struktur karbohidrat

Ah! sweet mystery of life . . .

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STRUKTUR DAN FUNGSI KARBOHIDRAT

Copyright © 2007 by Heli Siti HMBIOKIMIA1-2007

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Tiga Area Utama Biokimia

Struktur & fungsiBiomolekul

Metabolisme & Bioenergitika

Aliran Informasi Genetik

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BIOMOLEKUL

Karbohidrat Protein Lipid Asam nukleat

Asamamino

Asamlemak

MononukleotidaMonosakarida

Ikatanpeptida

Gaya van der Walls danikatan hidrogen

Ikatanglikosidik

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Siklus karbon

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Carbohydrate and sugar structure

Carbohydrates or saccharides are essential components of living organisms.

(C•H2O)n Where n=3 or greater.

A single saccharide is called a monosaccharide.

Oligosaccharide is a few linked monosaccharides and are at time associated with proteins (glycoproteins) or lipids (glycolipids)

Polysaccharides consist of many monosaccharides i.e. cellulose or glycogen

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Monosaccharides (D-aldoses)

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The Fischer convention, the basis for the D-configuration in sugars comes from D-glyceraldhyde’sconfiguration around its asymmetric carbon.

CHO

OHH

HHO

OHH

OHH

CH2OH

CHO

OHH

HHO

OHH

HHO

CH2OH

D-glucose L-glucose

1

2

3

4

5

6

1

2

3

4

5

6

Epimers differ in configuration around one carbon atom i.e. D-glucose and D-mannose but D-glactose and D-glucose are not epimers because they very around two carbon atoms. There are 2n-2

stereoisomers

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Carbohydrates are classified as to the nature of the carbonyl group : ketone = ketose aldehyde = aldose

Triose

Tetrose

Pentose

Hexose

2(n-3)

stereoisomers of ketoses

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Monosaccharides can form ring structures

O O

PyranFuran

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Glycosidic binds are between two sugars

They can either be in the α or β configuration and can be linked through the 1-2, 1-4 or 1-6 linkage

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Sugar Polymers The Polysacchrides

• Energy Storage– Starch α-amylose and amypectin

• Structural– Cellulose and Chitin

• Glycosaminoglycans• Proteoglycans

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α-amylose

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Cellulose (polyglucose)

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Glycosaminoglycans & Proteoglycans

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Distribusi biomolekul di dalam sel

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