Starch

Question 1

What is starch?

Answer 1

Starch is a polysaccharide formed from condensation reaction between glucose linked by glycosidic bonds.

Question 2

What are the two components of starch?

Answer 2

amylose and amylopectin.

Question 3

Describe amylose.

Answer 3

*unbranched chains of glucose with glycosidic bonds
*helical structure.
*The OH groups point inward, forming hydrogen bonds to hold the helix in place.

Question 4

Describe amylopectin.

Answer 4

*branched chains with 1-6 glycosidic bonds between glucose molecules.

Question 5

What is the composition of starch in terms of amylose and amylopectin?

Answer 5

Starch is composed of 20% amylose and 80% amylopectin.

Question 6

Where is starch found?

Answer 6

Starch is found in chloroplasts or amyloplasts as starch grains.

Question 7

Why is starch a good storage molecule?

Answer 7

*insoluble- doesn’t affect osmosis
*large molecule- doesn’t diffuse out cell
*compact
*readily hydrolysed to form glucose (energy) glucose can be released rapidly