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2011-05-06 10:32:41
Test Microbiology Chang

Test 3 Chang
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  1. The two double strands in DNA have ___ base sequences and form a _____
    Complementary ; double-helix
  2. What are the two types of DNA supercoiling and which is found predominantly in nature?
    Negative and positive; Negative found in nature
  3. Transcription begins at the ____ in Prokaryotes
    Promoter region
  4. The ____ region signals the start of RNA synthesis in Prokaryotes
  5. Stop codons are sometimes called ____, since there is no charged tRNA for the stop codons
    Nonsense codons
  6. If the enzyme primase was mutated, what would be the effect on DNA replication?
    No synthesis of RNA primer
  7. What is an operon?
    Group of related genes that are transcribed together to give a single polycistronic mRNA
  8. A group of related genes that are transcribed together to give a single polycistronic mRNA is called the ____
  9. For a bacterial genome, which factors are considered to predict a start codon?
    -10 region, -35 region and Shine Dalgarno sequence
  10. In an open reading frame, the stop codon is found where?
    The first encountered codon with a stop sequence
  11. For DNA replication to begin, what is required?
    An RNA primer
  12. What is a codon?
    A triple of bases on an mRNA molecule
  13. On the leading strand, DNA synthesis occurs ____ and on the lagging strand, DNA synthesis occurs ____
    Continuously ; discontinuously
  14. DNA is the template for _____ and ____ while mRNA is the template for ____
    Replication ; Transcription ; Translation
  15. DNA Polymerase I and III have ____ exonuclease activity while DNA Polymerase I also has ____ exonuclease activity
    3' to 5' ; 5' to 3'
  16. DNA polymerase I and III have ____ polymerase activity
    5' to 3'
  17. Which type of regulation controls the amount of enzyme?
    Transcriptional and translational
  18. Which type of regulation controls the activity of pre-existing enzymes?
    Post-translational regulation
  19. Transcriptional and translational regulation control the _______ while post-translational regulation control the ____
    Amount of enzyme ; activity of pre-existing enzymes
  20. Induction is a _____ control of transcription
  21. Repression is a _____ control of transcription
  22. What are effectors?
    Collective term for inducers and corepressors
  23. What is the positive control of transcription?
    Activator proteins bind to certain DNA sequence called activator binding site
  24. What is the activator binding site?
    A DNA sequence that activator proteins recognize and bind to in a positive control
  25. In a negative control, what happens when an inducer binds to the repressor?
    The genes are transcribed
  26. In a two component regulatory system, what is the function of sensor kinase and where is it found?
    Detects environmental signal and autophosphorylates ; found in cytoplasmic membrane
  27. Phosphorylated sensor kinase is involved in activation of _____ by providing the phosphate group
    Response regulator
  28. What is a regulon?
    Multiple operons controlled by the same regulatory protein
  29. In diauxic growth, lactose ____ the synthesis of b-galactosidase
  30. What happens in diauxic growth after glucose is exhausted?
    There is a lag phase due to the synthesis of b-galactosidase
  31. In diauxic growth, when growth resumes on lactose, growth rate is ___ than that on glucose
  32. Why can't attenuation be found in Eukaryotes?
    Because transcription and translation of Eukaryotes are uncoupled
  33. Which statements correctly describe attenuation?
    • The tryptophan operon is an example of attenuation
    • mRNA stem-loop structure and synthesis of leader peptide are determining factors
    • In attenuation, uncharged t-RNA makes translation stalled
  34. What is plasmid curing?
    A process by which plasmids from host cells can be removed
  35. What are the properties of signal sequences?
    • -usually 15-20 residues long
    • -found at the beginning of protein molecules
    • -signal the cell's secretary system
    • -keep the protein from folding
  36. What are chaperonins?
    Enzymes that assist in polypeptide folding but are not incorporated into proteins
  37. What is meiosis?
    • -Meiosis occurs in sperm cells and reproduction division
    • -Meiosis is a specialized form of nuclear division and halves diploid number to haploid number
  38. Mitosis in prokaryotic cells happens through the process of ____
    Binary fission
  39. RNA interference (RNAi) cleaves ____ and is found excusively in ____
    dsRNA ; Eukaryotes
  40. What is the major application of RNA interference (RNAi) in science?
    It is used in gene silencing
  41. In Eukarya, what are exons?
    Coding regions of DNA
  42. In Eukarya, what are introns?
    Non-coding regions of DNA
  43. How do prokaryotes manage longer DNA replication time than doubling time?
    By utilizing multiple replication forks
  44. DNA replication proceeds ____ and transcription proceeds _____
    5' to 3' ; 5' to 3'
  45. ____ in the small subunit of ribosome recognizes the Shine Dalgarno sequence
  46. Why is a polysome more efficient than a single ribosome?
    Because it can simultaneously translate a single mRNA faster
  47. What are release factors?
    Result in termination of protein synthesis (translation) in prokaryotes
  48. ______ result in termination of protein synthesis in prokaryotes
    Release factors
  49. In Eukaryotes, the genes for the large rRNAs are transcribed by _____
    RNA Polymerase I
  50. What are the characteristics of riboswitches?
    • -located at 5' end of mRNA
    • -analogous to negative control
    • -similar to protein recognizing a substrate
    • -found in Eukarya
  51. Which domain has telomeres and telomerase?
  52. What is the first acid in a bacterial protein?
  53. What are ribozymes?
    RNA molecules with enzymatic activity
  54. RNA molecules with enzymatic activity are called _____
  55. What are some properties of genetic elements?
    • -Viruses contain either RNA or DNA genomes
    • -Plasmids replicate separately from chromosome and most are circular
    • -Transposable elements can be inserted into other DNA and play a role in genetic variation
  56. What are transposable elements?
    Sequences or genes in DNA that can be inserted into other DNA and play a role in genetic variation
  57. The fragments of DNA on the lagging strand are called?
    Okazaki fragments
  58. In DNA replication, after removing the RNA primer, _____ fills in the gap
    DNA Polymerase I
  59. What is the function of DNA Lygase?
    Seals nicks in DNA
  60. _____ excises the RNA primer during DNA replication
    DNA Polymerase I
  61. In termination of transcription, where does intrinsic termination occur?
    Both Eukaryotes and Prokaryotes
  62. In termination of transcription, where does Rho-dependent termination occur?
    Only in Prokaryotes (and requires energy)
  63. In Archaea, where does transcription take place?
  64. What is an open reading frame?
    • -A sequence (from start to stop codon) of DNA or RNA that can be translated to give a polypeptide
    • -Usually represents one gene
  65. Archaeal and eukaryotic DNA is wound around clusters of histones, forming structures known as _____
    Nucleosome (or chromatin)
  66. What is the function of DNA Gyrase and what group does it belong to?
    • Introduces supercoils into DNA by making a double stranded break in DNA
    • Belongs to group of Type II topoisomerase
  67. What is quorum sensing?
    Mechanism by which bacteria assess their population density and controls gene expression based on cell density