Carbohydrates

Question 1

3 things monosaccharides are

Answer 1

Single sugar unit
Sweet tasting
Soluble

Question 2

What is the ratio of carbon:hydrogen:oxygen in monosaccharides

Answer 2

1:2:1

CnH2nOn

Question 3

Sugar with 3 carbons

Answer 3

Triose

Question 4

Sugar with 5 carbons

Answer 4

Pentose

Question 5

Sugar with 6 carbons

Answer 5

Hexose

Question 6

What are isomers?

Answer 6

Same formulae but different layouts

Eg alpha and beta glucose

Question 7

Maltose is made of

Answer 7

2 alpha glucose

Question 8

What is the bond formed in maltose

Answer 8

Alpha 1-4 glycosidic bond

Question 9

Is maltose a reducing sugar and why?

Answer 9

Yes, has a free carbon 1

Question 10

How can you test for a reducing sugar?

Answer 10

Add Benedict’s solution, if it goes from blue to brick red a reducing sugar is present.

Question 11

What is sucrose made from?

Answer 11

Alpha glucose and fructose

Question 12

What is the bond in sucrose?

Answer 12

Alpha 1-2 glycosidic bond

Question 13

Is sucrose a reducing sugar?

Answer 13

No, there is no free C1 on the glucose and no free C2 on the fructose.
If you hydrolysed it, it would work.

Question 14

What is lactose made of?

Answer 14

Alpha glucose and galactose

Question 15

What are maltose, sucrose and lactose?

Answer 15

Disaccharides

Question 16

3 polysaccharides are

Answer 16

Starch
Glycogen
Cellulose

Question 17

Structure of starch

Answer 17

Mixture of 2 polysaccharides.
Amylose- unbranched chain. Coiled. Alpha 1-4 g bonds
Amylopectin - branched, curves, alpha 1-4 and 1-6 g bonds. Compact.

Question 18

Function of starch

Answer 18

Cells get energy from glucose, excess stored as starch. More glucose needed, starch hydrolysed.
Amylopectin branches easiest to break

Question 19

Structure of glycogen

Answer 19

Branched
Alpha 1-4 and 1-6 glycosidic bonds
Compact (curves)

Question 20

Function of glycogen

Answer 20

Compact so good for storage lots of energy in a small space.
Branched (a 1-6 bonds) so easily hydrolysed into glucose
Insoluble so doesn’t affect water potential

Question 21

Structure of cellulose

Answer 21

Straight, parallel chains of beta glucose, every second beta glucose is inverted.
Hydrogen bonds hold them together to form strong microfibrils which make cellulose insoluble

Question 22

Function of cellulose

Answer 22

Major component of cell walls in plants
Strong because of hydrogen bonds linking chains together
Provide structural support for cells

Question 23

Why are glycogen and starch good energy stores?

Answer 23

Very compact, don’t take up space, lots of energy can be stored
Branching allows polysaccharide to be hydrolysed to glucose rapidly when needed for energy.
Insoluble - doesn’t effect water potential of cell.