agar

Question 1

Composed of repeating units of

Answer 1

D-galactose & 3,6-anhydro-L-galactose

Question 2

Consist of 2 groups of polysaccharides

Answer 2

• Agarose
• Agaropectin

Question 3

Gelling component Agarose

Answer 3

(due to the absence of sulfate ester groups, which strengthen the hydrophobic character, agar is a good gelling agent that is independent of cation

Question 4

Agarose Structure

Answer 4

Linear, no branching, can form helix (able to
trap water

Question 5

Agaropectin

Answer 5

Non-gelling

Question 6

Solubility and gelation is not affected by

Answer 6

the presence of electrolytes

Question 7

The agar gelation process is

Answer 7

totally reversible. The gel melts
on heating and resets on cooling

Question 8

agar gelation Produce

Answer 8

rigid gel at concentration of ~1%

Question 9

agar Gelation occurs at temperature

Answer 9

far below gel’s melting point

Question 10

Agar does not require

Answer 10

cations to gel

Question 11

At high temperatures, agarose exists as

Answer 11

a disordered ‘random coil

Question 12

after cooling, agarose

Answer 12

Form ordered double-helix state

Question 13

Interaction between helix occurs at the junction zones,

Answer 13

forming a 3D-network that trap and
immobilize water molecule

Question 14

responsible for gelling of agar & agarose

Answer 14

3,6-anhydro-alpha-L-galactose