Carbohydrate

Question 1

What are the three monosaccharides?

Answer 1

Glucose, fructose and galactose

Question 2

What is the formula for glucose?

Answer 2

C6H12O6

Question 3

What’s the difference between alpha and beta glucose?

Answer 3

A slight change in the arrangement in atoms in beta glucose. The hydrogen and hydroxide groups and carbon I are reversed from H at the top to bottom.

Question 4

What reaction occurs when a disaccharide is formed?

Answer 4

Condensation reaction. The molecule loses water during this reaction.

Question 5

How can a disaccharide be broken?

Answer 5

In a hydrolysis reaction, water is required for this.

Question 6

What type of bond is created in a disaccharide?

Answer 6

A glycosidic bond. The bond is between carbons 1 and 4.

Question 7

What is the general formula of disaccharides?

Answer 7

C12H22O11

Question 8

What are the two important disaccharides?

Answer 8

Maltose- two alpha glucose molecules, the product of starch digestion.
Sucrose- glucose and fructose, is the form in which carbohydrates are transported in plants.

Question 9

What is the general formula for polysaccharides?

Answer 9

(C6H10O5)n

Question 10

What are the main polysaccharides?

Answer 10

Starch, glycogen and cellulose.

Question 11

What are the two types of starch?

Answer 11

Amylose, it is approximately 20%.

Amylopectin, it is approximately 80%.

Question 12

What the alpha glucose molecules linked by in amylose?

Answer 12

1,4 glycosidic bonds. This forms long unbranched chains.

Question 13

What is the shape of amylose?

Answer 13

A coiled configuration due to each alpha glucose molecule lying at an angle to the next molecule.

Question 14

What is the difference between amylose and amylopectin?

Answer 14

Amylopectin also contains 1,6 glycosidic bonds, which formed branched molecules. There is approximately one branch in every 24-30 molecules in starch and one in every 8-10 glucose units in glycogen.

Question 15

Where is starch stored in?

Answer 15

Stored as solid grains in plant chloroplasts.

Question 16

Why is starch such a good storage molecule?

Answer 16

Amylose and amylopectin are both very compact, therefore contain a rich store of glucose in a small space.
It is insoluble, it will not affect the water relations with the cell.
It is a large molecule and can be retained in the cell and will not easily pass through the cell membrane.
The branching nature creates many terminal ends that are easily hydrolysed. This helps the rapid enzymatic breakdown of starch.
They are osmotically inert (only soluble substances affect the water potential of a cell).

Question 17

What is the difference between glycogen and starch?

Answer 17

In glycogen the chains are more branches and shorter than the amylopectin chains. It has more terminal ends, enabling faster hydrolysis.

Question 18

Where is glycogen stored in?

Answer 18

Liver and muscle cells.

Question 19

What type of polysaccharide is cellulose?

Answer 19

Structural.

Question 20

What do all monosaccharides have in common?

Answer 20

Molecular formula, but a different structural formula?

Question 21

What bond is formed in a condensation reaction for the formation of maltose?

Answer 21

Alpha 1-4 glycosidic bond. The two alpha glucose molecules are not in the same plane and the two molecules lie at different angles.

Question 22

What is cellulose composed of?

Answer 22

Beta glucose.

Question 23

Why does cellulose form straight chains?

Answer 23

Due to the way in which the beta glucose molecules are orientated. Every other beta glucose molecule is inverted due to the structure of beta glucose to ensure that glycosidic bonds are made.

Question 24

What are cellulose chains connected by?

Answer 24

Adjacent cellulose molecules are linked by hydrogen bonds and grouped to form micro fibrils.