C4 Enzymes

Question 1

What are enzymes ?

Answer 1

Proteins with are biological catalysts and hence can speed up chemical and metabolic reactions by lowering the activation energy.

Question 2

Facts about the active site:

Answer 2

• Binds to the substrate
  -complementary to substrate shape (specific)

Question 3

What are the two models for enzymes we need to know?

Answer 3

-lock and key model
-induced fit

Question 4

What is the difference between the two models of enzymes we know?

Answer 4

• the first one is the lock and key theory which is where the enzyme will have a set active site and will somehow need to fit in the substrate , this is very rigid and requires perfect collisions which is very hard
• However, then the induced fit was suggested which is where the enzyme active site can change slightly to fit the substrate

Question 5

What are intercellular enzymes ?

Answer 5

Intracellular enzymes are found inside cells and are responsible for processing food inside the cell

Question 6

Example of an intercellular enzymes

Answer 6

Catalase

Question 7

What is an extracellular enzyme?

Answer 7

Extracellular enzymes, on the other hand, are located outside of cells and are used to interact with other molecules outside of the cell

Question 8

Examples of an extracellular enzyme

Answer 8

1) Amylase (starch to maltose)
2) Trypsis (protein to amino acids)

Question 9

Factors that affect enzymes activity

Answer 9

1) Temperature
2) PH
3) Substrate/enzymes concentration

Question 10

How does temperature affect enzyme activity

Answer 10

Kinetic energy increases, molecules move quicker , higher chance of the active site of the enzymes to and substate to collide with one another therefore increase the rate of reaction

Question 11

In a enzyme temperature rate graph what are the different parts called

Answer 11

1- low temperature =enzymes are inactive, rate is slow, low kinetic temperature
2-optium temperature , maximum rate of reaction (vmax)
3- rate will drop, enzymes are denatured (loss of active site), active site is destroyed,

Question 12

What is Q10 in enzymes?

Answer 12

The Q10 temperature coefficient is a measure of temperature sensitivity based on the chemical reactions.
Every 10 degrees
EG: Q10=2, every 10 degrees temperature will double…

Question 13

How does PH become acidic or alkaline ?

Answer 13

Higher the PH, lower the H+ or Proton concentration, alkaline and vice versa

Question 14

What are enzyme inhibitors?

Answer 14

The inhibitor molecule, which has a similar shape to the substrate molecule, competes with the substrate to bind to the active site of an enzyme

Question 15

What are the two different sites on an enzyme?

Answer 15

-Active site (top)
-Allosteric site (bottom)

Question 16

What is the difference between an active site and allosteric site?

Answer 16

Active site is at the top and that is where the substrate bind, allosteric site is where any other thing can bind and is at bottom

Question 17

What are the two types of inhibitors?

Answer 17

-competitive-> Goes to the active site and compete with the substrate with the active site- the active site does not change shape
-non-competitive- binds to a site other than the active site, not competing for the active site, causes structural change to the active site

Question 18

What does increasing substrate do to competition inhibition?

Answer 18

Competitive inhibition can be overcome by increasing the concentration of substrate as there will be a higher chance of collisions and the substrate will out number the completion inhibitors

Competition inhibitors have a similar structure to substrate hence they compete for the same active site. Less active sites available means less enzymes substrate complexes formed meaning less rate.

Question 19

What does increasing substrate do to Non-competitive inhibition?

Answer 19

• doesent affect the rate
• Noncompetitive inhibition, however, cannot be easily overcome by substrate concentration because the inhibitor binds to a site other than the active site
  -higher substrate can not restore VMAX
  -the only way to restore the vmax is to remove the non competitive inhibitor

Question 20

What are cofactors?

Answer 20

A cofactor is a non- protein chemical compound that is bound to a protein and is required for the protein’s biological activity

Question 21

What are enzymes first called when they are produced and what do they mean?

Answer 21

Apoenzymes -inactive form of the enzyme , cant catalyse any enzyme , they then turn to holoenzyme , when they change the tertiary structure

Question 22

How can we make a holoenzyme from an apoenzyme ?

Answer 22

-its is a increases in activation , basically is a change in tertiary (3D structure)

Question 23

How do we activate an apoenzyme into a holoenzyme? (3)

Answer 23

1- use of another enzyme
2- change in surrounding condition (EG: Temp and PH)
3-Cofactors

Question 24

What is the Q10 formula?

Answer 24

rate at higher temperature/rate at lower temperature

Question 25

What does an reversible and non-reversible inhibitor do ?

Answer 25

A reversible inhibitor inactivates an enzyme through noncovalent, reversible interactions

An irreversible inhibitor inactivates an enzyme by bonding covalently to a particular group at the active site

Question 26

Why are cofactors and coenzymes needed and examples of them

Answer 26

for oxidation-reduction reaction and group transfer processes which are not facilitated by functional groups of proteins.

Cofactors = chloride ion
Coenzyme = Amylase and vitamins