carbohydrate: starch and glycogen

Question 1

what are the two types of linked polymers found in starch

Answer 1

• Two types of linked polymer: amylose and amylopectin

Question 2

what is the structure of amylose and amylopectin?

Answer 2

Amylose has alpha 1,4 glycosidic links and assumes a helical coil shape (30-20%)

Amylopectin has alpha 1,4 and 1,6 glycosidic links and assumes a brush shape (70-80%)

Question 3

what is starch

Answer 3

Starch is a polymer of alpha-glucose

• Starch is the main source of carbohydrate in the diet.
• It is the main storage polymer of plants.

Question 4

where is starch found in?

Answer 4

• Found in amyloplasts and chloroplasts of plant cells originating from roots, tubers, seeds and fruits

Question 5

describe the digestion of starch

Answer 5

• Digested by amylase and maltase in the saliva and gastrointestinal tract to maltodextrins, maltotriose, maltose and glucose

Question 6

what is the structure of glycogen?

Answer 6

• Glycogen is a polymer of alpha-glucose

* Contains both alpha 1,4 glycosidic links and alpha 1,6 alpha glycosidic links and is very similar to amylopectin

Question 7

describe the characteristics of glycogen and its function

Answer 7

• Branch points occur more frequently than in starch, every 8 to 12 residues
• Complex, highly branched structure
• Main storage polymer of animals, found in liver and muscle cells
• Readily hydrolysed for energy when required

Question 8

where are starch and glycogen found?

Answer 8

starch in chloroplast in plants

glycogen in glycogen granules in cytoplasm of amnimal cells