Factors Affecting Enzymes

Question 1

What are the 5 factors affecting enzymes?

Answer 1

pH
Temperature
Enzyme concentration
Substrate concentration
Inhibitors

Question 2

What happens when temperature is too low?

Answer 2

Not enough kinetic energy for successful collisions between enzyme and substrate.

Question 3

What happens when temperature is too high?

Answer 3

Enzymes denature and the active site changes shape and the enzyme-substrate complex can’t form.

Question 4

What happens when there is too much kinetic energy?

Answer 4

The bonds holding the amino acids in their fixed 3D tertiary structure in the active site are going to be broken down because of the increase in temperature.

Question 5

What makes pH too high?

Answer 5

Too many H+ ions.

Question 6

What makes pH too low?

Answer 6

Too many OH- ions.

Question 7

Do all enzymes have the same optimal pH?

Answer 7

No.

Question 8

What happens if pH is too high or too low?

Answer 8

It’ll interfere with the charges in the amino acids in the active site. This can break the bonds that hold the tertiary structure in place and thus the active site changes shape. Thus the enzyme denatures and fewer enzyme-substrate complexes form.

Question 9

What happens if there is insufficient substrate?

Answer 9

The reaction will be slower as there will be fewer collisions between the enzyme and the substrate. Thus there will be fewer enzyme-substrate complexes.

Question 10

What is the limiting factor of insufficient substrate?

Answer 10

Enzymes are the limiting factor.

Question 11

What happens if there is sufficient enzymes?

Answer 11

The enzyme active sites will become saturated with substrates and become unable to work any faster.

Question 12

Why are there empty active sites?

Answer 12

There are more enzymes than substrates.

Question 13

What is the limiting factor of sufficient enzymes?

Answer 13

Empty active sites.

Question 14

What are the two inhibitors?

Answer 14

Competitive Inhibitor
Non-competitive Inhibitor

Question 15

What is an inhibitor?

Answer 15

A molecule which binds somewhere on the enzyme and thus prevents the enzyme from functioning.

Question 16

What is a competitive inhibitor?

Answer 16

When the molecule is the same shape as the substrate or very similar in shape but not identical and thus it is also complementary to the active site. It is able to bind and thus we get an enzyme-inhibitor complex. This prevents the substrate from being able to bind and thus you won’t get any enzyme-substrate complexes and the reaction will be much slower or won’t occur.

Question 17

What is a non-competitive inhibitor?

Answer 17

The non-competitive inhibitor binds away from the active site. It can bind to any location that its complementary to that is not the active site. This is called the allosteric site.

Question 18

What happens when the non-competitive inhibitor binds?

Answer 18

It slightly changes the tertiary structure and thus the active site slightly changes shape. The substrate is then no longer complementary to the active site. Even if it collides it won’t form an enzyme-substrate complex.