Question 1

What effect is seen on a Lineweaver-Burk graph when a competitive inhibitor is added?

Accepted Answer

A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed. 
A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed.

Question 2

The initial rate of an enzymatic reaction is usually determined in order to assure that

Accepted Answer

A)  the enzyme is active 
B)  there is no reverse reaction of product to the enzyme-substrate complex 
C)  the substrate is not used up 
D)  the experiment can be completed quickly 
A)  the enzyme is active 
B)  there is no reverse reaction of product to the enzyme-substrate complex 
C)  the substrate is not used up 
D)  the experiment can be completed quickly

Question 3

If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the x-intercept, it is this type of inhibition:

Accepted Answer

A)  Competitive. 
B)  Non-competitive. 
C)  Mixed Inhibition (uncompetitive inhibition). 
D)  You cannot tell from the data given. 
E)  More than one answer is correct. 
A)  Competitive. 
B)  Non-competitive. 
C)  Mixed Inhibition (uncompetitive inhibition). 
D)  You cannot tell from the data given. 
E)  More than one answer is correct.

Question 4

The order of a reaction can be determined from the balanced equation for the reaction.

Accepted Answer

A) True 
 B)False

Question 5

Exhibit 6A This is a reaction going on in your muscle cells right this very minute:   The enzyme triose phosphate isomerase catalyzes this reaction in the forward direction as part of the glycolytic pathway. It follows simple Michaelis-Menten kinetics:  
Typical cellular concentrations: triose phosphate isomerase = 0.1 nM
Dihydroxyacetone phosphate = 5 µM glyceraldehyde-3-phosphate = 2 µM
Refer to Exhibit 6A. What is the Vmax of the enzyme?

Accepted Answer

A)  90 nM\s 
B)  4500 µM\s 
C)  200 µM\s 
D)  0.5 M\s 
A)  90 nM\s 
B)  4500 µM\s 
C)  200 µM\s 
D)  0.5 M\s

Question 6

In the reaction catalyzed by aspartate transcarbamoylase, a graph in which the rate is plotted against the concentration of substrate

Accepted Answer

A)  is sigmoidal, characteristic of an allosteric enzyme 
B)  shows that noncooperative kinetics are observed 
C)  shows that the reaction is zero order 
D)  is hyperbolic, characteristic of a nonallosteric enzyme 
A)  is sigmoidal, characteristic of an allosteric enzyme 
B)  shows that noncooperative kinetics are observed 
C)  shows that the reaction is zero order 
D)  is hyperbolic, characteristic of a nonallosteric enzyme

Question 7

A rate constant is

Accepted Answer

A)  the rate of a reaction at standard temperature and pressure. 
B)  the rate of a reaction at equilibrium. 
C)  a proportionality constant relating the rate of a reaction to the concentration(s) of the reactant(s). 
D)  a kind of transition state. 
A)  the rate of a reaction at standard temperature and pressure. 
B)  the rate of a reaction at equilibrium. 
C)  a proportionality constant relating the rate of a reaction to the concentration(s) of the reactant(s). 
D)  a kind of transition state.

Question 8

Pure noncompetitive inhibition is a limiting case of

Accepted Answer

A)  Competitive inhibition 
B)  Uncompetitive inhibition 
C)  Irreversible inhibition 
D)  Mixed inhibition 
E)  None of these is true 
A)  Competitive inhibition 
B)  Uncompetitive inhibition 
C)  Irreversible inhibition 
D)  Mixed inhibition 
E)  None of these is true

Question 9

What effect is seen on a Lineweaver-Burk graph when a non-competitive inhibitor is added?

Accepted Answer

A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed. 
A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed.

Question 10

If the y-intercept of a Lineweaver-Burk plot = 1.91 (sec\millimole) and the slope = 75.3 L\sec, KM equals:

Accepted Answer

A)  0.0254 millimolar (mM). 
B)  0.523 millimolar (mM). 
C)  5.23 millimolar (mM). 
D)  39.4 millimolar (mM). 
E)  75.3 millimolar (mM). 
A)  0.0254 millimolar (mM). 
B)  0.523 millimolar (mM). 
C)  5.23 millimolar (mM). 
D)  39.4 millimolar (mM). 
E)  75.3 millimolar (mM).

Question 11

The Michaelis constant is

Accepted Answer

A)  related to the molecular weight of the enzyme 
B)  a measure of the resistance of the enzyme to denaturation 
C)  a reflection of the percentage of polar amino acids in the enzyme 
D)  a rough measure of the affinity of the enzyme for the substrate 
A)  related to the molecular weight of the enzyme 
B)  a measure of the resistance of the enzyme to denaturation 
C)  a reflection of the percentage of polar amino acids in the enzyme 
D)  a rough measure of the affinity of the enzyme for the substrate

Question 12

Given the rate law, rate = k[A][B], the overall reaction order is

Accepted Answer

A)  zero 
B)  one 
C)  two 
D)  cannot be determined 
A)  zero 
B)  one 
C)  two 
D)  cannot be determined

Question 13

If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the y-intercept, it is this type of inhibition:

Accepted Answer

A)  Competitive. 
B)  Non-competitive. 
C)  Mixed Inhibition (uncompetitive inhibition). 
D)  You cannot tell from the data given. 
E)  More than one answer is correct. 
A)  Competitive. 
B)  Non-competitive. 
C)  Mixed Inhibition (uncompetitive inhibition). 
D)  You cannot tell from the data given. 
E)  More than one answer is correct.

Question 14

What effect does a catalyst have on the Δ G ° of a reaction?

Accepted Answer

A)  A catalyst lowers the Δ G ° . 
B)  A catalyst raises the Δ G ° . 
C)  A catalyst has no effect on the Δ G ° . 
D)  It depend on the specific catalyst. 
A)  A catalyst lowers the Δ G ° . 
B)  A catalyst raises the Δ G ° . 
C)  A catalyst has no effect on the Δ G ° . 
D)  It depend on the specific catalyst.

Question 15

First order kinetics means

Accepted Answer

A)  The rate of a reaction is independent of the amount of reactant measured. 
B)  The rate of the reaction varies directly with the amount of reactant measured. 
C)  The rate of the reaction varies with the square of the amount of the reactant measured. 
D)  More information is needed to answer this question. 
E)  None of these is correct. 
A)  The rate of a reaction is independent of the amount of reactant measured. 
B)  The rate of the reaction varies directly with the amount of reactant measured. 
C)  The rate of the reaction varies with the square of the amount of the reactant measured. 
D)  More information is needed to answer this question. 
E)  None of these is correct.

Question 16

The steady state of an enzyme reaction is the following:

Accepted Answer

A)  The rate observed just after mixing the enzyme and substrate. 
B)  The rate observed and Vmax. 
C)  The rate of product formation. 
D)  The state which exists when E-S complex is forming as fast as it is breaking down. 
E)  The state which exists when substrate concentration equals KM. 
A)  The rate observed just after mixing the enzyme and substrate. 
B)  The rate observed and Vmax. 
C)  The rate of product formation. 
D)  The state which exists when E-S complex is forming as fast as it is breaking down. 
E)  The state which exists when substrate concentration equals KM.

Question 17

What effect is seen on a Lineweaver-Burk graph when a mixed-type inhibitor is added?

Accepted Answer

A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed. 
A)  The y-intercept is changed, but not change the slope of the line. 
B)  The slope of the line is changed, but not the y-intercept. 
C)  Both the y-intercept and the slope of the line are changed. 
D)  Neither the y-intercept not the slope of the line is changed.

Question 18

When an enzyme is saturated with substrates,

Accepted Answer

A)  it will display zero-order kinetics. 
B)  it will display first-order kinetics. 
C)  it will display second-order kinetics. 
D)  it will denature and cease to function. 
A)  it will display zero-order kinetics. 
B)  it will display first-order kinetics. 
C)  it will display second-order kinetics. 
D)  it will denature and cease to function.

Question 19

Competitive inhibitors have this effect:

Accepted Answer

A)  Modifying the KM value. 
B)  Changing the value for Vmax. 
C)  Interfering with substrate binding. 
D)  This type of inhibitor both changes the KM and interferes with substrate binding. 
E)  All of these are correct. 
A)  Modifying the KM value. 
B)  Changing the value for Vmax. 
C)  Interfering with substrate binding. 
D)  This type of inhibitor both changes the KM and interferes with substrate binding. 
E)  All of these are correct.

Question 20

The substrate-enzyme (E-S) complex

Accepted Answer

A)  always proceeds to form the products rapidly. 
B)  always breaks down to form free enzyme and substrate. 
C)  always breaks down to form free enzyme and product. 
D)  may break down to form free enzyme and substrate, or free enzyme and product. 
A)  always proceeds to form the products rapidly. 
B)  always breaks down to form free enzyme and substrate. 
C)  always breaks down to form free enzyme and product. 
D)  may break down to form free enzyme and substrate, or free enzyme and product.

Exam 6: The Behavior of Proteins Enzymes

What effect is seen on a Lineweaver-Burk graph when a competitive inhibitor is added?

The initial rate of an enzymatic reaction is usually determined in order to assure that

If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the x-intercept, it is this type of inhibition:

The order of a reaction can be determined from the balanced equation for the reaction.

In the reaction catalyzed by aspartate transcarbamoylase, a graph in which the rate is plotted against the concentration of substrate

A rate constant is

Pure noncompetitive inhibition is a limiting case of

What effect is seen on a Lineweaver-Burk graph when a non-competitive inhibitor is added?

If the y-intercept of a Lineweaver-Burk plot = 1.91 (sec\millimole) and the slope = 75.3 L\sec, KM equals:

The Michaelis constant is

Given the rate law, rate = k[A][B], the overall reaction order is

If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the y-intercept, it is this type of inhibition:

What effect does a catalyst have on the Δ G ° of a reaction?

First order kinetics means

The steady state of an enzyme reaction is the following:

What effect is seen on a Lineweaver-Burk graph when a mixed-type inhibitor is added?

When an enzyme is saturated with substrates,

Competitive inhibitors have this effect:

The substrate-enzyme (E-S) complex

Biochemistry and the Organization of Cells

Water the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins Enzymes Mechanisms and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids How Structure Conveys Information

Biosynthesis of Nucleic Acids Replication

Transcription of the Genetic Code the Biosynthesis of Rna

Protein Synthesis Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses Cancer and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism Cellular Signaling

Filters

If the y-intercept of a Lineweaver-Burk plot = 1.91 (sec\millimole) and the slope = 75.3 L\sec, K_M equals: