Microbiology 3-7

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Anonymous
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247621
Filename:
Microbiology 3-7
Updated:
2013-11-18 15:44:06
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Thurston
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Study guide 3-7
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  1. Characterize the following types of mutations and describe how the given agents cause them: Spontaneous Mutations-Tuatomerization
    occur through changing from one base into another type of base. Causing AC and GT base pairs. Either A,C,G, or T can change
  2. Characterize the following types of mutations and describe how the given agents cause them:Spontaneous mutations- Insertions
    Nucleotides are inserted incorrectly due to slippage on the newly synthed strand
  3. Characterize the following types of mutations and describe how the given agents cause them: Spontaneous mutations- Deletions
    Nucleotides are inserted incorrectly due to slippage on the template strand
  4. Characterize the following types of mutations and describe how the given agents cause them: Spontaneous mutations- Depurination
    comes from lesions in DNA, they lose their base and will not base pair normally. (APURINIC SITE)
  5. Characterize the following types of mutations and describe how the given agents cause them: Spontaneous mutations- Depyrimidization
    comes from lesions in DNA, they lose their base and will not base pair normally. (APYRIMIDIC SITE)
  6. Characterize the following types of mutations and describe how the given agents cause them: Induced mutations-DNA modifying agents
    Caused by chemical or physical stuff. Can modify bases and make them pair incorrectly. ALTER BASES CAUSING MISPAIR
  7. Characterize the following types of mutations and describe how the given agents cause them: Induced mutations-Intercalating agents
    Distort DNA to induce single nucleotide pair insertions and deletions. Mutagens insert between stacked bases, making loops
  8. Characterize the following types of mutations and describe how the given agents cause them: Induced mutations-UV light
    Forms thymine dimers between adjacent pyrimidines.
  9. Characterize the mutation-Forward
    Going from wild type to mutant
  10. Characterize the mutation-reversion
    going from mutant to wild type
  11. Characterize the mutation-suppressor
    reversion involving second mutation at a different site than the original mutation.
  12. Describe the following types of point mutations with respect to the changes they cause in the base sequence and the polypeptides that are produced: Silent
    Silent- Codon for A.A. >different codon for same A.A.
  13. Describe the following types of point mutations with respect to the
    changes they cause in the base sequence and the polypeptides that are
    produced:Missense
    Codon for A.A. > Codon for different A.A.
  14. Describe the following types of point mutations with respect to the
    changes they cause in the base sequence and the polypeptides that are
    produced:Nonsense
    Sense codon > Stop codon
  15. Describe the following types of point mutations with respect to the
    changes they cause in the base sequence and the polypeptides that are
    produced:Frameshift
    Insertion or deletion of 1 or more base pairs
  16. Explain what a conditional mutation is
    expressed only under certain environmental conditions
  17. Distinguish between a prototroph and an auxotrophic mutant
    Auxotrophic-unable to make an essential molecules, came from a mutation in prototrophs. Conditional phenotype
  18. Describe the effects of the following non coding sequence mutations: Operator
    repressor doesn't bind
  19. Describe the effects of the following non coding sequence mutations:Promoter
    RNA poly doesn't bind
  20. Describe the effects of the following non coding sequence mutations: tRNA & rRNA
    disrupt translation
  21. Describe the following methods and how they detect/select for mutations:Replica Plating
    Used for screening and detection of auxotrophs
  22. Describe the following methods and how they detect/select for mutations:Ames Test
    • Uses auxotrophic Salmonella
    • Reversion rate w/ mutagen > reversion rate w/o mutagen
    • Mammalian liver extract may be added.
  23. Discuss DNA repair mechanism: Excision repair
    • Nucleotide-UvrABC enconuclease removes damaged nucleotides and some on either side of the lesion. Section removed is filled by DNA poly I. Ligase joins fragments
    • Base- DNA glycosylases remove damaged or unnatural bases. AP endonucleases recognize damaged DNA and nick backbone of AP site, DNA Poly I removes damaged region, ligase fills it
  24. Discuss DNA repair mechanism:Direct repair (photoreactivation and removal of alkyl groups)
    Photoreactivation- repairs thymine dimers by splitting them apart with visible light (thru photolyase). Removal of alkyl groups by alkyltransferase or methylguanine methyltransferase.
  25. Discuss DNA repair mechanism:Mismatch repair
    MutS scans, MutH removes around mismatch, DNA poly replaces and it is sealed by ligase.

    DNA METHYLATION- Old DNA (template strand) gets methylated, new DNA doesn't
  26. Discuss DNA repair mechanism:Recombinational repair
    Repairs on both sides (damaged and paired base)RecA protein cuts and replaces it from a sister molecule
  27. Discuss DNA repair mechanism:SOS response
    • RecA protein initiates recombination repair
    • RecA protein acts as protease, destroys repressor protein and increases production of excision repair enzymes. Cell division is stopped. Highly error-prone repair used in life or death situations.
  28. Distinguish between: Vertical Gene transfer Vs. horizontal gene transfer

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