Polysaccharides

Question 1

What is a polysaccharide?

Answer 1

Polymer of monosaccharides formed by many condensation reactions

Question 2

What are the properties of polysaccharides?

Answer 2

Insoluble so don’t affect osmosis
Compact so can be stored in a small place in the cell
Easily hydrolysed to release the glucose for respiration

Question 3

What is glucose?

Answer 3

Main source of energy in cells
Must be stored in an appropriate form
Soluble in water = would affect osmosis within the cell
Overcome by converting glucose into storage polysaccharides

Question 4

What are the 4 examples of polysaccharides?

Answer 4

Starch
Glycogen
Cellulose
Chitin

Question 5

What are 2 examples of energy storage polysaccharides?

Answer 5

Starch - found in plants
Glycogen - found in liver and muscles

Question 6

What are 2 examples of structural function polysaccharides?

Answer 6

Cellulose
Chitin

Question 7

What is the function of starch?

Answer 7

Energy storage in plants

Question 8

What are the 2 different molecules that make up starch?

Answer 8

Amylose
Amylopectin

Question 9

What is starch?

Answer 9

Glucose energy storage polysaccharide in plant cells

Question 10

Describe the structure of starch

Answer 10

Made up of thousands of alpha glucose monomers

Question 11

Describe the structure of amylose

Answer 11

Straight chained
Helical polymer
Alpha 1-4 glycosidic bonds
Unbranched

Question 12

Describe the structure of amylopectin

Answer 12

Branched polymer
Alpha 1-4 and 1-6 glycosidic bonds

Question 13

What is the function of glycogen?

Answer 13

Energy storage in animals

Question 14

What is glycogen?

Answer 14

Animals energy storage polysaccharide found inside liver and muscle cells

Question 15

Describe the structure of glycogen

Answer 15

Alpha 1-4 and 1-6 glycosidic bonds
Highly branched

Question 16

How does the structure of glycogen relate to its function?

Answer 16

Highly branches
Enables the rapid hydrolysis of glucose molecules
From the ends of branches to be used in respiration

Question 17

What is the function of cellulose?

Answer 17

Important in plants as a structural carbohydrate
Important component of the plant cell all
Gives plant cell rigidity as the cellulose cell is inelastic
Has a high tensile strength to prevent plant cell from bursting

Question 18

Describe the structure of cellulose

Answer 18

Consists of many beta glucose molecules joined by beta 1-4 glycosidic bonds
Alternate glucose molecules rotate 180 degrees
Allows hydrogen bonds between parallel chains, forming microfibrils
Many microfibrils form a strong cellulose bundle

Question 19

What is the function of chitin?

Answer 19

Found in the exoskeleton of insects, crustaceans, arachnids and cell wall of fungi

Question 20

Describe the structure of chitin

Answer 20

Composed of many beta glucose molecules joined together with 1-4 glycosidic bonds
Contains acetyl amine group bonded to carbon 2 of the beta glucose monosaccharide
Beta glucose molecules are inverted to form the 1-4 glycosidic bonds
Chitin chains are straight which are parallel to each other
Has hydrogen bonds forming cross-links between the chains
Cross-linked chitin chains bundle together to form stronger microfibrils

Question 21

What are the properties of chitin?

Answer 21

Strong - used to give strength to exoskeleton
Waterproof - helps insects prevent water loss from their body
Lightweight - allows to insects to carry exoskeleton