Molecular Biology Exam III

66 Questions | Total Attempts: 373

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Molecular Biology Quizzes & Trivia

This exam cover chapters 14,15,17, 18 and 24


Questions and Answers
  • 1. 
    Which of the following experiments was useful in determing the existence of introns in the adenovirus genome?
    • A. 

      DNA/DNA hybridization

    • B. 

      RNA/RNA hybridization

    • C. 

      R-looping experiments

    • D. 

      RT-PCR

    • E. 

      CDNA cloning experiments

  • 2. 
    You have isolated a new species of mRNA using an oligo-dT column. You then perform an R-looping experiment to determine if the gene encoding for your mRNA contains introns. Below is a representation of the electron micrograph results. Which of the followign can you conclude from your experiment?
    • A. 

      The gene contains no introns

    • B. 

      The gene contains one intron

    • C. 

      The gene contains two introns

    • D. 

      The gene contains three introns

    • E. 

      The results are inconclusive

  • 3. 
    The first two bases and the last two bases in the splicing signal consensus sequence are
    • A. 

      GT-AG

    • B. 

      GU-AG

    • C. 

      CU-AG

    • D. 

      GU-AC

    • E. 

      GT-TG

  • 4. 
    Which of the following is the name for the YEAST 40s particle where mRNA splicing takes place?
    • A. 

      Ribosome

    • B. 

      Nucleolus

    • C. 

      Spliceosome

    • D. 

      HnRNA

    • E. 

      R-loop

  • 5. 
    "Snurps" or snRNPs are composed of
    • A. 

      RNA

    • B. 

      Protein

    • C. 

      DNA

    • D. 

      RNA and protein

    • E. 

      DNA and RNA

  • 6. 
    The catalytic center of the spliceosome appears to include
    • A. 

      Mg2+

    • B. 

      U2 and U6 snRNP

    • C. 

      The branch point region of the intron

    • D. 

      Mg2+ and the branch point region of the intron

    • E. 

      Mg2+, U2, and U6 snRNP, and the branch point region of the intron

  • 7. 
    Which of the following is the first snRNP to bind during the assembly stage of the spliceosome cycle?
    • A. 

      U1

    • B. 

      U2

    • C. 

      U4

    • D. 

      U5

    • E. 

      U6

  • 8. 
    Which of the following snRNP is mismatched with its function?
    • A. 

      U1: base pairs with 5' splice site of mRNA

    • B. 

      U2: base pairs witht he conserved sequence at splicing branch point

    • C. 

      U4: base pairs with 3' splice site of mRNA

    • D. 

      U5: associates with last nucleotide in one exon and the first nucleotide in the next exon.

    • E. 

      U6: base pairs with 5' end of the intron

  • 9. 
    The binding of which of the following snRNPs to spliceosome requires ATP?
    • A. 

      U1

    • B. 

      U2

    • C. 

      U4

    • D. 

      U5

    • E. 

      U6

  • 10. 
    Spliceosomal lariat is
    • A. 

      Cowboy's lasso

    • B. 

      Texan lariat

    • C. 

      Hairpin RNA

    • D. 

      Stem and loop DNA

    • E. 

      Splicing intermediate

  • 11. 
    Please put the following steps of Cap synthesis in the correct order. (1) N7 of the capping guanine is methylated (2) The terminal phosphate is removed from the pre-mRNA(3) A capping GMP is added to the pre-mRNA(4) The 2'-O-methyl group of the penultimate nucleotide is methylated
    • A. 

      1,2,3,4

    • B. 

      1,4,3,2

    • C. 

      2,4,1,3

    • D. 

      2,3,1,4

    • E. 

      4,3,2,1

  • 12. 
    Which of the following is NOT a function of the mRNA Cap?
    • A. 

      Protects the mRNA from degradation

    • B. 

      Enhances translatability of the mRNA

    • C. 

      Enhances transport of the mRNA to the cytoplasm

    • D. 

      Enhances splicing of the mRNA

    • E. 

      Helps regulate expression of the mRNA from the promoter

  • 13. 
    Although snRNA U1 fucntions in the nucleus, it receives a 5' Cap to enhances its
    • A. 

      Binding to snRNPs

    • B. 

      Export to the cytoplasm

    • C. 

      Export to the ER lumen

    • D. 

      Export out of the cell

    • E. 

      Binding to the mature mRNA

  • 14. 
    Which of the following is the mRNA polyadenylation signal motif found in mammalian cells?
    • A. 

      AAGAAA

    • B. 

      AAUAAA

    • C. 

      AAUGGG

    • D. 

      UUAUUU

    • E. 

      GGAUUU

  • 15. 
    When does capping of the pre-mRNA occur?
    • A. 

      It is the first nucleotie added by RNA polymerase.

    • B. 

      It occurs before the mRNA reaches a chain length of 30 nt.

    • C. 

      It occurs after the poly (A) tail has been added

    • D. 

      It occurs after splicing has occurred.

    • E. 

      It occurs after export of the mRNA inot the cytoplasm

  • 16. 
    Which of the following is not required for mammalian cell polyadenylation of pre-mRNA?
    • A. 

      PAP

    • B. 

      CPSF

    • C. 

      PABII

    • D. 

      DNA polymerase I

    • E. 

      RNA polymerase II

  • 17. 
    Uncapped mRNA is much more stable than capped mRNA.
    • A. 

      True

    • B. 

      False

  • 18. 
    The 5' cap of mRNA has no effect on the translatability of the mRNA
    • A. 

      True

    • B. 

      False

  • 19. 
    Poly (A) tails are added to the 5' end of the mRNA molecule
    • A. 

      True

    • B. 

      False

  • 20. 
    The additon of poly (A) to mRNA seems to be important for its translatability.
    • A. 

      True

    • B. 

      False

  • 21. 
    RNA polymerase II transcription of a gene usually stops at the polyadenylation site.
    • A. 

      True

    • B. 

      False

  • 22. 
    Pre-mRNA must be cleaved before it is polyadenylated
    • A. 

      True

    • B. 

      False

  • 23. 
    Once a mRNA loses its poly (A) tail, it is imported back into the nucleus
    • A. 

      True

    • B. 

      False

  • 24. 
    Polyadenylation is not required for efficient transport of mRNA out of the nucleus
    • A. 

      True

    • B. 

      False

  • 25. 
    Once the poly (A) tail is added to the mRNA it is very difficult to remove
    • A. 

      True

    • B. 

      False