practice exam 3

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practice exam 3
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2013-03-20 19:11:55
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genetics
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exam 3 practice problems
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  1. in E.coli, which terms accurately reflect the nature of replication of the chromosome?
    bidirectional and fixed point of initiation
  2. a single gene may produce two or more different RNAs by the process of
    alternative splicing
  3. DNA polymerase II adds nucleotides to
    the 3' end of the RNA primer
  4. DNA polymerase I is thought to add nucleotides
    in the place of the primer RNA after it is removed
  5. structures located at the ends of eukaryotic chromosomes are called
    telomeres
  6. which cluster of terms accurately reflects the nature of DNA replication in eukaryotes?

    A. fixed point of initiation, dibirectional,conservative
    B. fixed point of initiation, unidirectional,conservative
    C. multiple points of initiation, bidirectional,semiconservative
    multiple points of initiation, bidirectional, semiconservative
  7. the discontinuous aspect of replication of DNA in vivo is caused by
    the 5' to 3' polarity restriction
  8. Eukaryotes are dependent on ____ to complete synthesis of their chromosome ends.
    telomerase
  9. an intron is a section of
    RNA that is removed during RNA processing
  10. during DNA replication in eukaryotes, polymerase switching occurs



    A.     Pol a is replaced by Pol δ for
    elongation.

    B.     Pol δ is replaced by Pol a for elongation

    C.     Pol ais replaced by Pol β for elongation

    D.     Pol βis replaced by Pol α for elongation
    A
  11. what is the initiator triplet in both prokaryotes and eukaryotes? what amino acid is recruited by this triplet
    AUG, methionine
  12. select three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes



    A.    5'-capping, 3'-poly(A)
    tail addition, splicing

    B.   
    3'-capping,
    5'-poly(A) tail addition, splicing

    C.    removal of exons,
    insertion of introns, capping

    D.   
    5'-poly(A)
    tail addition, insertion of introns, capping

    E.    heteroduplex
    formation, base modification, capping
    A
  13. three posttransciptional modifications often seen in the maturation of mRNA in eukaryotes occur in which cellular organelle?
    nucleus
  14. when considering the initiation of transcription, one often finds consensus sequences located in the region of the DNA where RNA polymerase(s) bind. which are common consensus sequences in Eukaryotes?
    CAAT, TATA
  15. when scientists were attempting to determine the structure of the genetic code, Crick and co-workers foudn that when three base additions or three base deletions occured in a single gene, the wild-type phenotype was sometimes restored. these data supported the hypothesis that
    the code is triplet
  16. the term peptidyltransferase relates to
    peptide bond formation during protein synthesis
  17. holiday structure usually occur during
    meiosis in eukaryotes
  18. it has been recently determined that the gene for Duchenne, muscular dystrophy (DMD) is over 2000 kb in length; however, the mRNA produced by this gene is only about 14 kb long. What is a likely cause of this discrepancy?
    the introns have been spliced out during mRNA processing
  19. which of the following clusters of terms applies when addressing enhancers or silencers as elements associated with eukaryotic genetic regulation?



    A.   
    cis-acting, variable orientation,
    variable position 

    B.   
    trans-acting, fixed position, fixed
    orientation 

    C.    cis-acting, fixed position, fixed orientation

    D.    cis-acting, variable position, fixed orientation

    E.   
    trans- and cis-acting, variable
    position
    A. cis-acting, variable orientation, variable position
  20. which of the following chemical modifications is associated with increased gene activity?



    A.   
    acetylation of histones

    B.   
    methylation of DNA

    C.   
    deacetylation of histones
    A. acetylation of histones
  21. short RNA molecules can "silence" genes by
    bind to mRNAs and speed their degradation by facilitating the binding of enzymes that cleave the mRNA
  22. DNA methylation may be significant mode of genetic regulation in eukaryotes. Methylation refers to?
    addition of methyl groups to the cytosine of CG doublets
  23. transcription factors are proteins with at least two functional domains
    one activation domain, one repression domain
  24. what eukaryotic RNA polymerase is required for mRNA genes?
    RNA polymerase II
  25. one speaks of upstream active sequencing as being DNase hypersensitive. we would interpret this to mean that
    UAS is constitutively active, free of nucleosomes
  26. which one of these parts is not needed to specify the correct splicing of an intron?



    A.     5’ consensus
    sequence

    B.     3’consensus
    sequence

    C.     Promoter

    D.     Branch point
    c. promoter
  27. during elongation in translation, into which site in the ribosome does the aminoacyl tRNA enter?
    P site

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