1.3

Question 1

What is the bond between monosaccharides called and what reaction takes place for it to occur

Answer 1

A condensation reaction takes place and the bond that is formed is called a glycosidic bond

Question 2

What is it called when water is added to break a bond. And what bond is being broken in this case

Answer 2

Hydrolysis-glycosidic bond

Question 3

What is the name of the test to detect non-reducing sugars

Answer 3

Benedict’s test

Question 4

Why does a non reducing sugar need to go through hydrolysis

Answer 4

As non reducing sugar have no colour change when heated with Benedict’s reagent it needs to go through hydrolysis so the colour change is visible

Question 5

What are the steps for Benedict’s test non reducing sugar

Answer 5

Add 2cm³ of food sample in test tube with 2cm³ of hydrochloric acid and boil for 5 min
Acid will hydrolyse disaccharides present into monosaccharides
Slowly add some sodium hydrocarbonate solution to test tube to neutralise acid
Test with pH paper if solution is alkaline
Repeat test using Benedict’s reagent if non reducing sugar was present solution will turn orange brown

Question 6

Why are polysaccharides suitable for storage

Answer 6

Polysaccharides are very large molecules meaning they are insoluble and therefore good for storage

Question 7

What is cellulose

Answer 7

Cellulose is a polysaccharide but is uses to give structural support instead of storage

Question 8

What is starch

Answer 8

Starch is a polysaccharide found in plants in the form of small granules or grains,

Question 9

How is starch formed

Answer 9

Starch is formed through the joining of 200-100,000 alpha glucose molecules through glycosidic bonds. Series of condensation reaction

Question 10

Test for starch

Answer 10

Place 2cm³ of sample being tested into a test tube
Add 2 drops of iodine solution and shake up or stir
Presence of starch indicated through blue or black colour change from orange