3.5 Factors affecting enzyme action

Question 1

What does denatured mean

Answer 1

the shape of an enzymes active site is changed by high temperatures or an extreme pH, so it can no longer bind with the substrate

Question 2

What’s the optimum temperature for human enzymes

Answer 2

37 degrees (human body temperature)

Question 3

What happens the temperature is too low?

Answer 3

• Reaction rate is low
• Enzymes have too little kinetic energy and move slowly
• Few successful collisions between substrate and enzyme lead to low rate of reaction

Question 4

What happens when an enzyme is at its optimum temperature

Answer 4

• Reaction rate is high
• Enzymes have a lot of kinetic energy and move quickly
• Lots of frequent successful collisions between enzyme and substrate lead to high rate of reaction

Question 5

What happens when an enzyme is at a high temperature

Answer 5

• Reaction rate is low
• Heat breaks the bonds maintaining the tertiary structure of the enzyme
• The active site becomes denatured and the substrate no longer fits
• No successful collisions lead to low rate of reaction

Question 6

What happens when an enzyme is at a low pH

Answer 6

• reaction rate is low
• acidity breaks the bonds maintaining the tertiary structure of the enzyme
• the active site becomes denatured and the substrate no longer fits
• no successful collisions lead to low rate of reaction

Question 7

What happens when an enzyme is at the optimum pH

Answer 7

• reaction rate is high
• frequent successful collisions between enzyme and substrate leads to high rate of reaction

Question 8

What happens when an enzyme is at a high pH

Answer 8

• reaction rate is low
• alkalinity breaks the bonds maintaining the tertiary structure of the enzyme
• the active site becomes denatured and the substrate no longer fits
• no successful collisions lead to low rate of reaction

Question 9

What happens when the substrate concentration is low

Answer 9

• Low rate of reaction
• Few substrate molecules limit the chances of successful collisions between enzyme and substrate

Question 10

What happens when substrate concentration is high

Answer 10

• rate of reaction is high
• more substrate molecules lead to more frequent successful collisions between enzyme and substrate

Question 11

Why does the substrate concentration graph not keep going up

Answer 11

Because eventually all active sites are occupied by substrate molecules (saturates)

Question 12

What are the 3 factors affecting enzyme function

Answer 12

Temperature, pH, substrate concentration