Factors Affecting Enzyme Activity

Question 1

Define the term ‘denaturation’.

Answer 1

Loss of active site shape

Question 2

Explain how an increase of temperature increases enzyme activity.

Answer 2

• Increasing temperature increases particles’ kinetic energy
• Particles move faster and collide more often
• More successful collisions (between active site and substrate)

Question 3

Explain how high temperatures can denature enzymes.

Answer 3

• High temperature leads to more vibrations
• Too much vibration breaks the bonds that hold the protein together

Question 4

What is the temperature coefficient (Q10)?

Answer 4

A measure of how much the reaction rate increases with a 10°C increase

Question 5

How are the enzymes in organisms that live in cold environments adapted?

Answer 5

• enzymes are more flexible, hence less stable
• can move more in low KE environment to bind

Question 6

How are the enzymes in organisms that live in hot environments adapted?

Answer 6

• enzymes are more stable (have more bonds in tertiary structure)
• more resistant to denaturation by high heat

Question 7

How does a change in pH affect enzyme structure?

Answer 7

• A change in pH refers to a change in H+ concentration
• H+ ions interact with polar and charged R groups in tertiary structures
• This breaks the bonds/interactions between R groups, leading to loss of tertiary structure

Question 8

Explain why an increase in substrate concentration increases rate of reaction.

Answer 8

• Higher successful collision rate
• Between active site and the substrate
• Forming more enzyme-substrate complexes