Question 1

At substrate concentrations much lower than the enzyme concentration,

Accepted Answer

A) the rate of reaction is expected to be inversely proportional to substrate concentration. 
B) the rate of reaction is expected to be directly proportional to substrate concentration. 
C) first order enzyme kinetics are not observed. 
D) the KM is lower. 
E) the rate of reaction is independent of substrate concentration. 
A) the rate of reaction is expected to be inversely proportional to substrate concentration. 
B) the rate of reaction is expected to be directly proportional to substrate concentration. 
C) first order enzyme kinetics are not observed. 
D) the KM is lower. 
E) the rate of reaction is independent of substrate concentration. B

Question 2

Matching
-In uncompetitive inhibition, the inhibitor binds only to the ______.

Accepted Answer

A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] 
A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] F

Question 3

Matching
-A common type of covalent modification of regulatory enzymes involves ______ of serine residues.

Accepted Answer

A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] 
A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] L

Question 4

Matching
-The E+S$\rarr$ E+P reaction is ______.

Accepted Answer

A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] 
A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B]

Question 5

A new drug has been discovered which inhibits the reaction catalyzed by enzyme A.Based on the information shown below, what is this drug?

Accepted Answer

A) competitive inhibitor 
B) uncompetitive inhibitor 
C) mixed inhibitor 
D) allosteric activator 
E) More information is required to answer the question. 
A) competitive inhibitor 
B) uncompetitive inhibitor 
C) mixed inhibitor 
D) allosteric activator 
E) More information is required to answer the question.

Question 6

Matching
-In ______, the inhibitor binds to a site involved in both substrate binding and catalysis.

Accepted Answer

A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B] 
A) isozymes 
B) [A] 
C) the rate constant 
D) Ping Pong 
E) bimolecular
F)ES complex
G)random ordered
H)competitive inhibition
I)unimolecular
J)[A]²
K)Competitive inhibition
L)phosphorylation
M)small KS
N)large KS
O)uncompetitive inhibition
P)[B]

Question 7

Based on the figures below, which of the following expressions would be correct?

Accepted Answer

A) Vmax = 1/B 
B) C = 1/ Vmax 
C) D= Vmax 
D) D = 1/ Vmax 
E) A = 1/ Vmax 
A) Vmax = 1/B 
B) C = 1/ Vmax 
C) D= Vmax 
D) D = 1/ Vmax 
E) A = 1/ Vmax

Question 8

The catalytic efficiency of an enzyme can never exceed

Accepted Answer

A) k2. 
B) k1. 
C) k-1. 
D) k-1 + k2. 
E) (k-1 + k2)/k1. 
A) k2. 
B) k1. 
C) k-1. 
D) k-1 + k2. 
E) (k-1 + k2)/k1.

Question 9

In order for an enzymatic reaction obeying the Michaelis-Menten equation to reach 3/4 of its maximum velocity,

Accepted Answer

A) [S] would need to be equal to KM 
B) [S] would need to be ½ KM 
C) [S] would need to be 3KM 
D) [S] would need to be ¾ KM 
E) not enough information is given to make this calculation 
A) [S] would need to be equal to KM 
B) [S] would need to be ½ KM 
C) [S] would need to be 3KM 
D) [S] would need to be ¾ KM 
E) not enough information is given to make this calculation

Question 10

Parallel lines on a Lineweaver-Burk plot indicate
I.an increase in KM.
II.decrease in KM.
III.decrease in Vmax.
IV.uncompetitive inhibition.

Accepted Answer

A) I, IV 
B) II, III, IV 
C) I or II, III 
D) I or III, II 
E) I, III, IV 
A) I, IV 
B) II, III, IV 
C) I or II, III 
D) I or III, II 
E) I, III, IV

Question 11

The KM can be considered to be the same as the dissociation constant KS for E + S binding if

Accepted Answer

A) the concentration of [ES] is unchanged. 
B) ES $\rightarrow$ E + P is fast compared to ES $\rightarrow$ E + S. 
C) k1 >> k2 
D) k2 -1. 
E) this statement cannot be completed because KM can never approximate KS. 
A) the concentration of [ES] is unchanged. 
B) ES $\rightarrow$ E + P is fast compared to ES $\rightarrow$ E + S. 
C) k1 >> k2 
D) k2 -1. 
E) this statement cannot be completed because KM can never approximate KS.

Question 12

Allosteric activators

Accepted Answer

A) bind via covalent attachment. 
B) stabilize conformations with higher Ks. 
C) stabilize conformations with higher substrate affinity. 
D) all of the above 
E) none of the above. 
A) bind via covalent attachment. 
B) stabilize conformations with higher Ks. 
C) stabilize conformations with higher substrate affinity. 
D) all of the above 
E) none of the above.

Question 13

In the plot below, can the KM be determined? If so, what is its value?

Accepted Answer

A) Yes, it is 30 mM. 
B) Yes, it is 30 mM/sec. 
C) Yes, it is 60 mM/sec 
D) Yes, it is 60 mM 
E) No this data does not follow Michaelis-Menten kinetics 
A) Yes, it is 30 mM. 
B) Yes, it is 30 mM/sec. 
C) Yes, it is 60 mM/sec 
D) Yes, it is 60 mM 
E) No this data does not follow Michaelis-Menten kinetics

Question 14

The following data were collected under conditions indicated in the graph below during the time period of 0-5 seconds.Upon plotting the Lineweaver-Burk plot, the information given in the table below was determined.Based on this available information which of the following is FALSE?

Accepted Answer

A) The Vmax equals 200 M/s 
B) The Ks equals 500 M 
C) The kapp equals 200 per second 
D) The data was collected prior to reaching steady state. 
E) The kcat  cannot be determined for this information. 
A) The Vmax equals 200 M/s 
B) The Ks equals 500 M 
C) The kapp equals 200 per second 
D) The data was collected prior to reaching steady state. 
E) The kcat  cannot be determined for this information.

Question 15

Find the initial velocity for an enzymatic reaction when Vmax = 6.5 × 10-5 mol•sec-1, [S] = 3.0 × 10-3 M, KM = 4.5 × 10-3 M and the enzyme concentration at time zero is 1.5 × 10-2 $\mu$M.

Accepted Answer

A) 3.9 × 10-5 mol•sec-1 
B) 2.6 × 10-5 mol•sec-1 
C) 1.4 × 10-2 mol•sec-1 
D) 8.7 × 10-3 mol•sec-1 
E) Not enough information is given to make this calculation. 
A) 3.9 × 10-5 mol•sec-1 
B) 2.6 × 10-5 mol•sec-1 
C) 1.4 × 10-2 mol•sec-1 
D) 8.7 × 10-3 mol•sec-1 
E) Not enough information is given to make this calculation.

Question 16

Compounds that function as "mixed inhibitors"
I.interfere with substrate binding to the enzyme.
II.bind to the enzyme reversibly.
III.can bind to the enzyme/substrate complex.

Accepted Answer

A) I 
B) II 
C) III 
D) II, III 
E) I, II, III 
A) I 
B) II 
C) III 
D) II, III 
E) I, II, III

Question 17

Reaction that is first order with respect to A and B

Accepted Answer

A) is dependent on the concentration of A and B. 
B) is dependent on the concentration of A. 
C) has smaller rate constants than first-order reactions regardless of reactant concentration. 
D) is independent of reactant concentration. 
E) is always faster than first-order reactions due to loss of concentration dependence. 
A) is dependent on the concentration of A and B. 
B) is dependent on the concentration of A. 
C) has smaller rate constants than first-order reactions regardless of reactant concentration. 
D) is independent of reactant concentration. 
E) is always faster than first-order reactions due to loss of concentration dependence.

Question 18

Protein kinases are involved in

Accepted Answer

A) the digestion of drugs to potentially toxic byproducts. 
B) the degradation of enzymes to the component amino acids. 
C) the phosphorylation of a wide variety of proteins. 
D) the metabolism of drugs to water soluble, excretable compounds. 
E) all of the above 
A) the digestion of drugs to potentially toxic byproducts. 
B) the degradation of enzymes to the component amino acids. 
C) the phosphorylation of a wide variety of proteins. 
D) the metabolism of drugs to water soluble, excretable compounds. 
E) all of the above

Question 19

An extremely efficient enzyme called "efficase" catalyzes the conversion of "A" to "B." A researcher decides to mutate the enzyme in order to try to improve its performance.Following active site mutations, a significant reduction in the value of KM and Vmax was observed.Which of the following may have occurred?

Accepted Answer

A) The affinity of the enzyme for the substrate was increased to a point which did not favor propagation (continuation)of the reaction. 
B) The decrease in Vmax was not related to the decrease in KM. 
C) If the reaction was first-order, the change in KM cannot have affected Vmax. 
D) The stability of E+S (E+A as written above)was increased, thereby increasing the KM. 
E) The reverse reaction (breakdown of EA to E+
A) was favored, slowing the Vmax. 
A) The affinity of the enzyme for the substrate was increased to a point which did not favor propagation (continuation)of the reaction. 
B) The decrease in Vmax was not related to the decrease in KM. 
C) If the reaction was first-order, the change in KM cannot have affected Vmax. 
D) The stability of E+S (E+A as written above)was increased, thereby increasing the KM. 
E) The reverse reaction (breakdown of EA to E+
A) was favored, slowing the Vmax.

Question 20

For a reaction A + B $\rightarrow$ C, if the concentration of B is much larger than A so that [B] remains constant during the reaction while [A] is varied, the kinetics will be

Accepted Answer

A) sigmoidal. 
B) pseudo-first-order. 
C) unimolecular. 
D) zero-order. 
E) hyperbolic. 
A) sigmoidal. 
B) pseudo-first-order. 
C) unimolecular. 
D) zero-order. 
E) hyperbolic.

Exam 12: Enzyme Kinetics, Inhibition and Control

At substrate concentrations much lower than the enzyme concentration,

Matching -In uncompetitive inhibition, the inhibitor binds only to the ______.

Matching -A common type of covalent modification of regulatory enzymes involves ______ of serine residues.

Matching -The E+S →\rarr→ E+P reaction is ______.

A new drug has been discovered which inhibits the reaction catalyzed by enzyme A.Based on the information shown below, what is this drug?

Matching -In ______, the inhibitor binds to a site involved in both substrate binding and catalysis.

Based on the figures below, which of the following expressions would be correct?

The catalytic efficiency of an enzyme can never exceed

In order for an enzymatic reaction obeying the Michaelis-Menten equation to reach 3/4 of its maximum velocity,

Parallel lines on a Lineweaver-Burk plot indicate I.an increase in KM. II.decrease in KM. III.decrease in Vmax. IV.uncompetitive inhibition.

The KM can be considered to be the same as the dissociation constant KS for E + S binding if

Allosteric activators

In the plot below, can the KM be determined? If so, what is its value?

The following data were collected under conditions indicated in the graph below during the time period of 0-5 seconds.Upon plotting the Lineweaver-Burk plot, the information given in the table below was determined.Based on this available information which of the following is FALSE?

Find the initial velocity for an enzymatic reaction when Vmax = 6.5 × 10-5 mol•sec-1, [S] = 3.0 × 10-3 M, KM = 4.5 × 10-3 M and the enzyme concentration at time zero is 1.5 × 10-2 μ\muμ M.

Compounds that function as "mixed inhibitors" I.interfere with substrate binding to the enzyme. II.bind to the enzyme reversibly. III.can bind to the enzyme/substrate complex.

Reaction that is first order with respect to A and B

Protein kinases are involved in

For a reaction A + B →\rightarrow→ C, if the concentration of B is much larger than A so that [B] remains constant during the reaction while [A] is varied, the kinetics will be

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

Filters

Matching -The E+S $\rarr$ E+P reaction is ______.

Parallel lines on a Lineweaver-Burk plot indicate I.an increase in K_M. II.decrease in K_M. III.decrease in V_max. IV.uncompetitive inhibition.

The K_M can be considered to be the same as the dissociation constant K_S for E + S binding if

In the plot below, can the K_M be determined? If so, what is its value?

Find the initial velocity for an enzymatic reaction when V_max = 6.5 × 10^-5 mol•sec^-1, [S] = 3.0 × 10^-3 M, K_M = 4.5 × 10^-3 M and the enzyme concentration at time zero is 1.5 × 10^-2 $\mu$ M.

For a reaction A + B $\rightarrow$ C, if the concentration of B is much larger than A so that [B] remains constant during the reaction while [A] is varied, the kinetics will be