Carbohydrates

Question 1

How are polysaccharides formed?

Answer 1

Created by a condensation reaction between many glucose monomers.

Question 2

What are the three main polysaccharides?

Answer 2

Starch cellulose glycogen

Question 3

• How is starch formed?
• Where is starch found?
• What is the function of starch?

Answer 3

Formed from two polymers of alpha glucose: amylose and amylopectin

Fond in starch grains inside plant cells

Function - insoluble store of glucose

Question 4

What is amylose?

Answer 4

Polymer of alpha glucose

Created in condensation reaction

Forms a 1-4 glycosidic bond (straight chain that coils up to form an unbranched helix)

Question 5

What is amylopectin?

Answer 5

Polymer of alpha glucose

Formed by condensation reactions

1-4 and 1-6 glycosidic bond creates a branch (branched molecule)

Question 6

• How is glycogen formed?
• Where is glycogen found?
• What is the function of glycogen?

Answer 6

Formed from condensation reactions between alpha glucose

Found in muscle and liver cells in animals

Function- insoluble store of glucose

Question 7

What is the structure of glycogen?

Answer 7

Contains 1-4 and 1-6 glycosidic bonds

Glycogen has even more 1-6 glycosidic bonds than amylopectin

It is highly branched, can be compacted to fit large amounts of glucose

Question 8

• How is cellulose formed?
• Where is cellulose found?
• What is the function of cellulose?

Answer 8

Formed from beta glucose In condensation reactions

Found in cell wall of plant cells

Function- provides structural strength to cell wall

Question 9

What is the structure of cellulose?

Answer 9

Only 1-4 glycosidic bonds

Creates long, straight chains of beta glucose

The chains line up parallel to each other and are held in place by hydrogen bonds ( a fibril )

Hydrogen bonds individually are weak but because of the large number of them, they provide strength

Question 10

How does the structure of starch lead to its function?

Answer 10

Helix can compact to fit a lot of glucose in a small place

Insoluble so it won’t affect water potential

Question 11

How does the structure of cellulose lead to its function?

Answer 11

Long straight chains are joined together by hydrogen bonds to form a fibril which provides strength to the cell wall

Insoluble so it won’t affect water potential

Question 12

How does the structural of glycogen lead to its function?

Answer 12

Branched structure increases surface area for rapid hydrolysis back to glucose

Insoluble so it won’t affect water potential

Question 13

What are disaccharides?

Answer 13

Simple sugars

Molecules made up of two monosaccharides

Joined together by a 1-4 glycosidic bond

Formed in a condensation reaction

Question 14

What are the examples of disaccharides?

Answer 14

glucose + glucose -> maltose + water
glucose + galactose -> lactose + water
glucose + fructose -> sucrose + water

Question 15

What is a condensation reaction?

Answer 15

Joining two molecules together to form a chemical bond by removing a molecule of water

Question 16

What is a hydrolysis reaction?

Answer 16

Breaking a chemical bond between two molecules by using a water molecule.

Question 17

What are monosaccharides

Answer 17

A monomer of carbohydrates
Simple sugars

Question 18

What are the examples of monosaccharides?

Answer 18

Glucose
Galactose
Fructose

Question 19

Draw alpha glucose

Question 20

Draw beta glucose

Question 21

How can glycogen act as a source of energy?

Answer 21

It can be hydrolysed back to glucose which can be used in respiration.

Question 22

Give three ways the structure of chitin similar to the structure of cellulose?

Answer 22

• Both contain 1,4 glycosidic bonds
• Both made up of beta glucose
• Both made up of straight chains