Chemistry Quiz 3 Nov 14-2012

57 Questions | Total Attempts: 60

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Chemistry Quizzes & Trivia

Questions and Answers
  • 1. 
    Which of the following statements is false regarding competitive enzyme inhibitors?
    • A. 

      The inhibitor has a similar molecular structure as the natural substrate

    • B. 

      The inhibitor affects the Km

    • C. 

      The inhibitor affect is overcome at high concentrations of normal substrate

    • D. 

      The inhibo=itor affects Vmax

  • 2. 
    Vmax can be affected withouth alterinf Km in which of the following situations?
    • A. 

      Increase the amount of enzyme

    • B. 

      Presence of an irreversible inhibitor

    • C. 

      Substrate concentrations is in excess

    • D. 

      Presence of a competitive inhibitor

  • 3. 
    To assure that zero order kinetics s maintained in an enzyme reaction, the substrate concentration should be:
    • A. 

      Equal to the Km

    • B. 

      Less than the Km

    • C. 

      At least 10 times greater than the Km

    • D. 

      Equal to 1/Km

  • 4. 
    The point at which an enzyme reaction is proceeding at the greatest rate is:
    • A. 

      The Michaelis constant (Km)

    • B. 

      Zero order kinetics

    • C. 

      First order kinetics

    • D. 

      Point where the rate of the reaction is dependent on the substrate concentration

  • 5. 
    Isoenzymes are:
    • A. 

      Multiple molecular forms of an enzye family that catalze the same reaction

    • B. 

      Different enzymes which exhibit the same enzymatic specificity

    • C. 

      Multiple molecular forms of different enzymes which catalyze the same reaction

    • D. 

      Different enzymes which exhibit the same electrophoretic mobility

  • 6. 
    Ethanol treatment in methanol intoxication is an example of?
    • A. 

      Non-competitive inhibition

    • B. 

      Competitive inhibition

    • C. 

      Irreversible inhibition

    • D. 

      Enzyme induction

  • 7. 
    A non-competitive inhibitor:
    • A. 

      Increases Vmax and maintains Km the same

    • B. 

      Does not affect Vmax or Km

    • C. 

      Decreases Vmax and decreases Km

    • D. 

      Decreases Vmax and maintains Km

  • 8. 
    In calcium methods, specimens are acidified:
    • A. 

      To set pH for colour reaction

    • B. 

      To free bound calcium from protein

    • C. 

      To deproteinize specimen

    • D. 

      To analyze organic calcium only

  • 9. 
    A patient had a blood specimen collected in a heparin-containing tube for calcium and magnesium determination. Upon centrifugation, the serum appeared hemolyzed. How would this affect magnesium?
    • A. 

      There would be no effect on the magnesium value

    • B. 

      The magnesium would form complexes with the hgb end the results would indicate a false negative value

    • C. 

      The magnesium is incorporated into the bilirubin molecule, leading to a false negative value

    • D. 

      Because erythrocytes contain magnesium, hemolysis would increase its apparent value

  • 10. 
    In measuring iron, which of the following statement is most correct?
    • A. 

      The specimen is acidified in order to release iron from transferrin

    • B. 

      The specimen if acidified to oxidize Fe(3+)to Fe(2+)

    • C. 

      The specimen is acidified to release iron from transferrin and to oxidize Fe(3+) to Fe(2+)

    • D. 

      The specimen is acidified ot release iron from transferrin and to reduce Fe(3+) to Fe(2+)

  • 11. 
    Which of the following reagents is used to measure phosphorus?
    • A. 

      Cresolphtalein complexone

    • B. 

      Ammonium molybdate

    • C. 

      Ferrozine

    • D. 

      Arsenoazo II

  • 12. 
    Kinase enzymes                      while carboxylase enzymes                   
    • A. 

      Transfer a phosphate, remove a carboxyl group

    • B. 

      Remove hydrogen, add a carboxyl group

    • C. 

      Remove hydrogen, remove carboxyl group

    • D. 

      Remove phosphate, add carboxyl

  • 13. 
    The enzyme catalyzed reaction (below) requires what type of enzyme? A-X + B --> A + B-X
    • A. 

      Hydrolase

    • B. 

      Lyase

    • C. 

      Isomerase

    • D. 

      Transferase

  • 14. 
    A DNA ligase enzyme joins              group of a nucleotide in a DNA strand with               group of an adjacent nucleotide to from               bond
    • A. 

      Hydroxyl, phosphoryl, phospho-ester

    • B. 

      Carboxyl, amino, peptide

    • C. 

      Hydroxyl, hydroxyl, glycosidic

    • D. 

      Hydroxy, amino, amide

  • 15. 
    In the Jendrassik-Grof method for the determination of total bilirubin, the colour reaction involves which of the following reactants?
    • A. 

      Alkaline tartare

    • B. 

      Caffeine sodium benzoate

    • C. 

      Diazosulphanilic acid

    • D. 

      Ascorbic acid

  • 16. 
    Under specified conditions of pH and temperature, the international unit (IU) is defined as:
    • A. 

      The enzyme activity that ccatalyzes the conversion of 1umol of substrate in 1 min under standard conditions

    • B. 

      The enzyme activity that ccatalyzes the conversion of 1mol of substrate in 1 min under standard conditions

    • C. 

      The enzyme activity that ccatalyzes the conversion of 1umol of product in 1 min under standard conditions

    • D. 

      The enzyme activity that ccatalyzes the conversion of 1umol of product in 1 min under standard conditions

  • 17. 
    Which anticoagulant is the best anticoagulant for serum glucose analysis because it inhibits glycolysis?
    • A. 

      Sodium oxalate

    • B. 

      EDTA

    • C. 

      Sodium fluoride

    • D. 

      Heparin

  • 18. 
    8-hydroxyquinoline is added in the reagents for the analysis fo calcium to:
    • A. 

      Bind to calcium to form a complex that chelates to CPC

    • B. 

      Reduce interferences by magnesium ions

    • C. 

      Enhance color reaction of calcium with CPC

    • D. 

      Prevent percipitation of proteins at acid pH

  • 19. 
    Mutarotase is added to the reagent for which of the following monosaccharides?
    • A. 

      Galactose

    • B. 

      Glucose

    • C. 

      Mannose

    • D. 

      Fructose

  • 20. 
    Which of the following sets of results would be consistent with heart?
    • A. 

      Inc. CK, LD5, Inc. AST

    • B. 

      Inc. LD1 CK2 and LD

    • C. 

      Inc. alkaline phosphatase and GGT

    • D. 

      Inc. LD1 and CK3

  • 21. 
    Which of the following interferes with CK measurement?
    • A. 

      N-acetylcysteine

    • B. 

      Mg

    • C. 

      Calcium

    • D. 

      Phosphate

  • 22. 
    Analytical procedures that use enzymes as reagents:
    • A. 

      Requires excess substrate

    • B. 

      Add the enzyme(s) in excess

    • C. 

      Must be read every minute for 5 to 10 minute period

    • D. 

      Usually use protein percipitating reagents to stop the reaction

  • 23. 
    An absolute ion requirement for alkaline phosphatase analysis is:
    • A. 

      Magnesium, zinc

    • B. 

      Iron, magnesium

    • C. 

      Copper

    • D. 

      Pyridoxyl phosphate

  • 24. 
    Transamination of an ammino acide results in the:
    • A. 

      Formation of ammonia

    • B. 

      Formation of a new amino acid and a anew keto acid

    • C. 

      Formation of urea

    • D. 

      Formation of ammonia, carbon dioxide and water

  • 25. 
    Which of the following is the primary reagent used in the Jaffe reaction for creatinine?
    • A. 

      Alkaline copper sulfate

    • B. 

      Phosphotungstic acid

    • C. 

      Diacetyl monoxime

    • D. 

      Alkaline picric acid

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