2.1.4 Enzymes

Question 1

What are enzymes?

Answer 1

Biological catalysts that can speed up the rate of a reaction in the body.

Question 2

Enzymes provide…

Answer 2

Alternate pathways by reducing the activation energy of the reaction.

Question 3

What is activation energy?

Answer 3

Activation energy is the minimum amount of energy needed for a reaction to start

Question 4

Enzymes reduce the amount of activation energy needed; this means that…

Answer 4

Reactions can happen at lower temperatures
(most bodily reactions would not be possible at body temp if not for enzymes)

Question 5

After a reaction enzymes remain…

Answer 5

Unchanged; can be reused

Question 6

What are the 2 types of enzymes?

Answer 6

Extracellular
Intracellular

Question 7

Intracellular enzymes

Answer 7

Found in the cell e.g. RNA Polymerase, DNA helicase etc.

Question 7

Extracellular enzymes:

Answer 7

Found outside of cells e.g. Amylase

Question 8

Enzymes are…

Answer 8

Globular Proteins

Question 9

Globular proteins are…

Answer 9

Spherical (quaternary structure)
Easily soluble and can be transported easily (e.g. blood etc.)
It can denature if pH and temperature deviate from the optimum.

Question 10

Enzymes have…

Answer 10

Active sites (with specific shapes)

Question 11

The shape of the active site is complementary to …

Answer 11

the shape of the substrate

Question 12

What is the name of the additional binding regions some enzymes have

Answer 12

Allosteric site (alternative site)

Question 13

Allosteric sites are only occupied by mainly?

Answer 13

non-competitive inhibitors

Question 14

What are the 2 models/theories for enzyme action?

Answer 14

Lock and Key model/theory
Induced fit model/theory

Question 15

Lock and Key Theory:

Answer 15

1. Substrate binds to enzyme’s active site (complementary); Enzyme-substrate complex formed
2. E-P complex then forms in the enzyme’s active site
3. Products are then released from the active site

Question 16

Induced fit Theory:

Answer 16

Only occurs when the shape of the enzyme active site and substrate are not entirely complementary.

1. Substrate enters the enzyme’s active site (ES complex)
2. Enzymes undergo a conformational change, which allows the active site of the enzyme to be complementary to the substrate.
3. This induces the formation of an EP complex
4. Products are then released by the active site