2.2.5 Starch & Glycogen

Question 1

What are polysaccharides?

Answer 1

Macromolecules that are polymers formed by many monosaccharides joined by a glycosidic bond in a condensation reaction to form chains

Question 2

How are the chains in polysaccharides?

Answer 2

1.Branched or unbranched
2. Folded - making it compact for storage
3. Straight -making the molecules suitable to construct cellular structures- or coiled

Question 3

Give two reasons why starch and glycogen are storage polysaccharides

Answer 3

1. Compact -large quantities can be stored
2. Insoluble- no osmotic effect

Question 4

How and where is starched stored?

Answer 4

as granules in the plastids (e.g. chloroplasts)

Question 5

Why does it takes longer time to digest starch than glucose?

Answer 5

due to many monomers

Question 6

Describe the structure of amylose

Answer 6

1. It makes up (10% - 30% of starch)
2. Unbranched helix-shaped chain with 1,4 glycosidic bonds between a glycose molecules
3. The helix shape enables it to be more compact and thus its more resistant to digestion

Question 7

Describe the structures of Amylopectin

Answer 7

1. It makes up (70% -90% of starch)
2. 1,4 and 1,6 bonds between form between a-glucose creating a branched molecule
3. The branches result in many terminal glucose molecules that be easily hydrolyzed for use during cellular respiration or added to for storage

Question 8

Describe the structure of glycogen

Answer 8

1. storage polysaccharides of animals and fungi
2. highly branched and not coiled

Question 9

How is glycogen more compact than amylopectin?

Answer 9

It’s more branched (meaning more free ends where glucose can be removed or added allowing condensation and hydrolysis reaction to occur)