Carbohydrates for mbbs course. Learn from the best materials. Pick up and take subscription. Get the best. Carbohydrate structure. Carbohydrates function. Learn from the best. Be a good doctor. Libe the life of a good doctor. Carbohydrates structure and function.

1. Quick fire

3. Specific Learning Objective
Classify Polysaccharides and provide examples.
Explain structure function of glycogen, starch and
cellulose.
Define Dietary fibers.
Explain the benefits and functions of Dietary fiber.

4. O- Glycosidic
OO
H
O
H
C C
C
C O
C
H
O
H
O
H
O
H
O
H
H
H
CH2
OH
H
H
CH2
OH
C C
C
C O
C
H
O
H
O
H
O
H
O
H
H
H
CH2
OH
H
H
C C
C
C O
C
H
O
H
O
H
O
H
H
H
CH2
OH
H
H
C C
C
C O
C
H
O
H
O
H
O
H
H
H
CH2
OH
H
H
O
H H
Glycosidic
Bond
This is a CONDENSATION
reaction, where a water
molecule is lost.
Glucose
Maltose

5. Polysaccharides

6. Polysaccharides

7. Starch
❑Storage homopolysaccharide.
❑Consist of two types of polymers called amylose and
amylopectin
Amylose
•linear polymer of D glucose
•α1 4 linkages

8. Amylopectin
•Amylopectin has (α1 6) branch points
•Branch points occur about every 24 to 30 residues.
▪Glucose residues at the nonreducing ends of the outer
branches are removed enzymatically.

9. Glycogen
•Main storage polysaccharide
•D glucose units are (α1 4) and the linkages at
branch points are (α1 6)
•Branch points occur more frequently in glycogen
(about every 8 to 12 residues) than in amylopectin
•Abundant in hepatocytes

10. Cellulose
▪linear homopolysaccharide.
▪D glucose units held together in (ß1 4) linkages.
▪cellulose can contain 10-to-15,000 residues.
▪Due to the presence of ß linkages, cellulose chains
fold quite differently than chains of D glucose in the
starches and glycogen.
▪Insoluble in water.
▪Vertebrate animals lack the hydrolytic enzymes
(cellulases).

11. chitin
❑Chitin is a linear
homopolysaccharide composed
of N-acetylglucosamine
residues in (ß1 4) linkage.
❑Difference from cellulose by
replacement of the hydroxyl
group at C-2 with an acetylated
amino group.

13. Heteropolysaccharides
Mucopolysaccharides (Glycosaminoglycans)
linear polymers composed of repeating disaccharide units.
N-acetylglucosamine or N-acetylgalactosamine.
Uronic acid, usually D-glucuronic acid or its 5-epimer,
L-iduronic acid.
Some GAGs contain sulfate groups attached to hydroxyl
groups in ester linkage.
Very high density of negative charge.
sulfated glycosaminoglycans are attached to extracellular
proteins to form the proteoglycans.

14. Hyaluronic acid
▪consists of alternating
residues of
D-glucuronic acid and
N-acetylglucosamine.
▪A single molecule contains up to 50,000 repeats.
▪lubricant in the synovial fluid.
▪vitreous humor of the eye.
▪component of the ECM of cartilage and tendons

15. Chondroitin sulfate
Much shorter polymers
Covalently linked to specific
proteins forming proteoglycans.
One or both monomeric units
differ from those of Hyaluronic.
❑D-glucuronic acid and sulfated N-acetylgalactosamine
units.
❑It contributes to the tensile strength of cartilage,
tendons, ligaments, and the wall of the aorta.

16. Keratin sulfates
❑lack uronic acid and their
sulfate content is variable.
❑D-galactose and sulfated N-acetylglucosamine residues.
❑Present in the cornea, cartilage, bone, and a variety of
horny structures formed of dead cells: horn, hair, hoofs,
nails, and claws.

17. Heparan sulfate
❑variable arrangements of
sulfated and nonsulfated sugars.
❑sulfated L-iduronate and sulfated
N-acetylglucosamine residues.
❑sulfated segments allow large interactions.
❑Heparin is a fractionated form of heparan sulfate that is a
therapeutic agent used to inhibit blood coagulation.

18. Mucopolysaccharides

19. Proteoglycans

20. Glycoproteins

21. Lectins

23. Dietary fibers

24. Functional Fibers

25. Dietary fibers

26. Soluble fibers

27. Bulk

28. Insoluble fibers

29. How much dietary fiber do I require?

30. Fiber reduces insulin spike

31. Bile acid Sequestrant

33. Resistant Starch

37. Summary

38. ◆ Diagnosis: Irritable bowel syndrome.
◆Biochemical mechanism: Cellulose-containing foods are not
digestible but swell up by absorbing water and correlate with larger
softer stools. The increase in dietary fiber also increases the intestinal
transit time and decreases the intracolic pressure, thereby decreasing
the symptoms of irritable bowel.