short description of carbohydrates

1. Carbohydrates
ABDULQADOOS KHAN
BS PATHOLOGY KMU
LECTURER AIMS

2. Carbohydrates
Carbohydrates are
• A major source of energy from
our diet.
• Composed of the elements C,
H, and O.
• Also called saccharides, which
means “sugars.”
2
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings

3. Carbohydrates
3
Carbohydrates
• Are produced by photosynthesis in
plants.
• Such as glucose are synthesized in
plants from CO2, H2O, and energy
from the sun.
• Are oxidized in living cells
(respiration) to produce CO2, H2O,
and energy.
Copyright © 2007 by Pearson Education, Inc
Publishing as Benjamin Cummings

4. CARBOHYDRATES
• Carbohydrates are aldehyde or ketone compounds with
multiple(two or more)hydroxyl groups.
• They are polyhydroxylated compounds with atleast three carbon
atoms, with potentially active carbonyl groups which may either
be aldehyde or ketone groups.
• Carbohydrates including sugars are also called
saccharides(saccharide=sugar).

5. CLASSIFICATION OF
CARBOHYDRATES:
• MONOSACCHARIDES
• DISACCHARIDES
• OLIGOSAACHARIDES
• POLISAACHARIDES

6. Monosaccharides
Monosaccharides consist of
• 3 to 6 carbon atoms.
• A carbonyl group (aldehyde or ketone).
• Several hydroxyl groups.
6

7. MONOSACCHARIDES:
• Also called simple sugars ,are those which can not be
hydrolyzed further into simpler forms.
• General formula------------CnH2nOn
• They can be subdivided further ,
• A) Depending upon the number of carbon atoms
they possess ,as trioses,tetroses,pentoses,hexoses,etc.
• B) Depending upon whether aldehyde(-CHO) or
ketone(-CO) groups are present as aldoses or ketoses

8. General formula Aldosugars Ketosugars
Trioses
(C3H6O3)
Glyceraldehydes Dihydroxyacetone
Tetroses
(C4H8O4)
Erythrose Erythrulose
Pentoses
(C5H10O5)
Ribose Ribulose
Hexoses
(C6H12O6)
Glucose Fructose

9. Aldoses
Aldoses are monosaccharides
• With an aldehyde group.
• With many hydroxyl (─OH)
groups.
triose (3 C atoms)
tetrose (4 C atoms)
pentose (5 C atoms)
hexose (6 C atoms)
9
O
║
C─H aldose
│
H─ C─OH
│
H─ C─OH
│
CH2OH
Erythose, an aldotetrose

10. Ketoses
Ketoses are monosaccharides
• With a ketone group.
• With many hydroxyl (─OH)
groups.
triose (3 C atoms)
tetrose (4 C atoms)
pentose (5 C atoms)
hexose (6 C atoms)
10
CH2OH
│
C=O ketose
│
H─ C─OH
│
H─ C─OH
│
H─C─OH
│
CH2OH
Fructose, a ketohexose

11. Trioses

12. Tetrose

13. Different hexoses

14. D-GlucoseD-glucose is
• Found in fruits, corn
syrup, and honey.
• An aldohexose with the
formula C6H12O6.
• Known as blood sugar in
the body.
• Glucose is present in the
form of polymers in
starch, cellulose, and
glycogen.
14
Copyright © 2007 by Pearson Education, Inc
Publishing as Benjamin Cummings

15. D-Fructose
D-fructose
• Is a ketohexose
C6H12O6.
• Is the sweetest
carbohydrate.
• Is found in fruit juices
and honey.
H OH
CH2OH
C
HO
H OH
H
C
O
C
C
CH2OH
D-Fructose
15

16. D-Galactose
D-galactose is
• An aldohexose C6H12O6.
• Obtained from lactose, a
disaccharide.
• A similar structure to glucose
except for the
–OH on C4.
H
H
H OH
CH2OH
C
HO
HO HC
OH
C
C
O
C H
D-Galactose
16

17. PICTURE

18. DISACCHARIDES:
• Are those sugars which yield two molecules of the same
or different molecules of monosaccharide on hydrolysis.
• General formula-----------Cn(H2O)n-1
• Examples:
• Maltose: Yields 2 molecules of glucose on hydrolysis.
• Lactose: Yields one molecule of glucose and one
molecule of galactose on hydrolysis.
• Sucrose: Yields one molecule of glucose and one
molecule of fructose on hydrolysis.

19. Important Disaccharides
A disaccharide
• Consists of two monosaccharide.
Monosaccharide Disaccharide
Glucose + glucose maltose
Glucose + galactose lactose
Glucose + fructose sucrose
19

20. OLIGOSAACHRIDES:
• Are those which yield 3 to 10 monosaccharides units
on hydrolysis, e.g.Maltotriose.
• These are short chain condensation products of two
to ten monosaccharide units or residues joined to
each other covalently through O- glycoside bonds or
linkages.
• Some oligosaccharides are,
• Maltotriose (has three glucose units)

21. Carbohydrates
Polysaccharides
21
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings

23. Mucilages
Glycoconjugates
Glycosaminoglycan
These are polysaccharides contain in
their molecules certain groups in
addition to carbohydrates.

24. BIOMEDICAL IMPORTANCE OF
CARBOHYDRATES:
• Chief source of energy
• Constituents of compound lipids and conjugated
proteins
• Certain carbohydrate derivates are used as drugs like
cardiac glycosides/antibiotics
• Lactose principal sugar of milk—in lactating
mammary glands.
• Degradation products utilized for the synthesis of
other substances such as fatty acids, cholesterol,
amino acids etc.
• Derangement of glucose metabolism is seen in
Diabetic mellitus.