enzymes

Question 1

describe the lock and key model

Answer 1

> substrate binds to the active site for the enzyme to facilitate the reaction
a substrate will only fit the active site of one specific enzyme

Question 2

describe the induced fit model

Answer 2

> the enzyme changes its shape slightly
its flexible and moulds itself around the substrate - a conformational change
as it changes shape the enzyme puts a strain on the substrate
the strain distorts a particular bond and so lower activation energy is needed to break the bond

Question 3

what are competitive inhibitors?

Answer 3

> they are a type of enzyme inhibitor which bind directly to the active site to prevent the enzyme from working

Question 4

what are non - competitive inhibitors?

Answer 4

> they are a type of enzyme inhibitor which bind to an allosteric site, changing the shape of the active site so the substrate can no longer bond

Question 5

what factors affect enzyme activity?

Answer 5

• enzyme concentration
• substrate concentration
• concentration of inhibitor
• temperature
• pH

Question 6

how does temperature affect enzyme activity?

Answer 6

• if too low then there is not enough kinetic energy so the rate decreases
• if increased then there is more kinetic energy so the rate increases
• if too high then the enzymes denature so fewer enzyme substrate complexes form and the rate decreases

Question 7

how does pH affect enzyme activity?

Answer 7

• if too high/too low then enzymes denature so fewer enzyme substrate complexes form and rate decreases

Question 8

how was the concentration of inhibitor affect enzyme activity?

Answer 8

• increasing it means there are fewer enzyme substrate complexes so the rate decreases

Question 9

how does substrate concentration affect enzyme activity?

Answer 9

• increasing it means more enzyme substrate complexes form so the rate increases
• there are no empty active sites

Question 10

how does enzyme concentration affect enzyme activity?

Answer 10

• increasing it means more enzyme substrate complexes form so the rate increases