1.9 Enzyme inhibition

Question 1

What is a competitive inhibitor

Answer 1

The are the same shape as the substrate and can bind to the active site.This prevents the substrate from binding and the reaction from occuring

Question 2

What happens if you add more substrates to a competitive inhibitor

Answer 2

The substrates will out compete the inhibitors knocking them out of the active site

Question 3

What is a inhibitor

Answer 3

A molecule that binds somewhere on the enzyme preventing it form functioning

Question 4

What is a non competitive inhibitor

Answer 4

A type of inhibitor where it binds to an enzyme away from the active site
This causes the active site to change shape and therefore the substrate can no longer bind regardless of how many substrates are present/added

Question 5

Describe and explain the effect of concentration of competitive inhibitors on the rate of enzyme-controlled reactions (6)

Answer 5

● As concentration of competitive inhibitor increases, rate of
reaction decreases
○ Similar shape to substrate
○ Competes for / binds to / blocks active site
○ So substrates can’t bind
○ So fewer enzyme-substrate complexes form
● Increasing substrate concentration reduces effect of inhibitors
(dependent on relative concentrations of substrate and inhibitor)

Question 6

Describe and explain the effect of concentration of non-competitive inhibitors on the rate of enzyme-controlled reactions (7)

Answer 6

● As concentration of non-competitive inhibitor increases, rate of reaction decreases
○ Binds to site other than the active site (allosteric site)
○ Changes enzyme tertiary structure / active site shape
○ So active site no longer complementary to substrate
○ So substrates can’t bind
○ So fewer enzyme-substrate complexes form
● Increasing substrate concentration has no effect on rate of
reaction as change to active site is permanent

Question 7

When an enzyme/protein dentaures what happens

Answer 7

The IONIC and HYDROGEN bonds break and the tertiary structure changes

Question 8

Is the shape of a substrate complimentary to a competitive inhibitr

Answer 8

NOOO they are similar but not teh same

Question 9

A competitive inhibitor decreases the rate of an enzyme-controlled reaction. Explain how.

Answer 9

1. Inhibitor similar shape to substrate;
2. Fits/binds to active site;
3. Prevents/reduces enzyme-substrate complex forming;

Question 10

Are competetive inhibitors the same shape as substartes

Answer 10

They are similar