Biochemistry Lab Final Question

77 Questions | Total Attempts: 887

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Chemistry Quizzes & Trivia

Questions are from sample quizzes and final


Questions and Answers
  • 1. 
    The term "blotting" refers to:
    • A. 

      Running the gel in the presence of SDS

    • B. 

      Digesting the DNA with restriction enzyme

    • C. 

      Transfer of biomolecules to an immobilizing membrane

    • D. 

      Disrupting the disulfide bonds of proteins in the presence of (beta) mercaptoethanol

  • 2. 
    Check all choices that do not belong to transfer buffer:
    • A. 

      Methanol

    • B. 

      Tris-buffer

    • C. 

      SDS

    • D. 

      Acetone

    • E. 

      Glycine

    • F. 

      2-mercaptoethanol

  • 3. 
    Which reagent was used for total protein detection in your Western blot lab? 
    • A. 

      Ninhydrin spray

    • B. 

      Silver stain

    • C. 

      Colloidal gold reagent

    • D. 

      Copper stain

  • 4. 
    RNA blot refers to:
    • A. 

      Western blot

    • B. 

      Northern blot

    • C. 

      Southern blot

    • D. 

      Eastern blot

  • 5. 
    What are the basic steps required for biological molecules' detection using western blot technique? 
    • A. 

      Electrophoretic separation of protein

    • B. 

      Transfer and immobilization onto a membrane

    • C. 

      Binding of probe molecule to the target molecules on the membrane

    • D. 

      Visualization of bound protein

  • 6. 
    The mobility of portein bands in Western blotting is from anode (postive pole) to cathode (negative)
    • A. 

      True

    • B. 

      False

  • 7. 
    Most proteins have postive charge above pH 7.0
    • A. 

      True

    • B. 

      False

  • 8. 
    Blocking step in western blot detection is used to increase nonspecific binding
    • A. 

      True

    • B. 

      False

  • 9. 
    Which of the following is the proper component sequence in western blotting: 
    • A. 

      Fiber pad, filter paper, nitrocellulose membrane, gel, filter paper, fiber pad

    • B. 

      Fiber pad, nitrocellulose membrane, filter paper, gel, filter paper, fiber pad

    • C. 

      Fiber pad, filter paper, gel nitrocellulose membrane filter paper, fiber pad

    • D. 

      Fiber pad, nitrocellulose membrane, filter paper, gel, filter paper, fiber pad

  • 10. 
    The use of methanol in transfer buffer of western blotting is
    • A. 

      To increase negative charge of proteins to be transferred

    • B. 

      To dissociate the SDS from proteins and facilitate to move from gel to NC membrane

    • C. 

      To increase the dielectric constant

    • D. 

      Methanol has nothing to do with western blotting

  • 11. 
    Bell shape curve in an enzyme characterization is a represenative of: 
    • A. 

      PH only

    • B. 

      Temperature only

    • C. 

      Enzyme concentration only

    • D. 

      A and c

    • E. 

      A and b

  • 12. 
    What will be the inital velocity (Vo) for an enzyme that has Km =2s
    • A. 

      1/3 Vmax

    • B. 

      1/2 Vmax

    • C. 

      2/3 Vmax

  • 13. 
    Which of the following statement(s) is ture about lysozyme enzyme?
    • A. 

      Provide defense mechanism against bacterial infection

    • B. 

      Cleaves the glycosidic bond

    • C. 

      Eggwhite is the source for this enzyme

    • D. 

      All of the statements are true

  • 14. 
    One international unit of an enzyme is defined as the amount that catalyzes:
    • A. 

      The formation of one mmol of product in one min

    • B. 

      The formation of one micromol of product in one min

    • C. 

      The formation of one mol of product in one min

    • D. 

      The formation of one micromol of product in one hour

  • 15. 
    When [S] <
    • A. 

      The reaction is in zero order of reaction

    • B. 

      The reaction is in first order of reaction

    • C. 

      The product formation is directly related to the substrate concentration

    • D. 

      It is the substrate concentration that equals the Km estimate

    • E. 

      B and c

  • 16. 
    If Vmax = 150 micromol/sec and Km = 2mM, what is the initial velocity at  [S]= 10 mM? 
    • A. 

      125 micromoles/sec

    • B. 

      91 micromoles/sec

    • C. 

      125 micromol/min

    • D. 

      300 micromol/sec

  • 17. 
    Wht is the v/Vmax ratio if [S]=3Km?
    • A. 

      75

    • B. 

      0.75

    • C. 

      0.25

    • D. 

      None

  • 18. 
    In the last experiment, you added lysozyme just before recording the absorbance reading. At the end of reaction, you noticed clear assay solution. What could be the reason? Is it..
    • A. 

      The enzyme cleaves the hydrogen bond and disrupts the cell wall that becomes clear

    • B. 

      The enzyme cleaves the disulfide bond and disrupts the cell wall that becomes clear

    • C. 

      The enzyme cleaves the glycosidic bond and disrupts the cell wall that becomes clear

  • 19. 
    Enzymes increase the rate of reaction by:
    • A. 

      Increasing the free energy of activation

    • B. 

      Increasing the free energy change of the reaction

    • C. 

      Decreasing the nergy of activation

    • D. 

      None of the above

  • 20. 
    A 0.2 ml pure Muramidase (2.5 mg/ml) hydrolyzed 0.2 mmol of cell wall in 5 minutes. What is the specific activity? 
    • A. 

      40 micromole/min/mg

    • B. 

      0.04 millimol/min/mg

    • C. 

      80 micromol/min/mg

    • D. 

      None of the above

  • 21. 
    Modified by a suitable inhibitor
    • A. 

      Km

    • B. 

      Vmax

    • C. 

      Ki

  • 22. 
    Changed in the presence of competitive inhibitor 
    • A. 

      Km

    • B. 

      Vmax

    • C. 

      Ki

  • 23. 
    Changed in the presence of noncompetitive inhibitor 
    • A. 

      Km

    • B. 

      Vmax

    • C. 

      Ki

  • 24. 
    Changed in the presence of uncompetitive inhibitor
    • A. 

      Km

    • B. 

      Vmax

    • C. 

      Ki

  • 25. 
    Gives approximate substrate concentration within the cell 
    • A. 

      Km

    • B. 

      Vmax

    • C. 

      Ki

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