1. CARBOHYDARTE II Done By :Nisreen Moh’d

2. Polysaccharides
Cellulose: the major structural component of plants, especially wood and plant fibers
a linear polymer of approximately 2800 D-glucose units per molecule joined by b-1,4-glycosidic bonds
fully extended conformation with alternating 180° flips of glucose units
extensive intra- and intermolecular hydrogen bonding between chains

3. Cellulose can’t be digested by humans because their cells don’t have the needed enzymes to break B-1,4 glycosidic linkages

4. Starch
A polymers of a-D-glucose units and used for energy storage in plants, 2 forms
amylose: continuous, helical unbranched chains of up to 4000 a-D-glucose units joined by -1,4-glycosidic bonds
amylopectin: a highly branched helical polymer consisting of units of D-glucose joined by
_1,4-glycosidic bonds and branches created by
-1,6-glycosidic bonds
amylases catalyze hydrolysis of -1,4-glycosidic bonds
debranching enzymes catalyze the hydrolysis of

5. Starch

6. Starch: storing form of carbs in plants
Has Straight & branched chains
All monosacharrides are reducing sugar
Percentages of carbs in human diet:
60% starch
30% sucrose
10% lactose

7. Polysaccharides Branching in amylopectin and glycogen
The difference between amylopectin and glycogen is no. of branches
Glycogen every 10
Amylopectin every 25

8. Glycogen : storage form of glucose in animals
Glycogen is stored in liver & muscles
Why glycogen is highly branched ??
-for quick hydrolysis and synthesis
Why glycogen has globular form ??
-decreasing the needed space for storage ; if it were in fibers form for example it would take too much space for small amount
To hydrolyze 1 gram of glycogen the body need to boil 2.5 gram of water

9. Polysaccharides
Chitin: the major structural component of the exoskeletons of invertebrates, such as insects and crustaceans; also occurs in cell walls of algae, fungi, and yeasts
composed of units of N-acetyl--D-glucosamine joined by -1,4-glycosidic bonds

11. Not soluble in water
Similar structure to keratin that is found in hair &nails
It is homopolysaccaride or heteropolysaccaride ??
-it is a homopolysaccaried because it consists of the same repeated unit of which is N-acetyl--D-glucosamine

12. Polysaccharides
Bacterial cell walls: prokaryotic cell walls are constructed on the framework of the repeating unit NAM-NAG joined by b-1,4-glycosidic bonds

13. Bacterial Cell Walls The N-acetyl-D-glucoseamine and
N-acetylmuramic acid polysaccharide is in turn cross-linked by small peptides
in Staphylococcus aureus, the cross link is a tetrapeptide
this tetrapeptide is unusual in that it contains two amino acids of the D-series, namely D-Ala and D-Gln
each tetrapeptide is cross linked to an adjacent tetrapeptide by a pentapeptide of five glycine units
Peptidoglycan: is the resulted cross linking of polysaccharides by peptides

14. Bacterial Cell Walls

15. Bacterial cell wall is heteropolysaccaride consisting of 2 units:
NAM & NAG
NAM is coming from muramic acid that contains 9 atoms of carbon

16. Bacterial Cell Walls The Peptidoglycan of a bacterial cell wall
Staphylococcus
aureus

17. خريطة مفتاحية NAM جزيء NAGجزيء خمس جزيئات من الحمض الأميني غلايسين
مركب رباعي الببتيد أي انه يتكون من اربعة احماض امينية اثنان منهما هما ألانين و غلوتامين
NAM جزيء
NAGجزيء

18. Polysaccharides
Glycosaminoglycans: polysaccharides based on a repeating disaccharide where one of the monomers is an amino sugar and the other has a negative charge due to acid such as a sulfate or carboxylate group
heparin: natural anticoagulant
hyaluronic acid: a component of the vitreous humor of the eye and the lubricating fluid of joints
chondroitin sulfate and keratan sulfate: components of connective tissue

19. The repeating unit of heparin

20. The repeating unit of hyaluronic acid

21. Chondroitin sulfate
The repeating unit of chondroitin sulfate

22. ANTICOAGULANT >>> مادة تمنع تجلط الدم
Remember that NAG is found in :
1))chitin
2))bacterial cell wall
3))hyaluronic acid

23. Glycoproteins antibodies are glycoproteins
Glycoproteins contain carbohydrate units covalently bonded to a polypeptide chain
antibodies are glycoproteins
carbohydrates play a role as antigenic determinants, the portions of the antigenic molecule that antibodies recognize and to which they bond.

24. Glycoproteins : بروتينات تحمل جزيئات كاربوهيدرات
Carbs that are found in the surface of the cell membrane serve as recognition sites
the foreign bodies unit with the carb in the surface of cells which is a sign for the immune system that those cells are abnormal and there is something wrong !After this sign the immune system (WBC’s&macrophages) begins it’s work
Autoimmune disease : disability of the body to differ between it’s normal and abnormal cells

25. Blood Group Substances
Membranes of animal plasma cells have large numbers of relatively small carbohydrates bound to them:
these membrane-bound carbohydrates act as antigenic determinants
among the first antigenic determinants discovered were the blood group substances
in the ABO system, individuals are classified according to four blood types: A, B, AB, and O
at the cellular level, the biochemical basis for this classification is a group of relatively small membrane-bound carbohydrates

26. ABO Blood Classification

27. ABO Blood Classification
in type A, the nonreducing end is NAGal
in type B it is Gal
in type AB, both types are present
in Type O, neither of these terminal residues is present

28. AB : universal receiving
O : universal donor O
B A AB

29. End
Chapter 16