Carbohydrates

Question 1

Elements in carbohydrate:

Answer 1

Contains carbon, oxygen and hydrogen

Question 2

Examples of monosaccharides:

Answer 2

Glucose, galactose, fructose

Question 3

Examples of disaccharides:

Answer 3

Sucrose, maltose, lactose

Question 4

Examples of polysaccharides:

Answer 4

Starch, glycogen, cellulose

Question 5

What is a condensation reaction?

Answer 5

When one monomer joins to another and a water molecule is removed

Question 6

What is a hydrolysis reaction?

Answer 6

When water molecules are added in the process of breaking bonds between molecules

Question 7

What is a glycosidic bond?

Answer 7

A chemical bond formed as the result of condensation between two monosaccharides

Question 8

Structure of starch;

Answer 8

Alpha glucose, branched, found in plants only

Question 9

Structure of glycogen:

Answer 9

Alpha glucose, branched, found in animals and fungi

Question 10

Structure of cellulose:

Answer 10

Beta glucose, unbranched, found in plants only

Question 11

What are microfibrils?

Answer 11

Cellulose fibres link together by hydrogen bonds which increases strength

Question 12

Two structural isomers of glucose:

Answer 12

Alpha and beta glucose

Question 13

Test for reducing sugars:

Answer 13

Add Benedict’s solution, heat in water bath, if present orange- red precipitate forms.

Question 14

Test for non-reducing sugars:

Answer 14

Heat with Benedict’s solution, heat with dilute HCl, neutralise using sodium hydrogencarbonate, test with Benedict’s

Question 15

Test for starch:

Answer 15

Add iodine, if starch present sample turns blue/black