Enzymes

Question 1

What are oxidoreductases

Answer 1

Enzymes that catalyze the transfer of electrons

Question 2

What are transferases

Answer 2

Enzymes that catalyze the transfer of functional groups

Question 3

What class of enzymes use water to break a covalent bond

Answer 3

Hydrolases

Question 4

What are lyases

Answer 4

Enzymes that catalyze the breaking of covalent bonds

Question 5

What enzyme reaction can lead to the formation of new bonds

Answer 5

Lyases

Question 6

What are isomerases

Answer 6

Enzymes that convert a molecule from one isomer to another

Question 7

What are ligases

Answer 7

Enzymes that catalyze the joint of two molecules by forming a new bond

Question 8

What is a substrate

Answer 8

A molecule that an enzyme reacts with

Question 9

What is enzyme-substrate complex

Answer 9

A reversible association between an enzyme and substrate

Question 10

Where does catalysis occur

Answer 10

Enzyme-substrate complex

Question 11

Active site

Answer 11

The pocket on the enzymes where the substrate binds and the reaction takes place

Question 12

An example of a substrate

Answer 12

ATP

Question 13

Why is an uncatalyzed reaction rate slower

Answer 13

It doesn’t possess a catalyst so the activation energy is larger thus making the rate slower

Question 14

Where is the highest energy point in an uncatalyzed reaction

Answer 14

The transition state

Question 15

What does an uncatalyzed reaction look like

Answer 15

S->S*->P

Question 16

An enzyme catalyzed reaction look like

Answer 16

S+E->E.S->E.S*->E.P->E+P

Question 17

Explain the transition state theory

Answer 17

The rate of a chemical reaction depends on how much energy a substrate can acquire to reach its transition state

Question 18

Why does S* have a higher energy than S

Answer 18

Because S* undergoes bond stretching or bending in order to react(distortion)

Question 19

What type of reactions are formed when E binds to S

Answer 19

Hydrogen bonds
Hydrophobic interactions(Van der waals)

Question 20

What are some effects of the E.S formation

Answer 20

Decrease in entropy of S
Desolvation (removal of H2O shell around S)
Induced fit: the enzyme adjusts to the shape of S*
Alignment of groups that must react

Question 21

How does an enzyme recognize and binds a substrate

Answer 21

Shape consistency(the substrate must fit the active site)
Electrostatic consistency(correct matching of H-bonds and ionic within the active site
Thermodynamic consistency: can the protein flex to adopt a substrate or the substrate flex to fit active site