Ultimate Molecular Biology Quiz

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Ultimate Molecular Biology Quiz - Quiz

Do you understand molecular biology well? Take this molecular biology quiz, and see how much you know about this topic. Molecular biology studies the chemical and physical structure of biological macromolecules. Go for this quiz, and test your knowledge. Even if you miss out on some questions, we will help you with the correct answer. Try to get 100% on this quiz. If you find this quiz informative, share it with others interested in testing their knowledge on this topic.


Questions and Answers
  • 1. 
    Which of the following is not present in the core RNA polymerase? 
    • A. 

      B (Beta)

    • B. 

      B' (Beta prime)

    • C. 

      Sigma (o)

    • D. 

      Both (Beta) and (sigma)

  • 2. 
    An experiment was designed to obtain nonspecific transcription from both strands of a DNA molecule. Which of the following strategies would be most effective in achieving this? 
    • A. 

      Include the RNA holoenzyme in the reaction.

    • B. 

      Use the core enzyme of RNA polymerase.

    • C. 

      Enrich the preparation with sigma subunit

    • D. 

      Use intact DNA.

    • E. 

      Include the RNA holoenzyme in the reaction and using the core enzyme of RNA polymerase are both effective.

  • 3. 
    Which of the following techniques would be most useful in testing the ability of the core RNA polymerase to bind to the promoter? 
    • A. 

      Gel filtration

    • B. 

      S1 mapping

    • C. 

      Immunoblotting

    • D. 

      DNase footprinting

    • E. 

      Northern blotting

  • 4. 
    Which of the following statements is false regarding the sigma factor? 
    • A. 

      It does not have a DNA-binding domain.

    • B. 

      Interaction with the core enzyme unmasks the DNA-binding region.

    • C. 

      Subregions 2.4 and 4.4 are involved in promoter recognition.

    • D. 

      It can also bind to the nontemplate strand.

    • E. 

      It can bind to the -10 box.

  • 5. 
    Which of the following is true about the holoenzyme of RNA pol in an open complex? 
    • A. 

      The DNA is bound mainly to the sigma-subunit

    • B. 

      There is no interaction between the sigma factor and the -10 region.

    • C. 

      There are two Na+ ions in the core enzyme.

    • D. 

      Region 2.4 of the sigma-factor binds the -35 region.

    • E. 

      The DNA is bound mainly to the sigma-subunit, and there is no interaction between the sigma factor and the -10 region.

  • 6. 
    Dimethyl sulfate is used to 
    • A. 

      Cleave DNA molecules

    • B. 

      Denature or melt DNA promotes region

    • C. 

      Remove methyl groups from RNA

    • D. 

      Add methyl groups to DNA

    • E. 

      Promote the binding of RNA polymerase to DNA

  • 7. 
    Which of the following would most likely occur if an in vitro transcription assay is performed by using a cell extract containing an (alpha) subunit without the C-terminal domain? 
    • A. 

      Polymerase would become tightly associated with the promoter.

    • B. 

      Polymerase would become more susceptible to proteolysis.

    • C. 

      Transcription will be accelerated.

    • D. 

      Polymerase complex would be loosely associated with the promoter.

    • E. 

      Recognition of the UP element would be faster.

  • 8. 
    Place the following in the order that they occur during transcription initiation: 1- formation of open complex2- formation of closed complex3- promoter clearance4- synthesis of about 10 nucleotides 
    • A. 

      1,2,3,4

    • B. 

      2,1,4.3

    • C. 

      2,1,2,4

    • D. 

      3,1,2,4

    • E. 

      3,2,1,4

  • 9. 
    Which of the following techniques is suitable for the study of DNA: RNA hybrid formation during transcription? 
    • A. 

      DNA: protein crosslinking

    • B. 

      DNAase I footprinting

    • C. 

      DNA: RNA crosslinking

    • D. 

      Two-dimensional PAGE

    • E. 

      FRET analysis

  • 10. 
    Which of the following are characteristic of intrinsic terminator elements? 
    • A. 

      They contain an inverted repeat.

    • B. 

      They contain a hairpin loop.

    • C. 

      They contain several T's in the non-template strand of DNA.

    • D. 

      Only they contain an inverted repeat, and they contain a hairpin loop are correct.

    • E. 

      They contain an inverted repeat, they contain a hairpin loop, and they contain several T's in the non-template strand of DNA.

  • 11. 
    Which of the following is incorrect regarding rho-dependent terminators? 
    • A. 

      They contain several T's in the non-template strand.

    • B. 

      They consist of inverted repeats.

    • C. 

      They form hairpin loops.

    • D. 

      Rho binds to the growing transcripts.

    • E. 

      Rho has no helicase activity.

  • 12. 
    Which of the following does not have a DNA-binding domain? 
    • A. 

      Sigma-factor

    • B. 

      UP region

    • C. 

      Alpha-factor

    • D. 

      Beta

    • E. 

      Beta prime

  • 13. 
    Which of the following bond is lactose linked between glucose and galactose? 
    • A. 

      It is a glycoside bond.

    • B. 

      The linkage is through (beta)-1, 4 bond.

    • C. 

      It can be broken by (beta)-galactosidase.

    • D. 

      It is a covalent bond.

    • E. 

      All of the choices are correct.

  • 14. 
    If an operon is under negative control, it means that the operon is never operational.
    • A. 

      True

    • B. 

      False

  • 15. 
    In the absence of glucose, there will be a rapid accumulation of lactose in the following mutant: I- Oc Z+ Y-I- O+ Z+ Y-
    • A. 

      True

    • B. 

      False

  • 16. 
    The following is an example of a cis-dominant mutation: I-d O+ Z+ Y+ A-
    • A. 

      True

    • B. 

      False

  • 17. 
    Which of the following statements is true about a lac operon with the following genotype? I- Oc Z+ Y-I- O+ Z- Y-
    • A. 

      A repressor protein will be constitutively produced.

    • B. 

      (Beta)- galactosidase will be constitutively produced.

    • C. 

      A trans-dominant mutation is present.

    • D. 

      Permease will be constitutively produced.

    • E. 

      Both a repressor protein will be constitutively produced and a cis-dominant mutation is present.

  • 18. 
    Which of the following plasmids could be used to restore inducible regulation of (Beta)-galactosidase in this mutant: I+ Oc Z- Y+ A+? 
    • A. 

      I+ Oc Z- Y+ A+

    • B. 

      I+Oc Z- Y- A-

    • C. 

      I- O+ Z+ Y+ A+

    • D. 

      I- Oc Z+ Y+ A+

    • E. 

      Both I+ Oc Z- Y+ A+ and I+ Oc Z- Y- A- are correct

  • 19. 
    Which of the following organisms would produce functional lac products in the presence of IPTG? 
    • A. 

      Is Oc Z- Y+ A+

    • B. 

      Is Oc Z- Y- A-

    • C. 

      I+ O+ Z+ Y+ A+

    • D. 

      I- Oc Z+ Y+ A+

    • E. 

      Both Is Oc Z- Y+ A+ and Is Oc Z- Y+ A+ are correct.

  • 20. 
    Which of the following statements is true about a lac operon with this genotype? I-d O+ Z+ Y- A- 
    • A. 

      The operon is repressible.

    • B. 

      The operon is non-repressible.

    • C. 

      The mutation is cis-dominant.

    • D. 

      The operon is uninducible.

    • E. 

      None of the choices is correct.

  • 21. 
    Which of the following techniques is most useful in determining if RNA polymerase has initiated transcription from the lac DNA template? 
    • A. 

      Southern analysis

    • B. 

      DNA fingerprinting

    • C. 

      Run-off transcription assay

    • D. 

      DNA sequencing

    • E. 

      RACE

  • 22. 
    In an in vitro transcription assay to detect the level of transcription from a lac operon, one of the RNA precursors was tagged with a fluorescent label on the y-phosphate. Which of the following is a likely outcome if transcription occurred? 
    • A. 

      The level of fluorescence would increase along the new RNA strand.

    • B. 

      Each RNA would have a fluorescent tag on every other nucleotide.

    • C. 

      The level of fluorescence would be very high in the assay buffer.

    • D. 

      No fluorescence would be detected in the buffer at the end of the assay.

    • E. 

      All of the choices are possible.

  • 23. 
    Which of the following is most likely to occur if the level of glucose is low in a bacterial cell? 
    • A. 

      Cyclic-AMP levels will be depressed.

    • B. 

      CAP will assist in stimulating transcription of the lac operon if lactose is added

    • C. 

      CRP activity will be inhibited

    • D. 

      Both Cyclic-AMP levels will be depressed and CRP activity will be inhibited.

    • E. 

      None of the choices is correct.

  • 24. 
    Which of the following is true about the action of CAP at the lac promoter? 
    • A. 

      CAP monomer binds directly to the promoter, stimulating polymerase to bind

    • B. 

      CAP-AMP blocks the recruitment of polymerase to the promoter

    • C. 

      CAP blocks the (alpha) CTD of RNA polymerase

    • D. 

      Binding of the CAP-cAMP to the lac activator-binding site recruits RNA polymerase.

    • E. 

      CAP monomer binds directly to the promoter, stimulating polymerase to bind, and CAP blocks the (alpha) CTD of RNA polymerase

  • 25. 
    Which of the following is true about the regulation of the trp operon? 
    • A. 

      An aporepressor is involved.

    • B. 

      A corepressoris involved.

    • C. 

      Attenuation is one of the control mechanisms.

    • D. 

      A negative control is involved.

    • E. 

      All of the choices are true.

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