Molecules Past Paper Questions

Question 1

Galactose- C6H12O6
Glucose- C6H12O6
Fructose- C6H12O6

Calculate the number of Carbon, Hydrogen and Oxygen atoms in a molecule

Answer 1

-2 glycosidic bonds- 2 Condensation Reactions- (H20 x2)

-C= 18
-H= 32
-O= 16

Question 2

What is a Monomer?

Answer 2

A repeating molecule from which larger molecules/ polymers are made

Question 3

Describe two differences between the structure of a Cellulose and Glycogen molecule

Answer 3

1. Cellulose is made of Beta Glucose molecules, whereas Glycogen is made of Alpha Glucose molecules
2. Glycogen is a branched molecule whereas Cellulose is an unbranched molecule
3. Glycogen has 1,4 and 1,6 glycosidic bonds whereas Cellulose only has 1,4 glycosidic bonds

Question 4

Describe and Explain two features that make starch a good storage molecule

Answer 4

1. Starch is Insoluble, therefore it won’t affect osmotic balance/ water potential
2. Starch coils up, therefore it is compact, meaning little volume is taken (rich glucose store)
3. Starch is a branched molecule, therefore the terminal ends can be easily hydrolysed giving a quick starch breakdown, meaning glucose is available at high respiratory times