Carbohydrates

Question 1

Name the three types of carbohydrates

Answer 1

Monosaccharides
Disaccharides
Polysaccharides

Question 2

Draw an alpha glucose

Answer 2

5 carbons 
First carbon OH group below H above 
Second carbon OH below H above 
3rd carbon H below OH above 
4th C Oh below h above 
5th C h below CH20H above 
Oxygen

Question 3

Two ways in which glucose molecule is well suited to its function in living organisms

Answer 3

Glucose is soluble so can easily be transported in the blood
Glucose can be easily broken down to release energy in respiration to make atp
Glucose is small so can be easily transported across membranes

Question 4

Which two monomers are joined together to form:
Maltose?
Sucrose?
Lactose?

Answer 4

Maltose= Glucose, Glucose 1,4
Sucrose= Glucose, Fructose 1,2
Lactose = Galactose, Glucose 1,4

Question 5

What two compounds make up starch?

Describe there functions and structure

Answer 5

Amylose- 300 Glucose molecules held together by 1:4 glycosidic bonds and forms an unbranched helix
Compact energy store, insoluble therefore does not affect the osmotic potential of a cell the way glucose would
Amylopectin is made of short, branched chains was 1:6 glycosidic bond, branched so easily broken down

Question 6

Function and structure of Glycogen

Answer 6

Glucose molecules held together by a 1:4 glycosidic bonds at branching points
Compact energy store

Question 7

Function and structure of cellulose

Answer 7

Function and structure of cellulose
300 to 2500 beta glucose molecules held together by 1:4 glycosidic bonds
Position of OH groups causes every other molecule to become inverted
Forms long, linear branched chains
Chains have OH groups sticking out which form hydrogen bonds with other chains producing micro fibrils
Very strong, makes up cell wall

Question 8

Make a comparison between glycogen and cellulose

Answer 8

Cellulose is found in plants, glycogen in animals
Cellulose made of beta glucose
Only has 1-4 glycosidic bonds
Glycogen has 1-4 and 1-6 glycosidic bonds

Question 9

Describe Benedicts test for reducing sugars

Answer 9

Add benedicts reagent to the sample
Heat to 80oc for 5 minutes
If the solution changes from blue to red than a reducing sugar, such as glucose, fructose or maltose is present

Question 10

Test for non-reducing sugar

Answer 10

After a negative result with benedicts
Add hydrochloric acid to a fresh sample
Neutralise with sodium hydrogen carbonate
Then heat with benedicts
Blue to orange red then non reducing is present