factors affecting enzyme action (module 1)

Question 1

how does temperature affect enzyme activity?

Answer 1

• as temperature increases so does rate of reaction
• because more kinetic energy so more collisions between enzyme and substrate
• after the optimum temperature enzyme denatures so no longer complementary to substrate
• so ES complexes can’t form

Question 2

how does pH affect enzyme activity?

Answer 2

• if pH to high or low will affect the charges on the amino acids in the active site
• this can stage the tertiary structure of active site so no longer complementary to substrate
• so less ES complexes formed
• different enzymes have different optimum pH

Question 3

how does enzyme concentration affect activity?

Answer 3

• if there is insufficient enzymes, all active sites will become used up
• so even if enzymes concentration increases there will be no increase in rate of reaction
• due to all substrate being used up so it becomes a limiting factor

Question 4

how does substrate concentration affect activity?

Answer 4

• if there is insufficient substrate then there will slower reaction and fewer collisions to form ES complexes
• so even if increase substrate no increase in rate of reaction as not enough enzyme active site

Question 5

what are inhibitors?

Answer 5

substances that bind to enzymes and slow down the rate of reaction so less product made

Question 6

what are competitive inhibitors?

Answer 6

• similar structure to substrate
• competes for active site
• less ES complexes form so less product formed
• bind is temporary
• effect is overcome by high substrate concentration
• so maximum rate can be achieved

Question 7

what are non competitive inhibitors?

Answer 7

• attach to a binding site which is not active site so doesn’t compete with substrate
• causes distortion to active site
• so substrate no longer complementary to active site so no ES complexes form
• maximum rate can’t be achieved as effect of inhibitor isn’t reversible