Microbiology origins

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Microbiology origins
2011-03-15 18:08:58
Microbiology origins

Microbiology origins
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  1. Earliest life - when? In what?
    • 3.4 billion years ago
    • Found layered in rocks called stomatolites
  2. Evidence of life
    • From stomatolites
    • Isotope ratios (depleted 12CO2 in limestone)
  3. Models for early life (2)
    • Prebiotic soup - small organic molecules arise abiotically (lightning=catalyst and lipids spontaniously organize into micelles)
    • Metabolist Model - FeS catalyzes fixation of carbon = self-sustaining reaction (FeS still e- transport)
  4. Why RNA first? (3)
    • Has catalytic ability
    • regulates gene expression
    • synthesizes proteins
  5. What is a ribnuclease p/ribozyme? What is it's structure?
    • Ribonuclease P - is a ribozyme that acts as a catalyst in place of a protein
    • formed by homologous base pairing within RNA molecule that gives fxnl 2ndary structure
  6. During horizontal transfer what kind of gene is often transfered? What kind is not? Why?
    • Operational genes transfer - fxn independantly of other cell components, bring added fxn, confer selective advantage
    • Informational Genes (NOT)
  7. Pathogenicity Island (3 characteristics and associated with?)
    • associated with horizontal gene transfer
    • large set of genes grouped together, transfer as a unit, and pathological genes