SB1h - Enzyme Activity

Question 1

State the 4 factors that affect enzyme activity.

Answer 1

 Temperature
 pH
 Enzyme concentration
 Substrate concentration

Question 2

Explain why enzymes decrease in reactivity when they aren’t at their optimum temperature.

Answer 2

• At low temperature
  molecules move slower
  (have less kinetic energy)
• At optimum temperature
  they work the fastest – more
  enzyme substrate
  complexes form as they
  gain kinetic energy
• Above optimum temperature
  they start to denature
  (active site changes shape)
  so activity decreases, until all
  enzymes are denatured and
  enzyme activity drops to 0

Question 3

Explain why rate of reaction increases as substrate concertation increases but stops after a while.

Answer 3

As substrate concentration
increases, rate of reaction increases
too as more product is produced

• But if substrate increases too much,
  there will not be any free active
  sites to bind with substrate
  molecules.
• So the enzymes are working at their
  maximum speed and the rate of
  reaction becomes constant