Biological Molecules- Factors Affecting Enzyme Action

Question 1

How does increasing temperature affect enzyme action?

Answer 1

Rise in temperature makes molecules vibrate more but above a certain point vibration breaks bonds and active site changes shape so enzyme is denatured

Question 2

How does changing pH affect enzyme activity?

Answer 2

Above and below optimum temperature, H+ and OH- bonds can mess with bonds in tertiary structure so active site changes shape and denatures enzymes

Question 3

How does enzyme concentration affect rate of reaction?

Answer 3

More enzyme molecules mean that collision between enzymes and substrate is more likely so rate of reaction will increase until there are no more substrates so adding more enzymes has no further effect so substrate concentration is limiting factor

Question 4

How does substrate concentration affect rate of reaction?

Answer 4

Collision is more likely initially so rate of reaction increases until active sites are all full so adding more substrates make no difference to rate of reaction

Question 5

What is a competitive inhibitor?

Answer 5

• Similar shape to substrate molecules
• Compete with substrate molecules to bind to active site
• Block substrate from binding
• High concentration of inhibitor means nearly all active sites are taken up
• Higher concentration of substrate means chances of getting to an active site before inhibitor increases so rate of reaction will increase

Question 6

What is a non-competitive inhibitor?

Answer 6

• Bind to enzymes away from active site
• Active site changes shape so substrate molecules can no longer bind
• Increasing concentration of substrate won’t make any difference to rate of reaction