Introduction to Biotechnology

INTRODUCTION TO

BIOTECHNOLOGY

II. MACROMOLECULES

B. MOLECULAR STRUCTURE OF

LIVING MATTER:











POLYSACCHARIDES

LIPIDS

NUCLEIC ACID

AMINO ACIDS AND PEPTIDE BONDS

PROTEINS: STRUCTURE AND

FUNCTION

POLYSACCHARIDE

 Two types of polysaccharide

1. Homo-polysaccharide - have only one type of

monosaccharide repeating in the chain

2. Hetero-polysaccharide - composed of two or

more types of monosaccharides

POLYSACCHARIDE

 homo-polysaccharides can be branched

or unbranched as long as they all have

the same monosaccharide unit

POLYSACCHARIDE

 the different colors represent different

monosaccharides

POLYSACCHARIDE

STARCH

POLYSACCHARIDE

STARCH

 Starch is a storage compound in plants,

and made of glucose units

 It is a homo-polysaccharide made up of

two components: amylose and

amylopectin.

 Most starch is 10-30% amylose and 7090% amylopectin

POLYSACCHARIDE

AMYLOSE

o a straight chain structure formed by 1,4

glycosidic bonds between α-D-glucose

molecules.

Structure of Amylose Fraction of Starch

an α-1,4’-glycosidic linkage

6CH OH

CH2OH

H

O

H

OH

H

H

H 1

5

O

H

4 OH

OH

O

H

OH

H

H H

H

O

O

3

H

H

H 1

O

OH

H

CH2OH

CH2OH

CH2OH

2

O

H

OH

H

H H

O

H

OH

H

O

OH

2

OH

H

OH

amylose

H

OH

H

H

OH

POLYSACCHARIDE

AMYLOSE

•The amylose chain forms

a helix.

•This causes the blue

colour change on reaction

with iodine.

•Amylose is poorly soluble

in water, but forms

micellar suspensions

POLYSACCHARIDE

AMYLOPECTIN

 a glucose polymer with mainly α -1,4’glycosidic linkages, but it also has

branches formed by α -1,6’ linkages.

Branches are generally longer than

shown above.

Structure of Amylopectin Fraction of Starch

an α-1,6’ linkage

CH 2 O H

CH 2 O H

O

H

H

OH

H

H

H

OH

C H 2O H

H

H

OH

C H 2O H

O

H

OH

H

OH

O

OH

H...