Enzymes

Question 1

Competitive Inhibitor: Vmax ____ while Km ___ (dec, same, inc)

Answer 1

Competitive Inhibitor Vmax same, Km increased

Question 2

Noncompetitive inhibitor: Vmax ____ while Km ___ (dec, same, inc)

Answer 2

Noncompetitive Inhibitor: Vmax decreased, Km same

Question 3

_____ enzymes bind at sites other than the active site

Answer 3

Allosteric enzyme

Question 4

____ enzymes catalyze the same reaction but has different amino acid sequence

Answer 4

Isoenzymes (i.e. lactate dehydrogenase, CK)

Question 5

Enzymes ____ (inc, reduces) the Gibbs free energy by ___ (inc, dec) the energy activation

Answer 5

Enzymes do not affect the Gibbs free energy by lowering the EA

Question 6

In the Lineweaver-Burk plot, the slope suggests

Answer 6

Km/Vmax

Question 7

___ are physically distinct versions of a given enzyme (each of which catalyzes the same reaction)

Answer 7

isozymes

Question 8

What is the isozyme of hexokinase

Answer 8

glucokinase

Question 9

[Class of Enzyme]

add oxygen

Answer 9

Oxidoreductase

1. Oxidase

Question 10

[Class of Enzyme]

add hydrogens

Answer 10

Oxidoreductase

1. Reductase

Question 11

[Class of Enzyme]

remove hydrogen

Answer 11

Oxidoreductase

1. Dehydrogenase

Question 12

[Class of Enzyme]

move chemical groups from one substrate to another

Answer 12

Transferase

Question 13

[Class of Enzyme]

cleave substate bond using water

Answer 13

hydrolase

Question 14

[Class of Enzyme]

rearrange substrate

Answer 14

Isomerase

Question 15

[Class of Enzyme]

joins substrate forming new bonds

Answer 15

synthase

Question 16

[Class of Enzyme]

remove phosphate group

Answer 16

phosphatase

Question 17

[Class of Enzyme]

add phosphate groups to substrate

Answer 17

phosphorylase and kinase

Question 18

What bond holds the substrate to the active site in the enzyme

Answer 18

hydrogen bonds

Question 19

___ are transient, dissociable either to the enzyme or to a substrate; made of vitamins

Answer 19

cofactor

Question 20

___ serve as recyclable shuttles that transport many substrates from point A to point B; made of proteins

Answer 20

coenzyme

Question 21

____ equation describes how reaction velocity varies with substrate concentration

Answer 21

Michaelis-Menten Equation

Question 22

What are the different assumptions in Michaelis-Menten Equation

Answer 22

1. [S] > [E]
2. [ES] is constant
3. [P] is low

Question 23

What is the curve of the michaelis-mentin kinetics?

Answer 23

curve

Question 24

Once the enzymes are saturated, the velocity of the reaction ___ ( increases, decreases, same)

Answer 24

Remains the same

Zero order

Question 25

____ refers to the maximal number of substrate molecules converted to product per unit time

Answer 25

maximal velocity

Question 26

___ refers to the substrate concentration at which Vi is half the maximal velocity attainable at a particular concentration of enzyme

Answer 26

Michaelis Constant

Question 27

What are the factors that affect the rate of a reaction

Answer 27

1. Substrate concentration 2. Temperature 3. pH

Question 28

____ is the reciprocal of the Michaelis-Menten equation

Answer 28

Lineweaver burk

Question 29

This graph is used to calculate the Km and Vmax

Answer 29

Lineweaver-burk

Question 30

The slope of the lineweaver burk plot is equivalent to

Answer 30

slope (m) = Km/Vmax

Question 31

The x-intercept of lineweaver-burk plot refers to the

Answer 31

x intercept = -(1/Km)

Question 32

The y-intercept of lineweaver-burk plot refers to the

Answer 32

y intercept = (1/Vmax)

Question 33

[Enzyme inhibitor] shape is similar to the substrate and competes for the binding site

Answer 33

competitive

Question 34

[Enzyme inhibitor] competitive inhibitor can be reversed by?

Answer 34

Increasing the [S]

Question 35

[Enzyme inhibitor] an inhibitor that binds other than the active site

Answer 35

non-competitive inhibitor

Question 36

[Enzyme inhibitor] to reverse non-competitive inhibitors,

Answer 36

increase [E]

Question 37

Enzyme activity can be regulated by

Answer 37

1. Change in substrate concentration 2. Allosteric binding site 3. Covalent modification 4, Induction and repression of enzyme synthesis

Question 38

[Regulation of enzyme activity] ___ effectors in the allosteric binding sites when the substrate itself serves as an effector

Answer 38

Homotropic effector

Question 39

[Regulation of enzyme activity] ___ effectors in the allosteric binding sites the effector is different from the substrate

Answer 39

heterotropic effectors

Question 40

Induction and repression of enzyme synthesis happens in what part of the central dogma?

Answer 40

Transcription

Question 41

[Clinical Correlate: Identify the disease] ceruloplasmin

Answer 41

Wilson disease

Question 42

[Clinical Correlate: Identify the disease] beta-glucocerebrodase

Answer 42

Gaucher