Chapter 3- Carbohydrates

Question 1

What type of molecule is a carbohydrate?

Answer 1

A polymer

Question 2

What is the monomer that makes up carbohydrates?

Answer 2

Monosaccharides

Question 3

What type of monosaccharide is glucose

Answer 3

Hexose, has 6 carbons

Question 4

What are the two forms of glucose?

Answer 4

Alpha and beta

Question 5

What is the difference between alpha and beta glucose?

Answer 5

In alpha, the OH on carbon 1 is on the bottom
In beta, the OH on carbon 1 is on the top

Question 6

Why is glucose soluble?

Answer 6

It is a polar molecule

Question 7

What type of molecule is ribose?

Answer 7

A pentose monosaccharide, has 5 carbons

Question 8

What 3 elements make up carbohydrates?

Answer 8

1) oxygen
2) carbon
3) hydrogen

Question 9

What do 2 monosaccharides joined together form?

Answer 9

A disaccharide + water

Question 10

What happens during the synthesis of a disaccharide ?

Answer 10

A hydrogen atom on one monosaccharide bonds to the OH group on another, real easing a molecule of water.

Question 11

What type of reaction is the formation of disaccharides?

Answer 11

A condensation reaction

Question 12

What type of reaction is the break down of disaccharides?

Answer 12

A hydrolysis reaction

Question 13

What type of bond joins monosaccharides together?

Answer 13

A glycosidic bond. In maltose, it is alpha 1,4 glycosidic

Question 14

What does two alpha glucose molecules joined together form?

Answer 14

Maltose

Question 15

What does an alpha glucose and fructose joined together form?

Answer 15

Sucrose

Question 16

What forms when you join an alpha/ beta glucose and galactose?

Answer 16

Lactose

Question 17

What is a polysaccharide

Answer 17

When more than 2 monosaccharides join together

Question 18

What is starch?

Answer 18

Plants store glucose as starch. It is a mixture of amylose and amylopectin. Starch is insoluble in water, so it doesn’t cause water to enter cells by osmosis so it is good for storage.

Question 19

What is amylose?

Answer 19

A long unbranded chain of a- glucose. The angles of the glycosidic bonds give it a coiled structure. This makes it compact, so it’s good for storage because you can fit more in a small space. It only contains alpha 1,4 glycosidic bonds

Question 20

What is amylopectin?

Answer 20

A long, branched chain of a-glucose. It’s side branches allow enzymes that break down the molecule to get at the glycosidic bonds easily. This means glucose can be released easily. The chains are are alpha 1,4 glycosidic bonds and the branches are alpha 1,6 glycosidic bonds.

Question 21

What is glycogen?

Answer 21

The main energy storage material in animals. Animals store excess glucose as glycogen in cells.

2) it’s structure is similar to amylopectin however it has many more branches ( alpha 1,6 glycosidic bonds) coming off it. This means stored glucose can be released very quickly which is important for animals.

3) it is also a very compact molecule so good for storage.

Question 22

What is cellulose

Answer 22

1) it is a major component of cell walls in plants

2) it is made of long, unbranched chains of beta-glucose. When beta-glucose molecules bonds, they form straight chains and each alternate glucose monomer is flipped due to the position on the OH group. It contain beta 1,4 glycosidic bonds.

3) the cellulose chains are linked together by hydrogen bonds to form strong fibres called microfibrils. The strong fibres mean cellulose provides structural support for cells.