University of Houston BCHS 3304 Test 3 | Questions with
100% Verified Answers | Latest Update
Question:
About enzyme catalysis, which of the following is NOT true?
a. Enzyme catalysis leads to great enhancement of reaction
rates.
b. Enzymes are geometrically specific but not stereospecific.
(they are stereospecific)
c. Some enzymes require cofactors such as nicotinamide
adenine dinucleotide.
d. Enzymes drop free energy of activation but not ΔG of
reactions
e. All the above
Answer:
b. Enzymes are geometrically specific but not stereospecific.
(they are stereospecific)
Question:
Reactant I goes through two intermediate products (II and III) to become product IV. Based on the
following reaction coordinate, which is the rate limiting step? (look at the diagram)
a. I to II
b. II to III
c. III to IV
d. I to IV
Answer:
b. II to III
Question:
Enyme catalytic mechanisms may include______
a. Acid-base catalysis
b. Covalent catalysis
c. Metal ions catalysis
d. Preferential binding of the transition state complex
e. All the above
Answer:
e. All the above
Question:
RNAse A is a good example of ____ catalysis
a. Acid-base
b. Covalent
c. Metal ion
d. All of the above
, Answer:
a. Acid-Base
Question:
Within the lysozyme active site, Glu35 is in a hydrophobic environment and Asp52 is in a polar
environment. During the early stages of catalysis______
a. Glu35 is involved in general acid catalysis
b. Asp52 is involved in general acid catalysis
c. Glu35 is involved in covalent catalysis
d. Based on the local environment, Asp52 has a higher pKa
than Glu35
Answer:
a. Glu35 is involved in general acid catalysis
Question:
Like DIPF, Sarin is nerve agent which is used as a chemical weapon. It primarily targets _______.
a. Lysozyme
b. RNAse A
c. Serine Protease
d. Zymogen
e. Methyl transferase
Answer:
c. Serine Protease
Question:
Hg, Cd, and Co ions inhibit the enzyme Urease. Based on your knowledge, this suggests that _____.
a. Urease catalyzed reactions involves acid-base catalysis
b. Urease catalyzed reactions involves covalent catalysis
c. Urease catalyzed reactions involves metal ion catalysis
d. Urease catalyzed reactions stabilization of the transition
state
e. none of the above
Answer:
c. Urease catalyzed reactions involves metal ion catalysis
Question:
Among the following amino acid residues, which one is LEAST likely to carry out nucleophilic attack?
a. Ser
b. Cys
c. His
d. Asp
e. Val
Answer:
, Val (His carries out nucleophilic attack)
Question:
Many protease are produced as longer precursors. Why would this be the case?
a. Maintains a blocked or disordered active site until activated
by proteolysis or cleavage of the inactive precursor.
b. Prevention of the activation of the protease when
synthesized, this protecting the synthesizing organ.
c. Regulated activation of the protease when and where it is
required.
d. All of the above
Answer:
d. All of the above
Question:
A new serine protease was discovered that preferentially cleaves a peptide bond adjoining a
negatively charged side chain. Which of the following is true?
a. The specificity pocket would mimic that of chymotrypsin
b. The specificity pocket would mimic that of trypsin
c. The specificity pocket is likely lined with amino acid such as
Arg and Lys
d. It likely reacts much slower that chymotrypsin
e. Its likely reaction much faster than chymotrypsin
Answer:
c. The specificity pocket is likely lined with amino acid such as Arg and Lys
Question:
Which of the following would result in the greatest decrease in function of the catalytic triad found
in serine proteases?
a. Mutation to Ser, Cys, Asp
b. Mutation to Ser, His, Asp
c. Mutation to Cys, His, Asp
d. Mutation to Ser, His, Glu
e. Mutation to Cys, His, Glu
Answer:
b. Mutation to Ser, His, Asp
100% Verified Answers | Latest Update
Question:
About enzyme catalysis, which of the following is NOT true?
a. Enzyme catalysis leads to great enhancement of reaction
rates.
b. Enzymes are geometrically specific but not stereospecific.
(they are stereospecific)
c. Some enzymes require cofactors such as nicotinamide
adenine dinucleotide.
d. Enzymes drop free energy of activation but not ΔG of
reactions
e. All the above
Answer:
b. Enzymes are geometrically specific but not stereospecific.
(they are stereospecific)
Question:
Reactant I goes through two intermediate products (II and III) to become product IV. Based on the
following reaction coordinate, which is the rate limiting step? (look at the diagram)
a. I to II
b. II to III
c. III to IV
d. I to IV
Answer:
b. II to III
Question:
Enyme catalytic mechanisms may include______
a. Acid-base catalysis
b. Covalent catalysis
c. Metal ions catalysis
d. Preferential binding of the transition state complex
e. All the above
Answer:
e. All the above
Question:
RNAse A is a good example of ____ catalysis
a. Acid-base
b. Covalent
c. Metal ion
d. All of the above
, Answer:
a. Acid-Base
Question:
Within the lysozyme active site, Glu35 is in a hydrophobic environment and Asp52 is in a polar
environment. During the early stages of catalysis______
a. Glu35 is involved in general acid catalysis
b. Asp52 is involved in general acid catalysis
c. Glu35 is involved in covalent catalysis
d. Based on the local environment, Asp52 has a higher pKa
than Glu35
Answer:
a. Glu35 is involved in general acid catalysis
Question:
Like DIPF, Sarin is nerve agent which is used as a chemical weapon. It primarily targets _______.
a. Lysozyme
b. RNAse A
c. Serine Protease
d. Zymogen
e. Methyl transferase
Answer:
c. Serine Protease
Question:
Hg, Cd, and Co ions inhibit the enzyme Urease. Based on your knowledge, this suggests that _____.
a. Urease catalyzed reactions involves acid-base catalysis
b. Urease catalyzed reactions involves covalent catalysis
c. Urease catalyzed reactions involves metal ion catalysis
d. Urease catalyzed reactions stabilization of the transition
state
e. none of the above
Answer:
c. Urease catalyzed reactions involves metal ion catalysis
Question:
Among the following amino acid residues, which one is LEAST likely to carry out nucleophilic attack?
a. Ser
b. Cys
c. His
d. Asp
e. Val
Answer:
, Val (His carries out nucleophilic attack)
Question:
Many protease are produced as longer precursors. Why would this be the case?
a. Maintains a blocked or disordered active site until activated
by proteolysis or cleavage of the inactive precursor.
b. Prevention of the activation of the protease when
synthesized, this protecting the synthesizing organ.
c. Regulated activation of the protease when and where it is
required.
d. All of the above
Answer:
d. All of the above
Question:
A new serine protease was discovered that preferentially cleaves a peptide bond adjoining a
negatively charged side chain. Which of the following is true?
a. The specificity pocket would mimic that of chymotrypsin
b. The specificity pocket would mimic that of trypsin
c. The specificity pocket is likely lined with amino acid such as
Arg and Lys
d. It likely reacts much slower that chymotrypsin
e. Its likely reaction much faster than chymotrypsin
Answer:
c. The specificity pocket is likely lined with amino acid such as Arg and Lys
Question:
Which of the following would result in the greatest decrease in function of the catalytic triad found
in serine proteases?
a. Mutation to Ser, Cys, Asp
b. Mutation to Ser, His, Asp
c. Mutation to Cys, His, Asp
d. Mutation to Ser, His, Glu
e. Mutation to Cys, His, Glu
Answer:
b. Mutation to Ser, His, Asp
