General Introduction of carbohydrates carbohydrates introduction of carbohydrates, carbohydrates by raj kumar kumawat, carbohydrates introduction for students

2. Carbohydrates
Carbohydrates are
Organic compounds with general formula (CH O) .
The major source of energy from our diet.
Composed of the elements C, H and O.
Also called saccharides, which means “sugars.”
2 n

3. Carbohydrates
Carbohydrates:-
 are produced by photosynthesis in plants.
 such as glucose are synthesized in plants from CO , H O,
and energy from the sun.
 are oxidized in living cells to produce C O , H O, and
energy.
2 2
2 2

4.  Carbohydrates are sugars and provide
energy when consumed.
 Our bodies break down carbohydrates to
extract energy. Carbon dioxide and water are
released in the process.
 Glucose is the primary carbohydrate our
bodies use to produce energy.
 Carbohydrates are classified as biomolecules.

5. Simple carbohydrates are referred to as
simple sugars and are often sweet to the taste.
Consumption of more sugar than is needed for
energy results in conversion of these sugars to
fat.
Complex carbohydrates include starches and
the plant and wood fibers known as cellulose.

6. Examples of isomers:
1. Glucose
2. Fructose
3. Galactose
4. Mannose
Same chemical formula C H O6 12 6
ISOMER : Each of two or more compounds with same
formula but a different arrangement of atoms in the
molecule and different properties.

7. When sugar differ from one another in
configuration at only one (chiral center)
asymmetric atom they are called epimers .
Examples of epimers :
D-glucose & D-galactose (epimeric at C4)
D-glucose & D-mannose (epimeric at C2)

8. CHO
C
C
C
C
CH OH2
H
H
OH
OHH
H
HO
HO
D-Mannose
CHO
C
C
C
C
CH OH2
OH
H
OH
OHH
H
HO
H
D-Glucose
CHO
C
C
C
C
CH OH2
OH
H
H
OHH
HO
HO
H
D-Galactose
C2 EPIMERS C4 EPIMERS
1
2
3
4
5
6

9. ENANTIOMERS
Enantiomers are chiral molecules that are mirror image of
one another and are non-super-imposable on one another.
The two members of the pair are designated as D and L forms.
In D form the OH group on the asymmetric carbon is on the right.
In L form the OH group is on the left side.
E.g.: D-glucose and L-glucose are enantiomers
Chiral molecules with one or more stereo centers can be enantiomers.

10. CHO
C
C
C
C
CH OH2
OH
H
OH
OHH
H
H
D-Glucose
HO
CHO
C
C
C
C
CH OH2
L-Glucose
H
H
H
OH
HO
H
HO
HO

11. CLASSIFICATION OF CARBOHYDRATES
1. Monosaccharide are the simplest carbohydrates. They cannot be broken down
to smaller carbohydrates. E.g. Glucose, Fructose, Mannose, Galactose
2. Disaccharides consist of two monosaccharide units joined together; they can be
split into two monosaccharides. E.g. Sucrose, Maltose
3. Oligosaccharides consists of three to nine monosaccharide units. E.g.
Raffinose
4. Polysaccharides are large molecules containing 10 or more monosaccharide
units. Polysaccharides further divided into two groups:
a. Homopolysaccharides (all 1 type of monomer) E.g. Glycogen, Starch, Cellulose,
Chitin
b. Heteropolysaccharides (different types of monomers) E.g. Peptidoglycans,
Glycosaminoglycans

12. MONOSACCHARIDES
Glucose is the most abundant monosaccharide found in nature. Glucose is
also known as dextrose, blood sugar, and grape sugar. Glucose is broken
down in cells to produce energy.
Galactose is found combined with glucose in the disaccharide lactose,
which is present in milk and other dairy products.
Mannose, a monosaccharide, is found in some fruits and
vegetables.Cranberries contain high amounts of mannose, which has been
shown to be effective in urinary tract infections. Mannose is an epimer of
glucose.
Fructose, a ketose, is commonly referred to as fruit sugar or levulose.
Fructose is the sweetest monosaccharide and is found in fruits, vegetables,
and honey.

13. DISACCHARIDES
Maltose is known as malt sugar. It is formed by the breakdown of starch. Malted
barley, a key ingredient in beer, contains high levels of maltose. One of the
anomeric carbons is free, so maltose is a reducing sugar. The glycosidic bond is
α(1→4).
Lactose is known as milk sugar. It is found in milk and milk products.The
glycosidic bond is (1→4). One of the anomeric carbons is free, so lactose is a
reducing sugar.
Sucrose is known as table sugar. It is the most abundant disaccharide found in
nature. Sucrose is found in sugar cane and sugar beets. The glycosidic bond is 
(1→2). Both anomeric carbons of the monosaccharides in sucrose are bonded,
therefore, sucrose is not a reducing sugar. It will not react with Benedict’s reagent.

14. POLYSACCHARIDES
Starch is a mixture of amylose and amylopectin and is found in plant foods.
Amylose makes up 20% of plant starch and is made up of 250–4000 D-glucose units
bonded α(1→4) in a continuous chain. Amylopectin makes up 80% of plant starch
and is made up of D-glucose units connected by α(1→4) glycosidic bonds. About
every 25 glucose units of amylopectin, a branch of glucose units are connected to
the glucose by an α(1→6) glycosidic bond. During fruit ripening, starch undergoes
hydrolysis of the α(1→4) bonds to produce glucose and maltose, which are sweet.
When we consume starch, our digestive system breaks it down into glucose units for
use by our bodies.
Glycogen is the polysaccharide that is similar to amylopectin, but is more highly
branched. Glycogen is a storage polysaccharide found in animals. Glycogen is stored
in the liver and muscles. Its structure is identical to amylopectin, except that α(1→6)
branching occurs about every12glucose units. When glucose is needed, glycogen is
hydrolyzed in the liver to glucose.

15. POLYSACCHARIDES
Cellulose contains glucose units bonded (1→4). This glycosidic bond configuration
changes the three-dimensional shape of cellulose compared with that of amylose. The
chain of glucose units is straight. This allows chains to align next to each other to form a
strong rigid structure. This is mainly found in cell walls of plants.
Chitin: (1→4) linked N- acetyl glucosamine residues. This is found in the hard
exoskeletons (shells) of arthropods (e.g., insects, lobsters and crabs).
ABO blood types refer to carbohydrates on red blood cells.These chemical markers are
oligosaccharides that contain either three or four sugar units. Sugar units are D-galactose,
L-fucose, N-acetyl glucosamine, and N-acetyl galactosamine.
Heparin is a medically important polysaccharide because it prevents clotting in the
bloodstream. It is a highly ionic polysaccharide of repeating disaccharide units of an
oxidized. monosaccharide and D-glucosamine. Heparin also contains sulfate groups that
are negatively charged. It belongs to a group of polysaccharides called
glycosaminoglycans.

16. ROLE OF CARBOHYDRATES
An immediate source of energy for the living cell.
Have a protein sparing action.
Involved in the breakdown of fatty acids and
preventing ketosis.
Major dietary fiber (cellulose).
Used as flavouring agents.
Used as sweetening agents.
Regulates metabolic process in the body.
Stored forms of energy.
Provides protection of bacterial cell wall.
Pentose sugars (ribose & deoxyribose) form an
important component of nucleic acids.
Heparin functions as a physiological anticoagulants.

17. ROLE OF CARBOHYDRATES
Sucrose is used for the preparation of simple syrup.
Used as a diluents and as a binders in tablets.
Liquid glucose used in sugar coating.
Used for the preparation of infant’s food.
Used for the preparation of sterile i.v. solution.
Used as anti-diarrheal drugs (Pectin).
Used as a laxative (Mucilage, lactulose).
Used as an antacid (sucralfate).
Used as diuretics (Sorbitol, Manitol).
Used as nutrient media for both bacteria & tissue
culture (Agar).
Used as an emulsifying agent(Gums).
Used in the preparation of surgical dressings
(Cellulose) and plasters(Gums).