P:harm
(Pharmaceutical Chemistry)

2. INTRODUCTION
• Carbohydrates are defined as polyhydroxy aldehydes or ketones, or compounds
and their derivatives which on hydrolysis yield their monomer or polyhydric
alcohol.
• The general formula of carbohydrate is Cn(H2O)n. Where, n=no. of Carbon atoms.
• Carbohydrates supply major part of energy needed by the living cell.

3. CLASSIFICATION OF CARBOHYDRATES

4. 1. Monosaccharides : Carbohydrates that cannot be hydrolysed to simple
compounds are called monosaccharides.
a) Classification on the basis of functional group:
(1) Aldoses- When monosaccharides contain aldehydic functional grp., they
termed as aldoses. Ex. Glucose
(2) Ketoses- When functional grp. Present in monosaccharide is keto grp.
they called as ketoses. Ex. Fructose

5. b) Classification on the basis of number of carbon atoms:
i. Trioses- Contain 3 carbon atoms. Ex: Glyceraldehyde.
ii. Tetroses- Contain 4 carbon atoms. Ex. Erythrose, threose.
iii. Pentoses- Contain 5 carbon atoms. Ex. Ribose, arabinose, xylose.
iv. Hexoses- Contain 6 carbon atoms. Ex. Glucose, fructose, galactose,
mannose.
v. Heptoses- Contain 7 carbon atoms. Ex. Glucoheptose.

6. STRUCTURES OF MONOSACCHARIDES

7. II. Disaccharides : Carbohydrates that give two monomeric units on hydrolysis, are
called disaccharides. Ex. Maltose, sucrose, lactose.

8. III. Oligosaccharides : Carbohydrates that give three to ten monosaccharides on
hydrolysis are called oligosaccharides. Ex. Raffinose, maltotriose.

9. IV. Polysaccharides : Carbohydrates give many monosaccharides on hydrolysis
are called polysaccharides.
- It made up of one or different types of sugars.
- All monomeric units are linked to each other via glycosidic linkage.
- These are of complex carbohydrates of high mol. wt.
- Quite insoluble in water, when soluble, forming colloidal solutions.
- On hydrolysis it gives simple sugars.

10. - These are further classified into 2 types based on their composition.
a) Homopolysaccharides – Polysaccharides on hydrolysis give only one
type of monosaccharide are called homopolysaccharides. Ex. Starch,
glycogen, cellulose, dextrin.
b) Heteropolysaccharides - Polysaccharides on hydrolysis give two or
many types of monomers are called heteropolysaccharides. Ex. Agar,
heparin, alginic acid, hemicellulose.

11. OPTICAL ISOMERISM / OPTICAL ACTIVITY
• Sugars are optically active, because sugar molecules contain asymmetric C
atom.
• Carbon atom can have 4 grp. Attached to it, if all these 4 grp. Are different, then C
atom will possess asymmetry.
• C atom is said to be asymmetric when its mirror images are non-superimposable
on each other. These type of compounds called as enantiomeric pair.

12. • Enantiomers have identical physical properties but they interact
differently with polarized light.
• These compounds have tendency to rotate plane of polarized light,
called optically active.
• If plane of polarized light is rotated in clockwise direction, then it is
called dextro rotatory, when rotated in anticlockwise direction, then
its called leavo rotatory.

13. • For given enantiomeric pair, both rotate the plane of polarized light to same extent
but in the opposite direction.
• The optical rotation is measured by an instrument called polarimeter.
• Instrument designed especially for examination of sugar solutions is called as
saccharimeter.

14. • Specific rotation for a given sugar is calculated by,

15. • Mutarotation : When isomers of same sugar are dissolved in water, the optical
rotation of each gradually changes with time and tends to final equilibrium value
called as mutarotation.
• Ex.
-
D-Glucose D-Glucose β-D-Glucose
(+112.20) (-52.50) (+18.70)
Equilibrium value

16. CHEMICAL REACTIONS & QUALITATIVE TESTS
1) Dehydration: carbohydrates on dehydration give furfural or its derivatives.
- Conc. Sulphuric acid used as dehydrating agent.
ex.
Molisch test: It is general test for carbohydrates identification.
- carbohydrates + alpha-naphthol Violet colour.

17. II. Reactions of carbonyl group: reducing properties- Carbohydrates having free
or potential carbonyl function act as reducing agents, such sugars called as
reducing sugars.
a. Benedict's test- carbohydrates + heat + alkaline copper sulphate red
ppt. this test for reducing sugar(like sucrose).
b. Barford's test- carbohydrates + heat + acidic condition red ppt. this
test for reducing monosaccharides.
c. Fehling's test- carbohydrates + heat + Fehling's reagent red ppt. it
reduced the copper ions.

18. d. Formation of Osazone: when reducing sugar is heated with phenylhydrazin
gives yellow crystalline compounds called osazone are formed.

19. III. Reduction: The carbonyl grp. Of sugar can be reduced by variety of reagents
such as hydrogen and platinum to an alcohol.
Glucose H2-Pt Sorbitol
IV. Oxidation: Sugars on oxidation gives acid.
- The oxidation product depends upon oxidating agents used in the
reaction.
V. Mucic acid test: Test is used for identification of galactose and lactose.
- Galactose, lactose on oxidation in the presence of conc. nitric
acid it gives galactosaccharic acid (mucic acid) i.e. colourless liquid.

20. VI. Iodine test: iodine reacts with starch, dextrin and glycogen to forma coloured
complex.
Table: Iodine test for polysaccharides
Type of polysaccharide Colour with iodine
1. Starch Blue
2. Dextrin Brown
3. Glycogen Pink
4. Amylose Deep blue
5. Amylopectin Purple

21. BIOLOGICAL IMPORTANCE OF
CARBOHYDRATES
o Carbohydrates are important constituents of cell str. In the form of glycoprotein,
heparin, starch, cellulose.
o It is important source of energy and stores the energy.
o It is important basic material for organic compounds like lipids, nucleic acid,
amino acids.
o It is important raw material for industrial production of products like glucose,
maltose, alcohol, acids.

22. DISEASES RELATED CARBOHYDRATES
1. Diabetes mellitus: It is group of metabolic disorders with characteristics of
hyperglycaemia.
- Hyperglycaemia in DM is due to defect in insulin action. DM is broadly classified
into 2 categories:
a) Type I Diabetes- It is characterized by absolute deficiency of insulin due to
destruction of beta –cells of pancreas.
b) Type II Diabetes- It caused due to high secretion of insulin by beta cells of
pancreas.
- Symptoms are polyuria, polydipsia and polyphagia.

23. 2. Glycosuria: When glucose is excreted in urine, the condition called as
glycosuria.
- It occurs due to elevated blood glucose levels.
3. Galactosemia: It due to deficiency of enzyme galactose cannot be converted
into glucose condition called as galactosemia.
- It increases the level of galactose in urine and circulation.
- symptoms are jaundice, mental retardation.

24. 4. Fructose- intolerance: Normal sugar of fruits(i.e fructose) get normally
metabolised to give energy and CO2.
- But in this condition defective metabolism develop high conc.
Of sugar in blood, this called as fructose-intolerance.
5. Glycogen storage disease: The metabolic abnormalities related with glycogen
synthesis and degradation are collectively termed as glycogen storage disease.

25. THANK YOU