Enzymes Part 1

Question 1

What is an enzyme?

Answer 1

Proteins that acts as biological catalysts that exhibit a very high degree of specificity

Question 2

What is a catalyst?

Answer 2

Any chemical that can speed up a chemical reaction without itself being changed

Question 3

How do catalysts work?

Answer 3

They change the kinetics of a reaction by providing a faster reaction pathway

Question 4

What do catalysts do to the activation energy?

Answer 4

Lowers it

Question 5

Describe the process of enzyme catalysis

Answer 5

Enzyme and substrate combine to form complex
ES complex formed
Enzyme and product separate

Question 6

Describe 5 things that enzymes provide and do in enzyme catalysis

Answer 6

-Provide reaction surface and suitable environment
-brings reactants together and position them correctly so they attain transition state
-weakens bonds in reactants
- may participate in reaction
-form stronger interactions with the transition state than with the substrate or product

Question 7

Where is the active site

Answer 7

In the cleft

Question 8

True or false: A catalyst changes the overall energy of the reaction

Answer 8

False

Question 9

True or False: A catalyst gets there faster but does not change the equilibrium

Answer 9

True

Question 10

What’s a transition state

Answer 10

Is an unstable high-energy state- has the structure of between the reactant and the product

Question 11

What is ES complex also called

Answer 11

Enzyme intermediate

Question 12

Whats an active site

Answer 12

provides a specific environment in which a given reaction can occur more rapidly

Question 13

whats an substrate

Answer 13

The molecule that is bound to the active site and acted upon by the enzyme

Question 14

What do many enzymes use in a reaction

Answer 14

ATP

Question 15

Where does the equilibrium lie for the ATP reaction

Answer 15

well to the right

Question 16

Whats the basic reaction for ATP

Answer 16

ATP-> ADP+Pi+ energy

Question 17

What’s the diffusion controlled limit?

Answer 17

This is the rate at which molecules can get to the enzyme

Question 18

What’s the equation of the process of alcohol degradation

Answer 18

CH3CH2OH—> CH3CHO——–>CH3COOH
(ethanol) (acetaldehyde:toxic) (acetic acid)

Question 19

What enzymes are used in order for the degradation of alcohol?

Answer 19

1-alcohol dehydrogenase (faster )
2- aldehyde dehydrogenase

Question 20

What’s a cofactor?

Answer 20

An extra (non-protein) part of an enzyme chemically unchanged by the reaction

Question 21

What’s a Holoenzyme?

Answer 21

An active enzyme consisting of the apoenzyme and coenzyme

Question 22

Whats an apoenzyme?

Answer 22

The protein part of an enzyme that’s inactive on it’s own but becomes active with it’s required cofactor

Question 23

What’s a coenzyme

Answer 23

The dis-sociable, low-relative molecular mass active group of an enzyme which transfers chemical groups such as hydrogen or electrons

Question 24

What affects enzyme activity

Answer 24

1- environmental conditions
2 cofactors and Coenzymes
3 enzyme inhibitors

Question 25

What's Trypsin involved in?

Answer 25

digestion

Question 26

What's a catalytic triad?

Answer 26

specific group of 3 amino acids residues in the active site of an enzyme that work together to facilitate the enzymes catalytic activity

Question 27

What 3 amino acids are in the catalytic triad?

Answer 27

Serine Histidine Aspartate

Question 28

What's the role of each amino acid in the catalytic triad?

Answer 28

Serine- acts as a nucleophile forming a strong bond with the substrate Histidine- acts as a base helps deprotonate serine activating it for nucleophilic attack on substrate Aspartate- stabilises positive charge that forms on His to form functionally as a base

Question 29

True or false: Enzymes are rigid

Answer 29

False