1.2 Carbohydrates

Question 1

What are monosaccharides?

Answer 1

Monosaccharides are the monomers from which larger carbohydrates are made.

Question 2

What are the examples of monosaccharides?

Answer 2

1. glucose
2. galactose
3. fructose

Question 3

How do monosaccharides taste?

Answer 3

Sweet

Question 4

Are monosaccharides soluble or insoluble?

Answer 4

Soluble

Question 5

What is monosaccharide’s general formula?

Answer 5

(CH2O)n

Question 6

What are glucose’s isomers?

Answer 6

α-glucose and β-glucose

Question 7

What is the difference between α-glucose and β-glucose?

Answer 7

α-glucose: H group above the plane, OH group below the plane
β-glucose: OH group above the plane, H group below the plane

Question 8

What are disaccharides?

Answer 8

Disaccharide is a sugar that is formed by combining two monosaccharides.

Question 9

How are disaccharides formed?

Answer 9

Condensation of two monosaccharides

Question 10

What will be formed when condensation reaction happens between two monosaccharides?

Answer 10

A glycosidic bond

Question 11

What are the examples of disaccharides?

Answer 11

1. maltose
2. sucrose
3. lactose

Question 12

How is maltose formed?

Answer 12

Condensation of two glucose molecules

Question 13

How is sucrose formed?

Answer 13

Condensation of an aglucose molecule and a fructose molecule

Question 14

How is lactose formed?

Answer 14

Condensation of a glucose molecule and a galactose molecule

Question 15

What are polysaccharides?

Answer 15

Polysaccharides are polymers that are formed by combining many monosaccharides.

Question 16

How are polysaccharides formed?

Answer 16

Condensation of many glucose
units/monosaccharides

Question 17

What will be formed when condensation reaction happens between many monosaccharides?

Answer 17

Glycosidic bonds

Question 18

What are the examples of polysaccharides?

Answer 18

1. glycogen
2. starch
3. cellulose

Question 19

How are glycogen and starch formed?

Answer 19

Condensation of α-glucose

Question 20

What are the function of glycogen and starch?

Answer 20

Energy source

Question 21

How are cellulose formed?

Answer 21

Condensation of β-glucose

Question 22

What is the function of cellulose?

Answer 22

Structural support to plant cells

Question 23

Are polysaccharides soluble or insoluble? Why?

Answer 23

Insoluble, because they are very large molecules.

Question 24

What are the features of starch? Explain each of them.

Answer 24

1. insoluble - so it doesn’t affect water potential > water isn’t drawn into cells by osmosis + so it doesn’t diffuse out of the cell
2. compact (緊湊) - so a lot of it can be stored in a small place
3. when hydrolysed it forms α-glucose - so it’s easily transported and readily used in respiration
4. the branched form has many ends - so each of it can be acted on by enzymes simultaneously, meaning that glucose monomers can be released very rapidly

Question 25

Is starch never been found in animal, plant or bacterial cells?

Answer 25

Animal cells

Question 26

Is glycogen found in animal, plant or bacterial cells?

Answer 26

Animal cells

Question 27

What is used to test for reducing sugars and non-reducing sugars?

Answer 27

Benedict’s solution

Question 28

What is used to test for starch?

Answer 28

Iodine/potassium iodide