Enzymes Revision Carousel

Question 1

The active site has a ___ shape to the substrate.

Answer 1

Complementary/Specific

Question 2

Define the term ‘denaturation’.

Answer 2

Loss of Active Site Shape

Question 3

Explain how an increase of temperature increases enzyme activity.

Answer 3

-Increases particles’ kinetic energy
-Particles move faster and collide more often
-More successful collisions between AS and substrate

Question 4

Explain how high temperatures can denature enzymes.

Answer 4

-Leads to more vibrations
-Too much vibration breaks the bonds that hold the protein together

Question 5

What is the temperature coefficient (Q10)?

Answer 5

A measure of how much the reaction rate increases with a 10oC increase

Question 6

How does a change in pH affect enzymes structure?

Answer 6

-A change in pH refers to change in H+ concentration
-H+ ions interact with polar and charged R groups in tertiary structure
-This breaks the bonds/interactions between R groups, leading to loss of tertiary structure

Question 7

Explain why can increase in substrate concentration increases rate of reaction.

Answer 7

-Higher successful collision rate
-Between active site and substrate
-Forming more enzyme-substrate complexes

Question 8

Explain the difference between competitive and non-competitive mechanisms.

Answer 8

C-inhibitory binds to active site so substrate can no longer bind to AS
NC-inhibitor binds to alternative location than the active site (allosteric site) meaning changes 3D structure hence the change in AS

Question 9

State the difference cofactors and coenzymes.

Answer 9

CF-Non protein component to help enzymes carry out their functions
CE-organic cofactors

Question 10

Why is it important that some enzymes are produced in its inactive form?

Answer 10

May damage cell it was produced in

Question 11

What are enzymes?

Answer 11

Biological Catalyst that speed up chemical reactions

Question 12

What is the difference between the lock-and-key model and the induced fit model?

Answer 12

L&K-rigid, no movement
IF-slight movement of AS to allow better binding to substrate

Question 13

Name and extracellular enzyme.

Answer 13

Amylase/Trypsin

Question 14

Most competitive inhibitors are reversible or irreversible?

Answer 14

Reversible

Question 15

What is end-product inhibition?

Answer 15

The product of an enzyme-catalysed reaction acts as the inhibitor

Question 16

Name the prosthetic group in carbonic anhydrase.

Answer 16

ZN2+

Question 17

What are the 3 ways that an enzyme can be activated by changing the tertiary structure?

Answer 17

-Adding a cofactor
-Action of another enzyme
-Change on condition

Question 18

What are the enzymes’ effect on the activation energy of a reaction?

Answer 18

Enzymes lower Ea

Question 19

What does it mean by a ‘reversible’ inhibitor?

Answer 19

Inhibitor can be released from the enzyme to resume the enzymes function

Question 20

Explain how Vmax of the enzyme can be unchanged in competitive inhibition.

Answer 20

-Adding more substrates to out compete inhibitors
-More substrates leads to more successful collisions between enzymes and substrates so more ESC formed
-Therefore less enzymes available for enzymes to bind

Question 21

What type of inhibitor does aspirin belong to?

Answer 21

Irreversible, Competitive

Question 22

Explain how an increase in substrate concentration affects the rate of reaction in non-competitive inhibition.

Answer 22

No change as active site is altered by the inhibitor binding in the allosteric site

Question 23

What is a holoenzyme?

Answer 23

An active form of an enzyme

Question 24

State the difference between cofactors and prosthetic groups.

Answer 24

CF-temporarily bound to enzyme
PG-permanently bound to enzyme

Question 25

From which chemical are coenzyme’s derived from?

Answer 25

Vitamins

Question 26

What are catabolic reactions?

Answer 26

Breaking down molecules

Question 27

Name the prosthetic group in haemoglobin.

Answer 27

Iron ion in haem group

Question 28

What is an apoenzyme?

Answer 28

Inactive form of an enzyme

Question 29

What is the difference between the lock-and-key model and the Induced fit model?

Answer 29

L&K-Rigid, no movement
IF-Slight movement of active site to allow better binding substrate