1.8 Factors affecting enzyme actions

Question 1

Which two factors affect enzymes?

Answer 1

temperature and pH

Question 2

How do temperature and pH affect enzymes?

Answer 2

1. they cause bonds to break, changing the enzyme’s tertiary structure
2. this causes the active site to change shape so that the substrate no longer fits
3. enzyme-substrate complexes can’t be formed
4. enzyme will be denatured and not working anymore

Question 3

Which four factors affect enzyme reactions?

Answer 3

1. temperature
2. pH
3. substrate concentration
4. enzyme concentration
5. concentration of inhibitors

Question 4

What will happen to the rate of reaction as the temperature increases?

Answer 4

Increase, because molecules have more kinetic energy, which causes more collisions and enzyme-substrate complexes.

Question 5

What will happen to the rate of reaction as it reaches to the optimum temperature?

Answer 5

It will reach to the maximum rate of reaction, because the optimum temperature is the temperature that enzyme works fastest at.

Question 6

What will happen to the rate of reaction as the temperature increases past the optimum?

Answer 6

Decrease, and the reaction will eventually stop, because there is too much kinetic energy, which causes the active site to change shape and the enzyme denatures.

Question 7

How is the rate of reaction when it is below the optimum pH?

Answer 7

The rate is low or zero, because in acidic conditions, H+ ions break ionic/hydrogen bonds and denature enzymes.

Question 8

How is the rate of reaction as it reaches to the optimum pH?

Answer 8

It will reach to the maximum rate of reaction, because the optimum pH is the pH that enzyme works fastest at.

Question 9

How is the rate of reaction when it is above the optimum pH?

Answer 9

The rate is low or zero, because in alkaline conditions, OH- ions break ionic/hydrogen bonds and denature enzymes.

Question 10

What will happen to the rate of reaction as the substrate concentration increases?

Answer 10

Increase, because there are more substrate molecules, which increases the rate of collisions, so there will be more successful collisions.

Question 11

What will happen to the rate of reaction as the substrate concentration increases further?

Answer 11

The rate will be level off, because it reaches the saturation point, which is when all active sites are occupied by a substrate and enzyme concentration will become the limiting factor.

Question 12

What will happen to the rate of reaction as the enzyme concentration increases?

Answer 12

Increase, because there are more enzyme molecules, which increases the rate of collisions, so there will be more successful collisions.

Question 13

What will happen to the rate of reaction as the enzyme concentration increases further?

Answer 13

The rate will be level off, because all substrate molecules available are being used and substrate concentration will become the limiting factor.