Question 1

The following represents a transition-state in a certain reaction.   Which of the following would be the best transition-state analog?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)    A

Question 2

Which of following is true of urease?

Accepted Answer

A)  It catalyzes the degradation of uracil. 
B)  It catalyzes the synthesis of urea. 
C)  It catalyzes the hydrolysis of urea. 
D)  It catalyzes the hydrolysis of all amines. 
A)  It catalyzes the degradation of uracil. 
B)  It catalyzes the synthesis of urea. 
C)  It catalyzes the hydrolysis of urea. 
D)  It catalyzes the hydrolysis of all amines. C

Question 3

In which type of inhibition does the inhibitor bind to the active site?

Accepted Answer

A)  cooperative inhibition 
B)  competitive inhibition 
C)  noncompetitive inhibition 
D)  selective inhibition 
A)  cooperative inhibition 
B)  competitive inhibition 
C)  noncompetitive inhibition 
D)  selective inhibition B

Question 4

Which of the following is true of isozymes?

Accepted Answer

A)  Their amino acid sequences are mirror images of one another. 
B)  They are a pair of enzymes which must both be present for enzyme activity to occur. 
C)  They are different forms of the same enzyme found in different tissues. 
D)  None of the above is true. 
A)  Their amino acid sequences are mirror images of one another. 
B)  They are a pair of enzymes which must both be present for enzyme activity to occur. 
C)  They are different forms of the same enzyme found in different tissues. 
D)  None of the above is true.

Question 5

Tyrosine-tRNA synthetase belongs to which group of enzymes?

Accepted Answer

A)  hydrolases 
B)  ligases 
C)  oxidoreductases 
D)  transferases 
A)  hydrolases 
B)  ligases 
C)  oxidoreductases 
D)  transferases

Question 6

Aspartate transaminase belongs to which group of enzymes?

Accepted Answer

A)  hydrolases 
B)  lyases 
C)  oxidoreductases 
D)  transferases 
A)  hydrolases 
B)  lyases 
C)  oxidoreductases 
D)  transferases

Question 7

Consider the following image depicting enzyme behavior.   Which of the following correctly characterizes the components of this model?

Accepted Answer

A)  A - enzyme, B - substrate, C - active site, D - E-S complex 
B)  A - substrate, B - active site, C - enzyme, D - E-S complex 
C)  A - active site, B - substrate, C - E-S complex, D - enzyme 
D)  A - substrate, B - enzyme, D - E-S complex, D - active site 
A)  A - enzyme, B - substrate, C - active site, D - E-S complex 
B)  A - substrate, B - active site, C - enzyme, D - E-S complex 
C)  A - active site, B - substrate, C - E-S complex, D - enzyme 
D)  A - substrate, B - enzyme, D - E-S complex, D - active site

Question 8

Transition-state analogs do which of the following?

Accepted Answer

A)  They help chemists verify the nature of the active site. 
B)  They inhibit enzyme activity. 
C)  They offer the possibility of creating designer enzymes. 
D)  All of the above are correct. 
A)  They help chemists verify the nature of the active site. 
B)  They inhibit enzyme activity. 
C)  They offer the possibility of creating designer enzymes. 
D)  All of the above are correct.

Question 9

Consider the following reaction.   Which classification would be correct for the enzyme that catalyzes this reaction?

Accepted Answer

A)  oxidoreductase 
B)  isomerase 
C)  transferase 
D)  ligase 
E)  hydrolase 
A)  oxidoreductase 
B)  isomerase 
C)  transferase 
D)  ligase 
E)  hydrolase

Question 10

Which of the following is commonly associated with protein modification?

Accepted Answer

A)  phosphorylation 
B)  dephosphorylation 
C)  both a and b 
D)  neither a nor b 
A)  phosphorylation 
B)  dephosphorylation 
C)  both a and b 
D)  neither a nor b

Question 11

Which of the following will cause the rate of enzyme activity to increase linearly?

Accepted Answer

A)  increasing the enzyme concentration 
B)  increasing the substrate concentration 
C)  increasing the temperature 
D)  increasing the pH 
A)  increasing the enzyme concentration 
B)  increasing the substrate concentration 
C)  increasing the temperature 
D)  increasing the pH

Question 12

Enzymes are classified into how many different major groups?

Accepted Answer

A)  4 
B)  6 
C)  8 
D)  10 
A)  4 
B)  6 
C)  8 
D)  10

Question 13

Which of the following is often true of the active site of an enzyme?

Accepted Answer

A)  It consists of amino acids near both the N-terminus and C-terminus. 
B)  It consists of amino acids which are adjacent to each other. 
C)  It consists of amino acids which not adjacent to each other. 
D)  None of the above are true. 
A)  It consists of amino acids near both the N-terminus and C-terminus. 
B)  It consists of amino acids which are adjacent to each other. 
C)  It consists of amino acids which not adjacent to each other. 
D)  None of the above are true.

Question 14

Which of the following is used in diagnosing infectious hepatitis?

Accepted Answer

A)  ALT 
B)  CPK 
C)  LDH 
D)  PHI 
A)  ALT 
B)  CPK 
C)  LDH 
D)  PHI

Question 15

In addition to proteins, which type of molecules sometimes function as enzymes?

Accepted Answer

A)  carbohydrates 
B)  DNA 
C)  lipids 
D)  RNA 
A)  carbohydrates 
B)  DNA 
C)  lipids 
D)  RNA

Question 16

Which of the following is the reason that trypsin is synthesized as trypsinogen?

Accepted Answer

A)  It is simpler to synthesize trypsinogen. 
B)  Trypsinogen is a more active enzyme than trypsin. 
C)  Trypsin would attack the body's natural proteins. 
D)  Trypsin is a larger molecule than trypsinogen. 
A)  It is simpler to synthesize trypsinogen. 
B)  Trypsinogen is a more active enzyme than trypsin. 
C)  Trypsin would attack the body's natural proteins. 
D)  Trypsin is a larger molecule than trypsinogen.

Question 17

Lactate dehydrogenase belongs to which group of enzymes?

Accepted Answer

A)  hydrolases 
B)  lyases 
C)  oxidoreductases 
D)  transferases 
A)  hydrolases 
B)  lyases 
C)  oxidoreductases 
D)  transferases

Question 18

What is the general name used when the product of a reaction sequence inhibits an earlier step in that sequence?

Accepted Answer

A)  cooperative inhibition 
B)  competitive inhibition 
C)  feedback control 
D)  stereospecificity 
A)  cooperative inhibition 
B)  competitive inhibition 
C)  feedback control 
D)  stereospecificity

Question 19

Which types of amino acids interact most strongly with metal ions?

Accepted Answer

A)  those with acidic side chains 
B)  those with basic side chains 
C)  those with nonpolar side chains 
D)  those with polar side chains 
A)  those with acidic side chains 
B)  those with basic side chains 
C)  those with nonpolar side chains 
D)  those with polar side chains

Question 20

Which of the following can cause enzyme activity to either increase or decrease?

Accepted Answer

A)  changing the temperature 
B)  increasing the substrate concentration 
C)  both a and b 
D)  neither a nor b 
A)  changing the temperature 
B)  increasing the substrate concentration 
C)  both a and b 
D)  neither a nor b

Exam 23: Enzymes

The following represents a transition-state in a certain reaction. Which of the following would be the best transition-state analog?

Which of following is true of urease?

In which type of inhibition does the inhibitor bind to the active site?

Which of the following is true of isozymes?

Tyrosine-tRNA synthetase belongs to which group of enzymes?

Aspartate transaminase belongs to which group of enzymes?

Consider the following image depicting enzyme behavior. Which of the following correctly characterizes the components of this model?

Transition-state analogs do which of the following?

Consider the following reaction. Which classification would be correct for the enzyme that catalyzes this reaction?

Which of the following is commonly associated with protein modification?

Which of the following will cause the rate of enzyme activity to increase linearly?

Enzymes are classified into how many different major groups?

Which of the following is often true of the active site of an enzyme?

Which of the following is used in diagnosing infectious hepatitis?

In addition to proteins, which type of molecules sometimes function as enzymes?

Which of the following is the reason that trypsin is synthesized as trypsinogen?

Lactate dehydrogenase belongs to which group of enzymes?

What is the general name used when the product of a reaction sequence inhibits an earlier step in that sequence?

Which types of amino acids interact most strongly with metal ions?

Which of the following can cause enzyme activity to either increase or decrease?

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