Carbohydrates

Question 1

What type of hexose sugar is glucose?

Answer 1

It is a monosaccharide.

Question 2

What sugar is in a DNA nucleotide?

Answer 2

Deoxyribose

Question 2

What sugar is in a DNA nucleotide?

Answer 2

Deoxyribose

Question 3

What sugar is in RNA?

Answer 3

Ribose.

Question 4

What groups does a sugar have?

Answer 4

Hydroxyl, carbon and aldehyde.

Question 5

Why is glucose small?

Answer 5

Glucose forms a compact helix due to intramolecular interactions. (Hydrogen bonds)

Question 6

What are isomers?

Answer 6

A compound with the same molecular formula but a different arrangement. E.g a glucose and b glucose.

Question 7

What disaccharide is formed by a glucose and b glucose undergoing a condensation reaction?

Answer 7

Starch (amylose)

Question 8

Carbohydrate formulae:

Answer 8

Cx(H2O)x or (CH2O)n

Question 9

Glucose + glucose =

Answer 9

Maltose

Question 10

Glucose + galactose =

Answer 10

Lactose

Question 11

Glucose + fructose =

Answer 11

Sucrose

Question 12

What is the 1 non-reducing sugar?

Answer 12

Sucrose

Question 13

What do all reducing sugars contain?

Answer 13

Have a free ketone or adelhyde group

Question 14

Amylose properties,

Answer 14

• Made from alpha glucose
• coiled and unbranched
• 1-4 glycosidic bonds
• h bond within molecules
• Granular

Question 15

Cellulose properties

Answer 15

-Fibrous -‘Fibrous chains’
-Not coiled
1-4 glycosidic bonds
-Beta glucose
-H bonds between adjacent molecules.
-Monomers alternatively at 180° to eachother

Question 16

Is glycogen more compact than Amylopectin?

Answer 16

Yes

Question 17

What bonds are between every 25 glucose molecules in amylopectin?

Answer 17

Alpha 1-6 glycosidic bonds.

Question 18

Why does amylopectin hydrolyse rapidly?

Answer 18

Amylopectin is branched with many protruding ends.

Question 19

Starch is made of…

Answer 19

Amylose + amylopectin

Question 20

How can you identify what type of plant a starch polysaccharide comes from?

Answer 20

Microscopic analysis of the differing lengths of amylopectin and amylose.

Question 21

Chitin:

Answer 21

A structural polysaccharide found in all exoskeletons of arthropods and in the hyphal walls of many fungi.
(Glucose + amino acid) glucosamine units linked by beta 1-4 glycosidic bonds.

Question 22

What does the amino acid present in chitin affect?

Answer 22

Causes more hydrogen bonding, making it extremely resilient and a tough polysaccharide

Question 23

Glycogen is similar to…

Answer 23

Amylopectin

Question 24

Difference between Glycogen and amylopectin?

Answer 24

Glycogen is in animals and has more branches, which are shorter; and so glycogen has more free ends which can be hydrolysed and so glycogen hydrolyses faster. This because animals need a fast release of glucose which can be used for respiration to provide energy for motion. Glycogen is less dense than starch and-so is less compact Glycogen is more soluble than starch and-so is more easily transported. Glycogen contains alpha glucose 1:6 glycosidic bonds Glycogen and amylopectinforms granules.

Question 25

Cellulose form a ....

Answer 25

Fibrous chain (microfibrils) and are used as structural support for the plant. It is non-granular

Question 26

What form polysaccharides?

Answer 26

Many glucose units.

Question 28

+ve test for starch.

Answer 28

Iodine - turns blue.

Question 29

What carbohydrate molecule is used to store energy in plants?

Answer 29

Starch

Question 30

What carbohydrate molecule is used to store energy in animals.

Answer 30

Glycogen

Question 31

What bonds are in glycogen?

Answer 31

composed of alpha-1,4-glycosidic bonds with branched alpha-1,6 bonds present at about every tenth monomer

Question 32

What are two similarities between Chitin and glycogen?

Answer 32

Both are polysaccharides and both are made up of hexose sugar units.

Question 33

What are two differences between Chitin and glycogen?

Answer 33

Chitin contains nitrogen, whilst glycogen does not. | Glycogen is branched whilst Chitin is not.

Question 34

Test for reducing sugar:

Answer 34

Add Benedicts reagent - mix - heat - colour change for positive result - amount of cchange shows concentration of sugar.

Question 35

Test for non-reducing sugar:

Answer 35

Add dilute HCL - Boil - cool and neutralize with excess sodiumhydroxide - repeat test for reducing sugar.

Question 36

What are the 6 functions of carbohydrates?

Answer 36

``` Immediate respiratory substrates Energy stores Structural components Metabolites Cell-to-cell attachment Transport ```

Question 37

Why is cellulose a good structural polysaccharide?

Answer 37

Its hydrogen bonding prevents water from entering the molecule, making it resistant to enzyme hydrolysis