Polysaccharides

Question 1

What is a polysaccharide?

Answer 1

A polymer chain of either α-glucose or β-glucose monomers

Question 2

Name the two polysaccharides that gave α-glucose as their monomers

Answer 2

Starch
Glycogen

Question 3

What forms of starch are there?

Answer 3

Amylose
Amylopectin

Question 4

What is the difference between amylose and amylopectin?

Answer 4

Amylose forms a compact helical polysaccharide chain whilst amylopectin is branched creating a huge growth surface area and allowing it to be hydrolysed quicker

Question 5

Why is there more glycogen found in muscle and liver tissue?

Answer 5

Because they are the most metabolically active, needing more glucose to be hydrolysed to carry out its functions

Question 6

What are the differences between glycogen and amylopectin?

Answer 6

• Glycogen is found in animals, amylopectin is found in plants
• Glycogen is more branched and coiled

Question 7

What are the uses for polysaccharides?

Answer 7

• Cellulose is used from structure in plant walls
• Starch is used for energy storage in plants
• Glycogen is used for energy storage in animals

Question 8

Why is cellulose good for structural use?

Answer 8

It has many long straight unbranched chains which run parallel and are connected via hydrogen bonds

Question 9

What are cell walls made from?

Answer 9

Cellulose chains are tightly packed together forming micelles, and many micelles form microfibrils which in turn then is found inside fibrils

Question 10

How is β-glucose joined together in a polymer chain?

Answer 10

The molecule on the left flips over and the glycosidic bond is formed on the top, then the below, then the top etc

Question 11

How would you test a specimen for starch?

Answer 11

Add iodine solution to the sample and a blue black color change shows a a positive result