enzymes - unfinished.

Question 1

What is a competitive inhibitor?

Answer 1

An inhibitor that competes with the substrate molecules to bind to the active site.

Question 2

Explain competitive inhibition?

Answer 2

• Have a similar shape to substrate molecules.
• Competes with substrate molecules to bind to the active site first.
• Block the substrate molecules from the active site.

Question 3

What is a non-competitive inhibitor?

Answer 3

An inhibitor that binds away from the active site.

Question 4

Explain non-competitive inhibition?

Answer 4

• Bind to the enzyme away from the active site.
• This site is known as the allosteric site.
• This causes the active site to change shape so the substrate molecules can no longer bind to it.

Question 5

What is reversible inhibition?

Answer 5

The inhibitor does not bind permanently to the enzyme.

Question 6

What is non-reversible inhibition?

Answer 6

The inhibitor binds permanently to the enzyme.

Question 7

Why is an inhibition reversible?

Answer 7

If the bonds are weaker hydrogen bonds or weaker ionic bonds, the inhibitor can be removed easily.

Question 8

Why is an inhibition non-reversible?

Answer 8

If the bonds are strong covalent bonds, the inhibitor cannot be removed easily.

Question 9

What is product inhibition?

Answer 9

Where enzymes are inhibited by the product of the reaction they catalyse.

Question 10

What is a metabolic pathway?

Answer 10

A series of connected metabolic reactions. The product of the first reaction takes part in the second reaction.

Question 11

What is end-product inhibition?

Answer 11

When the final product in a metabolic pathway inhibits and enzyme that acts earlier on in the pathway.

Question 12

Why is end-product inhibition useful?

Answer 12

Regulates the pathway and for controlling the amount of end-product that gets made.

Question 13

Explain the induced fit hypothesis?

Answer 13

• The substrate is complementary to the active site and binds to it.
• Substrate has to be the right shape, and also has to make the active site change shape in the right way.
• As the substrate binds, the active site changes shape slightly.

Question 14

Explain the lock-and-key hypothesis?

Answer 14

• The substrate is complementary to the active site and binds to it.
• Enzyme-product complex is formed when the substrate has been converted into it’s products.
• Products are released, enzyme is unchanged.