Carbohydrates

Question 1

What is a disaccharide?

Answer 1

A disaccaride is 2 monosaccharides bound together by a glycosidic bond. Mosts disaccharides contain at least 1 glucose monosaccharide.

Question 2

Glucose + Glucose =

Answer 2

Maltose

Question 3

Glucose + Fructose =

Answer 3

Sucrose

Question 4

Glucose + Galactose =

Answer 4

Lactose

Question 5

Where do glycosidic bonds form?

Answer 5

Glycosidic bonds form between 2 monosaccarides using a condensation reaction. The same mechanism is used to add a monosaccharide onto a polysaccaride.
In maltose, this bond forms between carbon 1 on the first a-glucose and carbon 4 on the second, so it is an a-1-4-glycosidic bond.

Question 6

What reaction breaks down glycosidic bonds?

Answer 6

Hydrolysis

Question 7

What is starch?

Answer 7

An energy storage molecule found in plants. It is the source of carbohydrate in our food.

Question 8

What is starch made of?

Answer 8

Amylopectin and amylose

Question 9

What is the structure of amylopectin?

Answer 9

Branched with a few long branches, made of a-glucose.

Question 10

What is the structure of amylose?

Answer 10

Coiled structure made of a-glucose.

Question 11

What is glycogen?

Answer 11

An energy storage found in animals and people. Any excess glucose in our diet is stored as glycogen in the liver and muscles. When our blood glucose levels are low, glycogen is converted back into glucose. Glycogen is made of a-glucose and has a similar structure to amylopectin (branched).

Question 12

What is the structure of cellulose?

Answer 12

Cellulose is found in cell walls of plant cells and gives structure and support. It is made of B-glucose monomers that form long straight chains. Hydrogen bonds form between adjacent strands to provide strength to the cells.

Question 13

What are the properties and functions of starch?

Answer 13

• Energy store in plants
• Insoluble
• Does not affect the water potential of the plant.
• Branches can be easily broken so that glucose can be used in respiration.

Question 14

What are the properties and functions of glycogen?

Answer 14

• Energy storage in animals
• Insoluble
• Does not affect the water potential of the animal cell.
• Branches can easily be broken so that glucose can be used in respiration.

Question 15

What are the properties and functions of cellulose?

Answer 15

• Structural carbohydrate in plant cell walls.

- Hydrogen bonds between cellulose chains gives strength to cell walls.