Chapter 7- Enzymes (2)

Question 1

Describe what occurs during competitive inhibition?

Answer 1

These inhibitor molecules compete with the substrate molecules for access to the active site of an enzyme.

When inhibitor molecule bind to the active site of an enzyme, it blocks any substrates binding to it which means a chemical reaction cannot occur.

Question 2

Having competitive inhibitor molecules will do what to the km and Vmax?

Answer 2

Km and the Vmax remains constant as we increase substrate concentration.

Question 3

What is required to reach the Vmax?

Answer 3

An increase in substrate concentration

Question 4

Describe what occurs during non-competitive inhibition?

Answer 4

This is when the inhibitor binds to the enzyme away from the active site which changes the whole shape of the enzyme.

This means its complementary substrate will not be able to bind to it to form a chemical reaction, which means no chemical reaction can take place.

A substrate is still able to bind to the enzyme, but a chemical reaction can only take place if the inhibitor is removed from the enzyme.

Question 5

What does the non competitive inhibitor do to the Km constant and the Vmax?

Answer 5

Keeps the Km constant and decreases the Vmax.

Question 6

What happens if you increase the substrate concentration while non competitive inhibitor molecules are present?

Answer 6

Increasing substrate concentration will have no effect.

Question 7

What are the different ways to regulate an enzyme?

Answer 7

1- Activation of a zymogen (precursor)- that is inactive and is activated once a portion is cleaved off. Cleavage reveals the active site allowing the enzyme to become active and function to catalyze reactions.

2- Reversible phosphorylation- Phosphate groups are often phosphorylated to inactivate an enzyme.

3- Competitive product inhibition- When the product of a catalysed reaction act as inhibitors back onto that enzyme.