Carbohydrates

Question 1

What reaction occurs when two monosaccharides are joined?

Answer 1

A condensation reaction.

Question 2

What reaction occurs when a polysaccharide is broken down into smaller saccharides?

Answer 2

Hydrolysis.

Question 3

What functional group does the condensation reaction occur between in carbohydrates?

Answer 3

Hydroxyls. (OH)

Question 4

Draw alpha glucose.

Answer 4

See alpha glucose diagram.

Question 5

Draw beta glucose.

Answer 5

See beta glucose diagram.

Question 6

What are the 4 monosaccharides?

Answer 6

• Alpha glucose
• Beta glucose
• Fructose
• Galactose

Question 7

What are the 3 disaccharides?

Answer 7

• Maltose
• Sucrose
• Lactose

Question 8

What monosaccharides make up maltose?

Answer 8

2 alpha glucoses.

Question 9

What monosaccharides make up sucrose?

Answer 9

An alpha glucose and a fructose.

Question 10

What monosaccharides make up lactose?

Answer 10

An alpha glucose and a galactose.

Question 11

How many carbons are hexose sugars made up of?

Answer 11

6

Question 12

What are isomers?

Answer 12

Molecules that have the same chemical formula, but have a different arrangement of the atoms in space.

Question 13

Give an example of an isomer and explain why they are isomers.

Answer 13

Alpha glucose and beta glucose.
The -OH and -H are swapped round on the 1st prime carbon on the plane of the molecule.

Question 14

Name the 3 polymers made from glucose?

Answer 14

• Starch
• Glycogen
• Cellulose

Question 15

What monomer makes up starch?

Answer 15

Alpha glucose.

Question 16

Where is starch found?

Answer 16

In starch grains, which are found within plant cells.

Question 17

What two polymers are found within starch?

Answer 17

Amylose and amylopectin.

Question 18

What is the difference between amylose and amylopectin and what is the structure of them (and therefore starch)?

Answer 18

• Amylose forms 1-4 glycosidic bonds and folds into a helical structure (coiled).
• Amylopectin forms 1-4 and 1-6 glycosidic bonds, which means it can be branched.

Question 19

How does starch’s structure relate to function?

Answer 19

• The helix is compact and so can fit a large amount of glucose in a small space due to coiling.
• The molecule is insoluble and so will not impact the water potential of the cell.
• The branched structure increases the rate at which enzymes can hydrolyse the starch into glucose.

Question 20

What monomer makes up glycogen?

Answer 20

Alpha glucose.

Question 21

Where is glycogen found?

Answer 21

In muscle and liver cells in animals.

Question 22

What is the structure of glycogen?

Answer 22

• Alpha glucose molecules held together by 1-4 and 1-6 glycosidic bonds. (it is more branched than amylopectin due to having more 1-6 bonds)

Question 23

How does glycogen’s structure relate to function?

Answer 23

• Highly branched structure due to 1-6 glycosidic bonds allows enzymes to rapidly hydrolyse the molecule into many glucose molecules.
• The molecule is insoluble and so will not affect the water potential of the cell.

Question 24

What monomer makes up cellulose?

Answer 24

Beta glucose.

Question 25

Where is cellulose found?

Answer 25

In the cell walls of plants.

Question 26

What is the structure of cellulose?

Answer 26

• Due to the structure of beta glucose, every other beta glucose must be inverted to form a chain of 1-4 glycosidic bonds.
• Many of these chains arrange themselves in parallel to one another.
• These chains are held together by many weak hydrogen bonds to form a fibril.

Question 27

How does cellulose’s structure relate to function?

Answer 27

• Every other beta glucose molecule is inverted allowing the formation of many weak hydrogen bonds and fibrils.
• Many hydrogen bonds provide collective strength.
• The molecule is insoluble and so does not affect the water potential of the cell.