Enzymes(Biochemistry ) Questions and Answers

Question 1.  Tryprotophan synthetase of E.coli, a typical bifunctional oligomeric enzyme consist of
  1.    a protein designated A
  2.    two proteins designated A and B
  3.    a protein A and one-subunit a
  4.    a protein designated B
Explanation:-
Answer: Option B. -> two proteins designated A and B
Question 2.  Enzyme-driven metabolic pathways can be made more efficient by
  1.    concentrating enzymes within specific cellular compartments
  2.    grouping enzymes into free-floating, multienzyme complexes
  3.    fixing enzymes into membranes so that they are adjacent to each other
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 3.  Which of the following statements about enzymes or their function is true?
  1.    Enzymes do not alter the overall change in free energy for a reaction
  2.    Enzymes are proteins whose three-dimensional form is key to their function
  3.    Enzymes speed up reactions by lowering activation energy
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 4.  Which of the following (s) is/are serine proteases?
  1.    Chymotrypsin
  2.    Trypsin
  3.    Elastase
  4.    all of these
Explanation:-
Answer: Option D. -> all of these
Question 5.  What is the specificity of the Clostripain protease?
  1.    It cleave after Arg residues
  2.    It cleave after His residues
  3.    It cleave after Lys residues
  4.    None of the above
Explanation:-
Answer: Option A. -> It cleave after Arg residues
Question 6.  
The proteolysis rate enhancement by chymotrypsin (~1010 folds) corresponds to a reduction in activation energy of about
  1.    40 kJ/mol
  2.    49 kJ/mol
  3.    58 kJ/mol
  4.    88 kJ/mol
Explanation:-
Answer: Option C. -> 58 kJ/mol
Question 7.  Which of the following is false statement with regard to comparison between Serine and HIV proteases?
  1.    Both use nucleophilic attack to hydrolyze the peptide bond
  2.    Both require water to complete the catalytic cycle
  3.    Both forms an acyl-enzyme intermediate
  4.    Both show specificity for certain amino acid sequences
Explanation:-
Answer: Option C. -> Both forms an acyl-enzyme intermediate
Question 8.  In the enzyme-catalyzed reaction shown below, what will be the effect on substances A, B, C, and D of inactivating the enzyme labeled E2?
A ---(E1)---> B ---(E2)---> C ---(E3)--->
  1.    A, B, C, and D will all still be produced
  2.    A, B, and C will still be produced, but not D
  3.    A and B will still be produced, but not C or D
  4.    A will still be produced, but not B, C, or D
Explanation:-
Answer: Option C. -> A and B will still be produced, but not C or D
Question 9. . The role of Asp 102 and His 57 during trypsin catalysis is to
  1.    neutralize the charge on the other's side chain
  2.    keep the specificity pocket open
  3.    function as a proton shuttle
  4.    clamp the substrate into the active site
Explanation:-
Answer: Option C. -> function as a proton shuttle
Question 10. . The E.coli pyruvic acid dehydrogenase complex is reported to
  1.    decatalyze the oxidation of pyruvic acid to acetyl Co A and CO2
  2.    Catalyze the oxidation of pyruvic acid to acetyl Co A and CO2
  3.    retard the reduction of pyruvic acid to acetyl Co A and CO2
  4.    Catalyze the reduction of pyruvic acid to acetyl Co A and CO2
Explanation:-
Answer: Option B. -> Catalyze the oxidation of pyruvic acid to acetyl Co A and CO2
© Lakshya_Education.com, All Right Reserved.
Contact Us services