Question 1

Enzymes which have induced fit to the substrate are generally more effective than those in an active form initially.

Accepted Answer

A) True 
 B)False

Question 2

A reaction that occurs with every collision between reactant molecules is called a/an .

Accepted Answer

A)  saturation point 
B)  diffusion-controlled reaction 
C)  rate-determining step 
D)  first order reaction 
A)  saturation point 
B)  diffusion-controlled reaction 
C)  rate-determining step 
D)  first order reaction

Question 3

Trypsin as well as chymotrypsin can activate chymotrypsinogen to chymotrypsin.

Accepted Answer

A) True 
 B)False

Question 4

In the following chemical reaction which species is the reducing agent? CH4 + 2 O2 → CO2 + 2 H2O

Accepted Answer

A)  CH4 
B)  O2 
C)  CO2 
D)  H2O 
E)  none of the above, this is not an oxidation-reduction reaction 
A)  CH4 
B)  O2 
C)  CO2 
D)  H2O 
E)  none of the above, this is not an oxidation-reduction reaction

Question 5

The proximity effect of speeding an enzyme-catalyzed reaction is explained by .

Accepted Answer

A)  a large loss of entropy when reactive groups are brought close to each other 
B)  a large gain in entropy due to binding of the substrate 
C)  a conversion of a reaction from endergonic to exergonic 
D)  increasing the flexibility of the substrate by increasing its degrees of freedom of rotation 
A)  a large loss of entropy when reactive groups are brought close to each other 
B)  a large gain in entropy due to binding of the substrate 
C)  a conversion of a reaction from endergonic to exergonic 
D)  increasing the flexibility of the substrate by increasing its degrees of freedom of rotation

Question 6

The roles of amino acid residues at the active site of enzymes can be determined by removing certain residues using the technique of

Accepted Answer

A)  specific hydrolysis. 
B)  covalent binding. 
C)  acylation of specific residues. 
D)  site mutagenesis. 
E)  All of the above 
A)  specific hydrolysis. 
B)  covalent binding. 
C)  acylation of specific residues. 
D)  site mutagenesis. 
E)  All of the above

Question 7

Most Km values of enzymes for their substrates are on the order of M.

Accepted Answer

A)  10-2  
B)  10-3  
C)  10-4  
D)  10-5  
E)  10-6 
A)  10-2  
B)  10-3  
C)  10-4  
D)  10-5  
E)  10-6

Question 8

Aspartate and lysine are in the active site of an enzyme. They are both known to participate directly in catalysis. The pKaʹs of the residues are found to be 3.2 and 9.6, respectively for aspartate and lysine. The optimum pH for the enzyme is 6.4. Which forms of these two residues will predominate when the enzyme is most active?

Accepted Answer

A)  aspartate is protonated; lysine is deprotonated 
B)  both residues are protonated 
C)  aspartate is deprotonated; lysine is protonated 
D)  both residues are deprotonated 
A)  aspartate is protonated; lysine is deprotonated 
B)  both residues are protonated 
C)  aspartate is deprotonated; lysine is protonated 
D)  both residues are deprotonated

Question 9

Transition state analogs should

Accepted Answer

A)  stabilize transition states. 
B)  have a dissociation constant of 10-13 M or less. 
C)  bind very tightly to the enzyme. 
D)  A and C 
E)  B and C 
A)  stabilize transition states. 
B)  have a dissociation constant of 10-13 M or less. 
C)  bind very tightly to the enzyme. 
D)  A and C 
E)  B and C

Question 10

Nucleophiles are often anions or have unshared electrons.

Accepted Answer

A) True 
 B)False

Question 11

Which graph might you expect for the pH profile of an enzymeʹs activity if the only ionizable residue in the active site is aspartate?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
A)  I 
B)  II 
C)  III 
D)  IV

Question 12

Which represents a hydride ion?

Accepted Answer

A)  H2-  
B)  H-  
C)  H+  
D)  H3O+ 
A)  H2-  
B)  H-  
C)  H+  
D)  H3O+

Question 13

X-ray crystallographic examination of the active site of arginine kinase was possible because

Accepted Answer

A)  it could be crystallized in the different structural forms. 
B)  nitrate could be substituted for phosphate in the reaction. 
C)  it was readily purified unlike most other enzymes). 
D)  MgADP was involved in the reaction. 
E)  All of the above 
A)  it could be crystallized in the different structural forms. 
B)  nitrate could be substituted for phosphate in the reaction. 
C)  it was readily purified unlike most other enzymes). 
D)  MgADP was involved in the reaction. 
E)  All of the above

Question 14

Weak substrate binding is an important feature to help describe enzyme catalysis.

Accepted Answer

A) True 
 B)False

Question 15

An update of Fischerʹs lock-and-key theory of enzyme specificity view the as the lock and as the key.

Accepted Answer

A)  enzyme; substrate 
B)  substrate; enzyme 
C)  enzyme; transition state 
D)  transition state; enzyme 
E)  substrate; transition state 
A)  enzyme; substrate 
B)  substrate; enzyme 
C)  enzyme; transition state 
D)  transition state; enzyme 
E)  substrate; transition state

Enzymes which have induced fit to the substrate are generally more effective than those in an active form initially.

A reaction that occurs with every collision between reactant molecules is called a/an .

Trypsin as well as chymotrypsin can activate chymotrypsinogen to chymotrypsin.

In the following chemical reaction which species is the reducing agent? CH₄+ 2 O₂→ CO₂+ 2 H₂O

The proximity effect of speeding an enzyme-catalyzed reaction is explained by .

The roles of amino acid residues at the active site of enzymes can be determined by removing certain residues using the technique of

Most K_mvalues of enzymes for their substrates are on the order of M.

Transition state analogs should

Nucleophiles are often anions or have unshared electrons.

Which graph might you expect for the pH profile of an enzymeʹs activity if the only ionizable residue in the active site is aspartate?

Which represents a hydride ion?

X-ray crystallographic examination of the active site of arginine kinase was possible because

Weak substrate binding is an important feature to help describe enzyme catalysis.

An update of Fischerʹs lock-and-key theory of enzyme specificity view the as the lock and as the key.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

Filters

Exam 6: Mechanisms of Enzymes

Enzymes which have induced fit to the substrate are generally more effective than those in an active form initially.

A reaction that occurs with every collision between reactant molecules is called a/an .

Trypsin as well as chymotrypsin can activate chymotrypsinogen to chymotrypsin.

In the following chemical reaction which species is the reducing agent? CH4 + 2 O2 → CO2 + 2 H2O

The proximity effect of speeding an enzyme-catalyzed reaction is explained by .

The roles of amino acid residues at the active site of enzymes can be determined by removing certain residues using the technique of

Most Km values of enzymes for their substrates are on the order of M.

Transition state analogs should

Nucleophiles are often anions or have unshared electrons.

Which graph might you expect for the pH profile of an enzymeʹs activity if the only ionizable residue in the active site is aspartate?

Which represents a hydride ion?

X-ray crystallographic examination of the active site of arginine kinase was possible because

Weak substrate binding is an important feature to help describe enzyme catalysis.

An update of Fischerʹs lock-and-key theory of enzyme specificity view the as the lock and as the key.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

Filters

In the following chemical reaction which species is the reducing agent? CH₄+ 2 O₂→ CO₂+ 2 H₂O

Most K_mvalues of enzymes for their substrates are on the order of M.