BM: Factors Affecting Enzyme Action

Question 1

What factors affect enzyme activity?

Answer 1

• Temperature
• pH
• Enzyme concentration
• Substrate concentration

Question 2

Draw a graph showing how temperature affects the rate of reaction:

Answer 2

Question 3

Draw a graph showing how pH affects enzyme action:

Answer 3

Question 4

Draw a diagram showing how enzyme concentration affects the rate of reaction:

Answer 4

Question 5

Describe the effect substrate concentration has on the rate of reaction:

Answer 5

• Higher concentration = faster reaction
• Saturation point is reaches - active sites are ‘full’
• If no other variables are changed, rate will fall as substrate conc. decreases with time.

Question 6

What are the two types of inhibition?

Answer 6

Competitive and non-competitive

Question 7

Describe competitive inhibition:

Answer 7

• Inhibitor molecules have similar shape to substrate molecules.
• Compete with substrate molecules to bind to active site.
• No reaction occurs, but they block active site.

Question 8

What happens if there is a high concentration of inhibitor molecules relative to substrate molecules?

Answer 8

Inhibitor wil ltake up nearly all of active sites.

Question 9

Describe non-competitive inhibition:

Answer 9

• Inhibitor molecules bind to allosteric site.
• Active site changes shape so substrate can no longer bind to it.

Question 10

What happens if substrate concentration is increased during competitive inhibition?

Answer 10

Rate will increase as substrates have an increased chance of reaching active site before inhibitor.

Question 11

What happens if substrate concentration is increased during non- competitive inhibition?

Answer 11

Reaction rate will stay the same - enxyme activity will still be inhibited.