Factors Affecting Enzyme Activity

Question 1

Explain why an increase in temperature increase the rate of enzyme activity

Answer 1

At higher temperatures the molecules have more kinetic energy, so they move faster. This makes the substrate molecules more likely to collide with the enzymes active site. The energy of these collisions also increase, which means each collisions is more likely to result in reaction.

Question 2

Explain how a very high temperature can stop an enzyme working.

Answer 2

A very high temperature makes the enzymes molecules vibrate more. This vibration breaks some of the bonds that hold the enzyme in shape. The active site changes shape and the enzyme and substrate no longer fit together. THE ENZYME IS DENATURED

Question 3

What happens to an enzymes shape and function when in its denatured

Answer 3

The bonds that hold the enzyme in shape are broken. This smears the shape of the active site meaning it is no longer a complementary scale to the substrate. The enzyme can’t catalyse the reaction.

Question 4

Give a factor other than temperature that can denature an enzyme

Answer 4

PH

Question 5

What is meaner by the saturation’ point’ in an enzyme in an enzyme controlled reaction

Answer 5

The point at which the all the active sites are occupied by substrate molecules

Question 6

Explain what happens to the rate of an enzyme-controlled reaction when the substrate concentration is increased after the saturation point

Answer 6

The rate of reaction stays constant. All the active sites are occupied so increasing the substrate concentration has no effect

Question 7

Explain the effect of increasing the enzyme concentration on the rate of an enzyme controlled reaction.

Answer 7

At first, increasing the enzyme concentration increases the rate of reaction. This is because the more enzyme molecules there are in a solution, the more likely a substrate molecule is to collide with an active site and form an enzyme-substrate complex. The rate of reaction continues to increase until the substrate concentration becomes a limiting factor. At this point the rate of reaction levels off.

Question 8

Where do the following molecules bind to an enzyme.
a) an non-competitive inhibitor
b) a competitive inhibitor

Answer 8

a) away from the active site
b) at the active site

Question 9

Explain how non-competitive inhibition prevents the enzyme activity

Answer 9

A non-competitive inhibitor molecule binds to the enzyme away from the active site. Its presence alter the shape of the active site meaning that substrate molecules can no longer bind here. This prevents enzyme activity