module 2 - carbohydrates

Question 1

what is a single sugar unit called?

Answer 1

a monosaccahride

Question 2

what is a carbohydrate compsed of?

Answer 2

carbon, oxygen,hydrogen

Question 3

what are 2 monosaccahrides joined together called?

Answer 3

a disaccahride polymer

Question 4

what are multiple monosaccahrides joined together called?

Answer 4

a polysaccahride

Question 5

what type of monosaccahride is glucose?

Answer 5

hexose monosaccahride as it contains 6 carbons

Question 6

what are the 2 types of glucose and what are their structures?

Answer 6

alpha glucose:
CH3OH
|
c——-o H
/ \ /
c c
\ / \
c——c OH

beta glucose:
CH3OH
|
c——-o OH
/ \ /
c c
\ / \
c——c H

Question 7

how do alpha and beta glucose differ from each other?

Answer 7

The hydroxyl group (OH) on carbon 1 is in opposite positions

This affects the structure and properties of the polysaccarides when it bonds

Question 8

how does a disaccharide form?

Answer 8

via the condensation of two monosaccharide
the hydroxyl group on one reacts with the hydrogen on the other to produce H2O
a glycosidic bond forms

Question 9

what bond forms during the condensation of 2 monosaccharides?

Answer 9

a glycosidic bond

Question 10

how is lactose made?

Answer 10

glucose + galactose

Question 11

how is maltose made?

Answer 11

glucose + glucose

Question 12

how is sucrose made?

Answer 12

glucose + fructose

Question 13

what is a pentose sugar?

Answer 13

sugar containing only 5 carbons e.g fructose

Question 14

what are the properties of starch?

Answer 14

> Compact
Chemical energy store
Easily digestible
Made of amylose (mainly, 1-4 glycosidic bonds) and amylopectin (1-4 and some 1-6 glycosidic bonds)
Insoluble does not create a water potential gradient (doesn’t cause water to enter cells by osmosis which would make them swell up)

Question 15

what are the properties of amylose?

Answer 15

> joined by 1-4 glycosidic bonding
compact - easily stored and released (twists into a helix)
metabolically inactive
held together by hydrogen bonds

Question 16

what are the properties of amylopectin?

Answer 16

> joined by 1-6 and 1-4 glucosidic bonds making it even more compact due to more bends
indelible - do not effect water potential
Branches gives ‘free ends’ so glucose can be added or released quickly

Question 17

what are the properties of glycogen?

Answer 17

> short, branched chains of alpha glucose
joined by 1-4 and 1-6 glycosidic bonds = compact and ideal for storage
Branches gives ‘free ends’ so glucose can be added or released quickly

Question 18

What is the function of glycogen?

Answer 18

Main energy store in animals

Stores soluble glucose that affects water potential as insoluble polysaccharide until needed

Question 19

what are the properties of glycogen?

Answer 19

> unbranched chain of beta glucose
forms beta pleated sheets as every other glucose molecule is orientated 180˚
1-4 glucosidic bonding
chains are linked by hydrogen bonds between functional groups forming strong fibres called microfibrils (compact)
microfibrils join to make macrofibrils, which combine to make fibres

Question 20

what is the function of cellulose?

Answer 20

> important part of our diet as it is very hard to breakdown so if the fibre necessary for a healthy digestive system
Cellulose provides structural support for cells

Question 21

how is a disaccharide broken?

Answer 21

hydrolysis