Catalytic strategies MCQ

• An enzyme accepts H + from hydronium and transfers it to an amino group of the substrate. The result is an increase in the rate of release of the product. This is an example of which of the following?

  A) Catalysis by approximation

  B) Covalent catalysis

  C) Acid-base catalysis

  D) Induced fit

  C
• Carbonic anhydrase uses:

  A) acid-base catalysis

  B) catalysis by approximation

  C) metal ion catalysis

  D) all of the above

  E) none of the above

  D
• Serine proteases use:

  A) acid-base catalysis

  B) catalysis by approximation

  C) covalent catalysis

  D) all of the above

  E) none of the above

  D
• Serine proteases:

  A) cleave peptide bonds between two serine residues

  B) cleave peptide bonds on the amino side of serine residues

  C) cleave peptide bonds on the carboxyl side of serine residues

  D) contain a serine residue in their active site

  D
• The catalytic triad of serine proteases contains:

  A) serine, alanine and glycine

  B) serine, histidine and asparagine

  C) serine, histidine and phenylalanine

  D) tyrosine, cysteine and methionine

  E) none of the answers above is correct 

  E
• What metabolic type of reaction involves the addition of a functional group across a double bond or the removal of a functional group to form a double bond?

  A) isomerisation

  B) group transfer

  C) ligation requiring ATP

  D) lyase

  E) None of the answers is correct.

  D
• Which of the following is correct concerning the following equilibrium?

  CO2 + H2O ⇌ H2CO3

  A) An increase in the concentration of CO 2 will result in a decrease of pH.

  B) The H2CO3 dissociates to H+ and bicarbonate ion, HCO3–.

  C) The majority of CO2 is transported to the lungs in the form of HCO3–.

  D) This reaction is catalysed by carbonic anhydrase.

  E) All of the answers are correct

  E
• Which one of the following is not among the six internationally accepted classes of enzymes?

  A) Hydrolases

  B) Ligases

  C) Oxidoreductases

  D) Polymerases

  E) Transferases

  D
• What metabolic type of reaction involves the cleavage of bonds by the addition of water?

  A) ligation

  B) isomerisation

  C) lyase

  D) oxidation-reduction

  E) None of the answers is correct.

  E
• Which of the following represents the most predominant form for the transfer of carbon dioxide in the blood?

  A) CO2

  B) H2CO3

  C) HCO3-

  D) CO32-

  E) None of the answers is correct

  C
• Carbonic anhydrase contains a _______ in its active site.

  A) Fe2+ ion

  B) Fe3+ ion

  C) Zn2+ ion

  D) coenzyme

  E) Mg2+ ion

  C
• Carbonic anhydrase:

  A) increases the pKa of water

  B) decreases the pKa of water

  C) protonates water

  D) protonates carbon dioxide

  E) none of the above

  B