Question 1

Which of the following statements is/are true about catalysts?

Accepted Answer

A) They can be used only once. 
B) They participate in the chemical reaction, but are not changed or consumed. 
C) They change the stability of reactants and products. 
D) They change the amount of product formed in a chemical reaction. 
E) all of the above 
A) They can be used only once. 
B) They participate in the chemical reaction, but are not changed or consumed. 
C) They change the stability of reactants and products. 
D) They change the amount of product formed in a chemical reaction. 
E) all of the above

Question 2

"Being in the right place... can be the most powerful factor of all in determining how fast a reaction goes." In terms of reaction rate theory, this statement refers to the ________ for a reaction.

Accepted Answer

A) probability factor 
B) energy factor 
C) resonance effect 
D) inductive effect 
A) probability factor 
B) energy factor 
C) resonance effect 
D) inductive effect

Question 3

How does an acid catalyst increase the rate of reaction?

Accepted Answer

By donatin

Question 4

Give the products of the following reaction.

Accepted Answer

The answer of Give the products of the following reaction....

Question 5

What does the model termed "lock-and-key" stand for?

Accepted Answer

A) The hydrogen bonds in the α-helix fit each other like a key fits a lock. 
B) The amino acids in a peptide chain fit each other like a key fits a lock. 
C) The substrate fits the active site of the enzyme like a key fits a lock. 
D) The nonpolar sites of proteins fit each other like a key fits a lock. 
E) The N-terminal and the C-terminal ends of a protein fit each other like a key fits a lock. 
A) The hydrogen bonds in the α-helix fit each other like a key fits a lock. 
B) The amino acids in a peptide chain fit each other like a key fits a lock. 
C) The substrate fits the active site of the enzyme like a key fits a lock. 
D) The nonpolar sites of proteins fit each other like a key fits a lock. 
E) The N-terminal and the C-terminal ends of a protein fit each other like a key fits a lock.

Question 6

Give the final step for the mechanism for glucose-6-phosphate isomerase.

Accepted Answer

A) In the ring opening reaction, a base catalyst removes a proton from the OH group and an acid catalyst aids in the departure of the leaving group by protonating it. 
B) A base catalyst removes a proton from the a-carbon of the aldehyde. 
C) The enol is converted to a ketone. 
D) The ester group is hydrolyzed. 
E) The conjugate base of the acid catalyst and the conjugate acid of the base catalyst catalyze ring closure. 
A) In the ring opening reaction, a base catalyst removes a proton from the OH group and an acid catalyst aids in the departure of the leaving group by protonating it. 
B) A base catalyst removes a proton from the a-carbon of the aldehyde. 
C) The enol is converted to a ketone. 
D) The ester group is hydrolyzed. 
E) The conjugate base of the acid catalyst and the conjugate acid of the base catalyst catalyze ring closure.

Question 7

How does a metal catalyst increase the rate of reaction?

Accepted Answer

The metal ions coord

Question 8

Which ester below hydrolyzes more readily and why?

Accepted Answer

The presence of the ortho carb

Question 9

Which of the following sets of amino acids is found in all serine proteases?

Accepted Answer

A) arginine, histidine, serine 
B) arginine, aspartate, serine 
C) proline, histidine, serine 
D) aspartate, histidine, serine 
E) aspartate, proline, serine 
A) arginine, histidine, serine 
B) arginine, aspartate, serine 
C) proline, histidine, serine 
D) aspartate, histidine, serine 
E) aspartate, proline, serine

Question 10

Hydrolysis of esters occurs more rapidly in the presence of catalytic imidazole. Explain this phenomenon and provide the structure of the acyl imidazole intermediate which is formed in the catalyzed process.

Accepted Answer

Imidazole is a better nucleophile than w

Question 11

How does a base catalyst increase the rate of reaction?

Accepted Answer

by removin

Question 12

In glycolysis which enzyme catalyzes the cleavage of fructose-1,6-bisphosphate into 2 three-carbon compounds?

Accepted Answer

A) aldolase 
B) glucose-6-phosphate isomerase 
C) fructoprotease 
D) peroxidase 
E) phosphofructokinase 
A) aldolase 
B) glucose-6-phosphate isomerase 
C) fructoprotease 
D) peroxidase 
E) phosphofructokinase

Question 13

Which of the following is an intermediate in the mechanism of hydrolysis of the ester shown below?

Accepted Answer

A)    
B)    
C)    
D)    
E) all of the above 
A)    
B)    
C)    
D)    
E) all of the above

Question 14

In the hydrolysis of methyl trifluoroacetate, give two purposes of the zinc catalyst.
A)increases the rate of the first step by providing a metal-bound hydroxide ion
B)increases the rate of the second step by decreasing the basicity of the leaving group
C)increases the rate of the second step by increasing the basicity of the leaving group
D)increases the rate of the first step by providing a metal-bound water molecule
E)increases the rate of the last step by replacing alkoxide with hydroxide

Accepted Answer

The answer of In the hydrolysis of methyl trifluoroacetate, give...

Question 15

An acid catalyst functions by donating ________ to a substrate.

Accepted Answer

A) a proton 
B) an electron 
C) an electron pair 
D) a nucleophile 
E) a molecule of water 
A) a proton 
B) an electron 
C) an electron pair 
D) a nucleophile 
E) a molecule of water

Question 16

Describe the reaction coordinate diagram for a general-acid-catalyzed reaction.

Accepted Answer

A) one peak 
B) two peaks, second peak is larger 
C) two peaks, second peak is smaller 
D) two peaks, equal size 
E) three peaks, middle peak is larger 
A) one peak 
B) two peaks, second peak is larger 
C) two peaks, second peak is smaller 
D) two peaks, equal size 
E) three peaks, middle peak is larger

Question 17

Which of the following residues are found at the active site of lysozyme?

Accepted Answer

A) His 57, Asp 102 
B) His 57, Asp 52 
C) Glu 35, His 57 
D) Asp 102, Glu 35 
E) Glu 35, Asp 52 
A) His 57, Asp 102 
B) His 57, Asp 52 
C) Glu 35, His 57 
D) Asp 102, Glu 35 
E) Glu 35, Asp 52

Question 18

Which of the following is the best definition of a catalyst?

Accepted Answer

A) It increases the rate of a chemical reaction. 
B) It decreases the rate of a reaction. 
C) It decreases activation energy. 
D) It increases activation energy. 
E) A and C 
A) It increases the rate of a chemical reaction. 
B) It decreases the rate of a reaction. 
C) It decreases activation energy. 
D) It increases activation energy. 
E) A and C

Question 19

Explain what is meant by the induced fit model. Give an example.

Accepted Answer

Binding energy from the substr

Question 20

Which of the following residues acts as a general-base catalyst in the cleavage of the C3-C4 bond in the mechanism of the aldolase-catalyzed reaction?

Accepted Answer

A) methionine 
B) histidine 
C) cysteine 
D) asparagine 
E) lysine 
A) methionine 
B) histidine 
C) cysteine 
D) asparagine 
E) lysine

Exam 23: Catalysis

Which of the following statements is/are true about catalysts?

"Being in the right place... can be the most powerful factor of all in determining how fast a reaction goes." In terms of reaction rate theory, this statement refers to the ________ for a reaction.

How does an acid catalyst increase the rate of reaction?

Give the products of the following reaction.

What does the model termed "lock-and-key" stand for?

Give the final step for the mechanism for glucose-6-phosphate isomerase.

How does a metal catalyst increase the rate of reaction?

Which ester below hydrolyzes more readily and why?

Which of the following sets of amino acids is found in all serine proteases?

Hydrolysis of esters occurs more rapidly in the presence of catalytic imidazole. Explain this phenomenon and provide the structure of the acyl imidazole intermediate which is formed in the catalyzed process.

How does a base catalyst increase the rate of reaction?

In glycolysis which enzyme catalyzes the cleavage of fructose-1,6-bisphosphate into 2 three-carbon compounds?

Which of the following is an intermediate in the mechanism of hydrolysis of the ester shown below?

An acid catalyst functions by donating ________ to a substrate.

Describe the reaction coordinate diagram for a general-acid-catalyzed reaction.

Which of the following residues are found at the active site of lysozyme?

Which of the following is the best definition of a catalyst?

Explain what is meant by the induced fit model. Give an example.

Which of the following residues acts as a general-base catalyst in the cleavage of the C3-C4 bond in the mechanism of the aldolase-catalyzed reaction?

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds

Isomers: the Arrangement of Atoms in Space

Alkenes Thermodynamics and Kinetics

Reactions of Alkenes

Reactions of Alkynes Introduction to Multistep Synthesis

Electron Delocalization, Resonance, and Aromaticity More About Molecular Orbital Theory

Substitution Reactions of Alkyl Halides

Elimination Reactions of Alkyl Halides Competition Between Substitution and Elimination

Reactions of Alcohols, Ethers, Epoxides, and Sulfur-Containing Compounds

Organometallic Compounds

Reactions of Alkanes, Radicals

Mass Spectrometry, Infrared Spectroscopy, and Uvvis Spectroscopy

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Alpha Carbon of Carbonyl Compounds

Reactions of Benzene and Substituted Benzenes

More About Amines Heterocylic Compounds

Carbohydrates

Amino Acids, Peptides, and Proteins

The Organic Mechanisms of the Coenzymes

The Chemistry of Metabolism

Nucleosides, Nucleotides, and Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

Which of the following residues acts as a general-base catalyst in the cleavage of the C₃-C₄ bond in the mechanism of the aldolase-catalyzed reaction?