Question 1

Which of the following statements about enzymatic catalysis is not true?

Accepted Answer

A)  Enzymes are able to provide different solvent environments at the active site. 
B)  Enzymes allow one group to exist in its acidic form while a nearby group can exist in its basic form. 
C)  Solvent pH is unimportant in enzymatic reactions. 
D)  Enzyme activity depends on the reaction mixture pH. 
E)  A pH-rate profile plots enzyme activity versus pH. 
A)  Enzymes are able to provide different solvent environments at the active site. 
B)  Enzymes allow one group to exist in its acidic form while a nearby group can exist in its basic form. 
C)  Solvent pH is unimportant in enzymatic reactions. 
D)  Enzyme activity depends on the reaction mixture pH. 
E)  A pH-rate profile plots enzyme activity versus pH. C

Question 2

Which of the following is not true about nucleophilic catalysis?

Accepted Answer

A)  Nucleophilic catalysts form new covalent bonds with the reactants. 
B)  Nucleophilic catalysis will not involve positively charged intermediates. 
C)  Nucleophilic catalysis is also called covalent catalysis. 
D)  A nucleophilic catalyst increases the reaction rate by completely changing the mechanism of the reaction. 
E)  Nucleophilic catalysts are often good leaving groups. 
A)  Nucleophilic catalysts form new covalent bonds with the reactants. 
B)  Nucleophilic catalysis will not involve positively charged intermediates. 
C)  Nucleophilic catalysis is also called covalent catalysis. 
D)  A nucleophilic catalyst increases the reaction rate by completely changing the mechanism of the reaction. 
E)  Nucleophilic catalysts are often good leaving groups. B

Question 3

Which of the following factors is important in determining the rate of intramolecular reactions?

Accepted Answer

A)  number of collisions per unit time 
B)  fraction of molecules with sufficient energy 
C)  fraction of molecules with proper orientation 
D)  favorable conformation for reaction 
E)  all of the above 
A)  number of collisions per unit time 
B)  fraction of molecules with sufficient energy 
C)  fraction of molecules with proper orientation 
D)  favorable conformation for reaction 
E)  all of the above E

Question 4

Which factor contributes to the catalytic activity of enzymes?

Accepted Answer

A)  Reacting groups are brought together at the active site in the proper orientation. 
B)  Amino acid side chains serve as catalysts. 
C)  Metal ions in the active site act as catalysts. 
D)  Amino acid side chains stabilize transition states and intermediates. 
E)  all of the above 
A)  Reacting groups are brought together at the active site in the proper orientation. 
B)  Amino acid side chains serve as catalysts. 
C)  Metal ions in the active site act as catalysts. 
D)  Amino acid side chains stabilize transition states and intermediates. 
E)  all of the above

Question 5

Which of the following statements about trypsin, chymotrypsin, and elastase are true?

Accepted Answer

A)  They are serine proteases. 
B)  They are endopeptidases. 
C)  Serine is part of both tetrahedral intermediates in the enzymatic mechanism. 
D)  Acid, base, and nucleophilic catalysis are utilized in the overall mechanism for these proteases. 
E)  All of the above are true. 
A)  They are serine proteases. 
B)  They are endopeptidases. 
C)  Serine is part of both tetrahedral intermediates in the enzymatic mechanism. 
D)  Acid, base, and nucleophilic catalysis are utilized in the overall mechanism for these proteases. 
E)  All of the above are true.

Question 6

What type of intramolecular catalysis is occurring in the following reaction?

Accepted Answer

A)  acid 
B)  base 
C)  nucleophilic 
D)  metal ion 
E)  none of the above 
A)  acid 
B)  base 
C)  nucleophilic 
D)  metal ion 
E)  none of the above

Question 7

Which of the following statements about enzyme-catalyzed isomerization of glucose-6-phosphate to fructose-6-phosphate is not true?

Accepted Answer

A)  The mechanism is totally different from the laboratory version of the enediol rearrangement. 
B)  The first step is acid- and base-catalyzed ring opening. 
C)  The second step is a base-catalyzed enediol rearrangement. 
D)  The third step is acid- and base-catalyzed conversion of the enediol to a ketone. 
E)  The fourth step is acid- and base-catalyzed ring closure. 
A)  The mechanism is totally different from the laboratory version of the enediol rearrangement. 
B)  The first step is acid- and base-catalyzed ring opening. 
C)  The second step is a base-catalyzed enediol rearrangement. 
D)  The third step is acid- and base-catalyzed conversion of the enediol to a ketone. 
E)  The fourth step is acid- and base-catalyzed ring closure.

Question 8

Which of the following is an intermediate in the acid-catalyzed hydrolysis of an ester?

Accepted Answer

A)    
B)    
C)    
D)  Intermediates B and C 
E)  Intermediates A, B, and C 
A)    
B)    
C)    
D)  Intermediates B and C 
E)  Intermediates A, B, and C

Question 9

Which of the following is not true about metal-ion catalysis?

Accepted Answer

A)  It can increase the rate of a reaction by removing a proton from the reactant. 
B)  It can make a reaction center more susceptible to receiving electrons. 
C)  It can make a leaving group a weaker base and therefore a better leaving group. 
D)  It can increase the rate of a hydrolysis reaction by increasing the nucleophilicity of water. 
A)  It can increase the rate of a reaction by removing a proton from the reactant. 
B)  It can make a reaction center more susceptible to receiving electrons. 
C)  It can make a leaving group a weaker base and therefore a better leaving group. 
D)  It can increase the rate of a hydrolysis reaction by increasing the nucleophilicity of water.

Question 10

Which of the following are common types of catalysts used in organic reactions?

Accepted Answer

A)  acid catalysts 
B)  base catalysts 
C)  nucleophilic catalysts 
D)  metal ion catalysts 
E)  all of the above 
A)  acid catalysts 
B)  base catalysts 
C)  nucleophilic catalysts 
D)  metal ion catalysts 
E)  all of the above

Which of the following statements about enzymatic catalysis is not true?

Which of the following is not true about nucleophilic catalysis?

Which of the following factors is important in determining the rate of intramolecular reactions?

Which factor contributes to the catalytic activity of enzymes?

Which of the following statements about trypsin, chymotrypsin, and elastase are true?

What type of intramolecular catalysis is occurring in the following reaction?

Which of the following statements about enzyme-catalyzed isomerization of glucose-6-phosphate to fructose-6-phosphate is not true?

Which of the following is an intermediate in the acid-catalyzed hydrolysis of an ester?

Which of the following is not true about metal-ion catalysis?

Which of the following are common types of catalysts used in organic reactions?

Remembering General Chemistry Electronic Structure and Bonding

Acids and Bases Central to Understanding Organic Chemistry

An Introduction to Organic Compounds Nomenclature, Physical Properties, and Structure

Isomers the Arrangement of Atoms in Space

Alkenes Structure, Nomenclature, and an Introduction to Reactivity Thermodynamics and Kinetics

The Reactions of Alkenes the Stereochemistry of Addition Reactions

The Reactions of Alkynes an Introduction Tomultistep Synthesis

Delocalized Electrons Their Eff

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, Ethers,epoxides, Amines, and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Mass Spectrometry Infrared Spectroscopy Uv Vis Spectroscopy

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones More Reactions of Carboxylic Acid Derivatives

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines Reactions of Heterocyclic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids, Peptides, and Proteins

The Organic Chemistry of the Coenzymes,compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

Exam 22: Catalysis in Organic Reactions and in Enzymatic Reactions

Which of the following statements about enzymatic catalysis is not true?

Which of the following is not true about nucleophilic catalysis?

Which of the following factors is important in determining the rate of intramolecular reactions?

Which factor contributes to the catalytic activity of enzymes?

Which of the following statements about trypsin, chymotrypsin, and elastase are true?

What type of intramolecular catalysis is occurring in the following reaction?

Which of the following statements about enzyme-catalyzed isomerization of glucose-6-phosphate to fructose-6-phosphate is not true?

Which of the following is an intermediate in the acid-catalyzed hydrolysis of an ester?

Which of the following is not true about metal-ion catalysis?

Which of the following are common types of catalysts used in organic reactions?

Remembering General Chemistry Electronic Structure and Bonding

Acids and Bases Central to Understanding Organic Chemistry

An Introduction to Organic Compounds Nomenclature, Physical Properties, and Structure

Isomers the Arrangement of Atoms in Space

Alkenes Structure, Nomenclature, and an Introduction to Reactivity Thermodynamics and Kinetics

The Reactions of Alkenes the Stereochemistry of Addition Reactions

The Reactions of Alkynes an Introduction Tomultistep Synthesis

Delocalized Electrons Their Eff

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, Ethers,epoxides, Amines, and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Mass Spectrometry Infrared Spectroscopy Uv Vis Spectroscopy

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones More Reactions of Carboxylic Acid Derivatives

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines Reactions of Heterocyclic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids, Peptides, and Proteins

The Organic Chemistry of the Coenzymes,compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters