Carbohydrates are the most abundant biomolecules on Earth. They function as organic matter, energy stores, structural components, and in industries. Carbohydrates are classified as monosaccharides, oligosaccharides, or polysaccharides. Monosaccharides include aldoses and ketoses ranging from trioses to heptoses. Fischer and Haworth projections are used to represent monosaccharide structures. Oligosaccharides contain 2-10 monosaccharide units and include disaccharides like sucrose, maltose, lactose, and trehalose. Polysaccharides are polymers of monosaccharides that can be classified as storage polysaccharides like starch and glycogen or structural polysaccharides.

1. CARBOHYDRATES
HIMA HARIDASAN

2. INTRODUCTION
 Most abundant biomolecule on earth
 Def : polyhydroxy aldehydes or ketones
 G.F. : (CH2O) n
Composition : C: H :O – 1:2:1

3. FUNCTIONS
 Organic matter
 Energy stores, fuels, & metabolic intermediates
 Ribose & deoxyribose
 Structural components
 Glycolipids &glycoproteins
 Industries
 Excess Fat
 Can’t be further hydrolysed

4. CLASSIFICATION
SIMPLE COMPLEX
MONOSACCHARIDES
OLIGOSSACHARIDES
POLYSACCHARIDES
ALDOSE
KETOSE
TRIOSE
TETROSE
PENTOSE
HEXOSE
HEPTOSE
•1 / 2 monomeric
units
•Sweet
•Monomer
polymer
•Starchy

5. MONOSACCHARIDES
Mono = 1
Single polyhydroxy aldehyde or
ketone.
Literally- C hydrate
Colorless
Crystalline
Solubility – H2O

6. NO.OF
C
ATOMS
CLASSES ALDOSE KETOSE
3 Triose Glyceraldehyde Dihydroxyacetone
4 Tetrose Erythrose Erythrulose
5 Pentose Ribose Ribulose
6 Hexose Glucose Fructose
7 Heptose Glucoheptose Sedoheptose

7. FISCHER’S PROJECTION
 Herman Emil Fischer
 2D representation of a 3D organic molecule by projection
 Bonds :-
Horizontal - viewers
Vertical - viewers
 Use : to differentiate btw L- and D- molecules

8. Features:-
 Can’t be rotated by 90° or 270° in the plane of the
page or the screen, as the orientation of bonds
relative to one another can change, converting a
molecule to its enantiomer.
 Rotation of 180° doesn't change the molecule's
representation.
( Enantiomer: one of two stereoisomers that
are mirror images of each other; non-superposable)

9. HAWORTH PROJECTION
 Syn: Norman projection; pyranose projection
 Sir Norman Haworth
 In aqs soln.
 Cyclic/ring structure of monosaccharide
 3D

10.  Result of: general reaction btw aldehydes or ketones
with alcohols to form derivatives called hemiacetals
or hemiketals.

11. Characteristics:_
 C - implicit type; C1- anomeric carbon.
 H - implicit
 Thicker/Thinner line indicates atoms that are closer/far
to the observer.
 The groups below the plane of the ring in Haworth
projections = groups on the right-hand side of a Fischer
projection.

12. GLYCERALDEHYDE

13. FISCHER’S
PROJECTION
HAWORTH
PROJECTION
GLUCOSE

14. D- FRUCTOSE
FISCHER’S PROJECTION HAWORTH PROJECTION

15. D-MANNOSE
FISCHER’S PROJECTION HAWORTH PROJECTION

16. D- GALACTOSE
FISCHER’S PROJECTION HAWORTH PROJECTION

17. OLIGOSACCHARIDES
 2-10 monosaccharide units linked by glycosidic linkage
 Oligo = a few
 Associated with:-
1) Proteins - glycoproteins
2) Lipids - glycolipids
 Varities seen more in plant kingdom than animal
kingdom
 Most abuntant- dissacharides

18. OLIGOSACCHARIDE CLASSIFICATION BASED
ON THE NO.OF MONOMERIC UNITS
CLASS
NO.OF
MONOMERS EXAMPLES
DISACCHARIDE 2 LACTOSE
TRISACCHARIDE 3 RAFFINOSE
TETRASACCHARIDE 4 STACHYOSE
PENTASACCHARIDE 5 VERBASCOSE

19. DISACCHARIDES
Syn: biose
 2 monosaccharides covalently linked
 Linkage – glycosidic
 Result of - condensation reaction (the
elimination of a small molecule, like H2O,
from the functional groups only)
 Solubility - H2O

20. DISACCHARIDES
REDUCING
MALTOSE
ISOMALTOSE
LACTOSE
CELLOBIOSE
NON-REDUCING
SUCROSE
TREHALOSE

21. SUCROSE
 Syn: cane sugar
 Sweetning agent
 Source: cane & beet sugar, pineapple,sorghum, carrot
 Designation: α-D-glucopyranosido-β-D-fructofuranoside
 Found as such in most photosynthetic plant
 Sucrose deficiency- malabsorption leads to diarrhea &
flatulence
 D.E: sucrase or invertase

22. Sucrase Action:-

23. TREHALOSE
 Dsgn: 1-(α -D-glucopyranosido)- α -D-glucopyranoside
 Source: ocoon of Trehela, hemolymph of some insects &
fungi including yeast
 Sweetning agent
 D.E.: trehalase
Trehalose Trehalase
2-D-Glucose

24. MALTOSE
 Syn: malt sugar
 Designation: 4-(α -D-glucopyranosido)-D-glucopyranose
 Doesn’t occur naturally
 Usually obtained in β form
 Source: starch hydrolysis, germinating cereals, malt
 Intermediate of starch
 D.E.: Maltase

26. LACTOSE
Syn: milk sugar
 Reducing
 Designation: 4-(β -D-galactopyranosido)-
D-glucopyranose
Usually obtained in β form
 Constitute 5% in milk
 Exclusive cbh source for breast fed infants

27.  D.E: lactase
 Lactase action:-
 Lactose intolerance: lactase deficiency
leads to diarrhea & flatulence

28. CELLOBIOSE
 Formed on cellulose degradation
 On hydrolysis gives β -D-glucose
 Dsgn: 4-(β -D-glucopyranosido)-D-glucopyranose
 Source: enzymatic or acidic hydrolysis of cellulose and
cellulose rich materials such as cotton, jute, or paper.
ISOMALTOSE
 Dsgn: 6-(α -D-glucopyranosido)-D-glucopyranose
 Produced when high maltose syrup is treated with the
enzyme transglucosidase

30. POLYSACCHARIDE
 Poly = many
 >10 monosaccharide units
 Syn: glycans
 Classification – different ways on the basis of:-
1. Structure : linear & branched
2. Homogenity btw monomers: homo & hetero
3. Function: muco, storage & structural
 Linear polysaccharides: line/ chain. Eg- cellulose.
 Branched polysaccharides: linear chains with units arising
from different C atoms, branched. Eg- starch, glycogen.

31.  Storage polysaccharides:-
1. acts as reserve food
2. Hydrolysed to sugars required for respiration &
biosynthesis
3. Eg- starch, glycogen, inulin.
4. Syn: nutrient polysaccharides
 Structural polysaccharides:-
1. Fibrous
2. Cell walls of plants, fungi, & exoskeleton of arthropods

32. Mucopolysaccharides
1. Syn: GAG
2. Heteroglycans
3. Slime & mucilage producing.
4. Composition- repeating units of sugar derivatives
namely, amino sugars & uronic acids.
5. General groups present- acetylated amino groups,
sulphate & carbonyl groups
6. Acid mucopolysaccharides - Sulphate & carbonyl
groups contributes to acidity
7. Eg- heparin, hyalouronic acid

33.  Homopolysaccharide
1. Homoglycans
2. Eg- Starch, glycogen,cellulose,chitin,xylan
 Heteropolysaccharide
1. Heteroglycans
2. Monomers- non-identical
3. Complex
4. Eg: hyaluronic acids, heparin, agar, chondroitin
sulphate, keratan sulphate, dermatan sulphate, gum
arabic, pectin & so more.

34. STARCH
 Syn: amylum
 Widely distributed in plant kingdom
 Components- amylose & amylopectin
 D.E.:-
1. Amylase - maltose, glucose; Site of action- α(1 4) glycosidic bonds
2. Sucrase – G & F; α(1 4) glycosidic bonds
3. Α-glucosidase- removes 1 unit at a time from oligosaccharide
4. Α-dextrinase – debranching enzyme; α (1 4) & α(1 6) .

35. FEATURE AMYLOSE AMYLOPECTIN
Content in starch 15% - 20% 80% - 85%
Branching Absent Present [α(1,6) g.l. at brancing
points]
Linkage α-1,4 α-1,4 ; α-1,6
No.of G units 200-1000 20-30
Water solubility Present Absent
Color reaction with
iodine gives
Blue Reddish-violet

36. CH2OH
CH2OH
H
OH
H O
OH
H
H
OH
H OH
CH2
CH2OH
H
OH
H H O H
H O
H
CH2OH
H
OH
H OH
O
O
H
H
OH
H OH
CH2OH
CH2OH
H H O
H O H
H
H
OH
H OH
OH
O
H
H
OH
H OH
O
H
O
1 4
6
H O
H
H OH
H H O
H
H OH
H
O
1
OH
3
4
5
2
amylopectin

37. GLYCOGEN
 Animal starch
 Stored in liver & muscles
 Source- plants that lack chlorophyll, yeast, fungi, etc.
 D.E. : glycogen phosphorylaseand amylase
 Monomers- α & β G units; (1,4)g.l.
 Glycogenolysis
 With I2 – red
 Branching occurs after 12 G units

38. CH2OH
CH2OH
H
OH
H O
OH
H
H
OH
H OH
CH2
CH2OH
H
OH
H H O H
H O
H
CH2OH
H
OH
H OH
O
O
H
H
OH
H OH
CH2OH
CH2OH
H O H
H H O
H
H
OH
H OH
OH
O
H
H
OH
H OH
O
H
O
1 4
6
H O
H
H OH
H H O
H
H OH
H
O
1
OH
3
4
5
2
glycogen