A1, A2 Biological Molecules HARD PPQs

Explain why amylase produced in the human digestive system does not digest GOS

1. Active site only complementary to starch / not complementary to GOS

2. due to tertiary structure

Prebiotics are foods used to promote good health in humans.
Prebiotics stimulate the growth of 'healthy' bacterial populations in the human digestive system.
The bacteria in these 'healthy' populations produce enzymes that hydrolyse GOS.

Suggest how GOS can work as a prebiotic.

1. provides galactose

2. bacteria use galactose for respiration

3. bacteria use galactose for binary fission 

describe the structure of proteins (5)

1. polymer of amino acids

2. joined by peptide bonds

3. formed in condensation reaction

4. primary structure- sequence of amino acids

5. secondary structure- folding of polypeptide chain due to hydrogen bonding

6. tertiary structure- 3D folding due to hydrogen bonding and ionic bonds

7. quaternary structure- two or more polypeptide chains

2 proteins have the same number and type of amino acids but different tertiary structures, explain why

1. different sequence of amino acids

2. forms ionic bonds in different places