CHAPTER 6

Question 1

BIOLOGICAL CATALYST

Answer 1

ENZYME

Question 2

INCREASE RATE OF RXN 10^20

Answer 2

ENZYME

Question 3

CATALYZE ONLY ONE STEREOISOMER OTHERS FAMILY OF REACTIONS

Answer 3

ENZYME

Question 4

ALL ENZYMES ARE PROTEINS

Answer 4

ALL ENZYMES ARE PROTEINS

Question 5

Rate of Rxn depends on

Answer 5

Activation Energy DG

Question 6

Provides an alternative pathway with a lower activation Energy

Answer 6

Enzyme

Question 7

The free Energy of Activation are the
Free Energy of Change

Answer 7

Arrow under the parabola
Arrow under the Free Energy of Activation

Question 8

Free Energy of Activation Catalyzed reaction is
Free Energy of Activation Uncatalzyed rxn is

Answer 8

Much Less/ Less than the
Greater

Question 9

Most Important Function of Proteins is
Performed by the

Answer 9

Catalysis
Protein, Enzyme

Question 10

Enzyme Activity Decreases because of

Answer 10

Thermal Denaturation

Question 11

Two models for Binding of Substrate to an Enzyme:

Answer 11

Lock and Key Model
Induced Fit Model

Question 12

Complementary Shape of the Substrate and The Binding Site/ Portion of the Enzyme

Answer 12

Lock and Key Model

Question 13

Induces Changed after the Substrate Binds to the Active Site Resulting in Complementary change of the active site and the substrate

Answer 13

Induced Fit Model

Question 14

What Occurs After Enzyme Transition Complex is Formed

Answer 14

Catalysis Occurs

Question 15

In the complex, S is bound to the enzyme with correct orientation with respect to the atoms it is to react with
Both Proximity and Orientation _______
Substrate + Enzyme Forms —–>

Answer 15

Speed Up the Reaction
Product + Enzyme —–> Product is released into
Enzyme + Product

Question 16

Enzyme Catalyze Reaction Example is
It: Cleaves
Catalyzes Hydrolysis of

Answer 16

Chymotrypsin
Lys, His, Gln
Peptide bonds

Question 17

Hydrolysis of P-nITROPHENYL Ester by Chymotrypsin
Rate is _________ on Substrate
At _____ (S) rxn rate increase with _____ on (S)
At _____ (S) rxn rate changes very_____ and a _____ rate is reached
Graph is __________

Answer 17

Dependent
low, increase
Very Little
max
Hyperbolic

Question 18

ATCase- an _________
Similar to kinetic behavior of_______
Allosteric Proteins- Proteins in which subtle changes at one site affect the ________ and ________ at another site
_____________ and myoglobin are ____________

Answer 18

Allosteric Protein
Hemoglobin
Structure and Function
Chymotrypsin, Non allosteric Proteins

Question 19

ATcase-
_________ the reaction
Carbamoyl Phosphate +_________ —-> Carbamoyl Aspartate +
Leads to formation of CTP and UTP needed for biosynthesis of _____ and ______
Rxn rate depends on (S) which is _______
Graph is ________

Answer 19

Aspartate Transcarbamoylase
catalyzes
Aspartate
HPO42-
RNA AND DNA
Aspartate
Sigmoidal

Question 20

Michaelis-Menten Approach to Enzyme Kinetics
Full names: (1913, __________ and __________)
Basic Model for __________
Enzymatic Conversion the S——>___
Mechanism of Enzymatic Reaction:

Answer 20

Leonor Michaelis and Maud Menten
Nonallosteric Enzymes
P
E+S k-1<——>k1 ES —–>k2 E+P

Question 21

Solve for Concentration of Complex (ES)

Michaelis Menten Constant: Km

ES COMPLEX CONCENTRATION

Answer 21

(E) = (E)t -(ES) (E)t= Total (E)

(E)t-(ES)(S)/(ES) = Km

(E)t(S)/km+(S)

Question 22

If S Completely Saturates E (ES) = (E)t
If S saturates E

Answer 22

(ES) = (E)t
k2(E)t(S)/Km+(S)

Question 23

Michaelis Menten Equation:
When (S)=Km
When the Rxn rate is half of its max value,
the (S) conc. is
Km is only appropriate for Enzymes that Exhibit

Answer 23

V= Vmax(S)/Km+(S)
Vmax/2
Equal to Km
Hyperbolic Curve V vs (S)

Question 24

Linearizing Michaelis Menten Equation:
Equation For Hyperbola:
Equation For a Straight Line:

Answer 24

V=Vmax(S)/Km+(S)
1/V=Vmax(S)/Km+(S)= Km/Vmax+(S) +(S)/Vmax+(S)
1/V = Km/Vmax(S) + 1/Vmax

Question 25

Line Weaver Burk Double Reciprocal Plot: Gives Straight Line: Y and X Gives Slope: M Gives Intercept: B

Answer 25

1/V = Km/Vmax(S) x 1/(S) + 1/Vmax 1/V vs 1/(S) Km/Vmax(S) 1/Vmax

Question 26

Enzyme Inhibition: An _________ ,Is a substance that interferes with the _____ of and enzyme and ____ the rate of reaction An _______ is a substance that decreases the rate of an ___________ reaction

Answer 26

Inhibitor, Action, Slows Inhibitor, enzyme-catalyzed

Question 27

Reversible Inhibitor: A substance that ______ to an Enzyme it can inhibit but it can be ______

Answer 27

Binds, Released

Question 27

Competitive Inhibitor: Binds to the _____ site and ______ access to it by substrate Compete with the _______ for binding to the enzyme's ________ site Non-Competitive Inhibitor: _______ to a site other than the _____ site and inhibits enzyme by _______ its conformation Cannot be overcome by _________ substrate concentration Mixed Competitive: The binding of Inhibitor affects the binding of S, and Vice Versa Uncompetitive Inhibitors: Binds only to ES Complex preventing the Complex from releasing Products

Answer 27

Active, Blocks Substrate, Active Binds, Active, Changing Increasing

Question 28

Irreversible Inhibitor: A substance causes ________ that cannot be _________. Usually Involves the formation or breaking of covalent bonds to or on enzyme

Answer 28

Inhibition, Reversed

Question 29

Competitive Inhibition: EI <----> +I E <-----> +S ES <-----> E+P I = (I)/KI I/V=Km/Vmax (I+(I)/KI) x 1/(S) + 1/Vmax Km ________ because High S outcompetes I both vying at the same site, Vmax does not change.

Answer 29

Increases

Question 30

Competitive Inhibitor Non-Comp Site Binding: Change of Structure of E: Effect on Km: Effect on Vmax:

Answer 30

Active Site At a Site other than the Active Site No Yes Change No Change No Change Change

Question 30

Non-Competitive Inhibition: 1/V= Km/Vmax (I + (I)/KI) x 1/(S) +1/Vmax (I + (I)/Ki) Vmax _______ while Km remains _______ S does not overcome Noncomp I as they are not _______ for the same site

Answer 30

Decreases Constant Competing

Question 31

Enzyme Commission Classification and Nomenclature - __ MAJOR CLASSES Class. Sub Class, Sub-subclass, Specific Enzyme 1. Oxi 2. Trans 3.Hydro 4.Ly 5.Isome 6.Liga

Answer 31

6 Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases

Question 32

Catalyze oxidation-reduction reactions, electrons are --__________ from _____ molecule to another Example: Alcohol ______ EC (1.1.1.1)

Answer 32

Oxidoreductases Transferred, one Alcohol Dehydrogenase

Question 32

Transfer ___________ from one molecule to another Example: Hex_____ EC (2.__.__.1)

Answer 32

Transferases Functional Groups Hexokinase (2.7.1.1)

Question 33

Catalyze the ______ of Various bonds, Breaking molecules down using _______ Example: Lip_____ EC (__.__.1.__)

Answer 33

Hydrolases Hydrolysis, Water Lipase (3.1.1.3)

Question 34

Catalyze the ________ or ________ of groups to form double bonds or break double bonds without _______ or oxidation Example: ________ Decarboxylase EC (__.1.1.1)

Answer 34

Lyases Addition or Removal, Hydrolysis Pyruvate Decarboxylase (4.1.1.1)

Question 35

Catalyze the ________ of atoms within a molecule, facilitating _______ changes. Example: Phospho____ Isomerase EC (__.__.__.9)

Answer 35

Isomerases Rearrangement, structural Phosphoglucose Isomerase (5.3.1.9)

Question 36

Catalyze the formation of ___ molecules, with the formation of new _____________ usually accompanied by hydrolysis of _____ Example: DNA ______ EC ( __.5.__.1)

Answer 36

Ligases Two, chemical bonds, ATP DNA Ligase (6.5.1.1