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