Micro Final Ch27

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Micro Final Ch27
2011-05-06 15:22:32

Chapter 27 - Environmental Microbiology
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  1. What is a Lichen?
    A mutually beneficial relationship between a fungus and algae (or cyanobacteria).
  2. How is the fungus benefitted in a Lichen?
    It receives carbohydrates (sugars).
  3. How is the algae benefitted in a Lichen?
    It receives minerals, water, and protection from the fungus.
  4. Where can Lichens grow?
    In places that would inhibit most organisms, like the surfaces of a rock.
  5. How much bacteria does groundwater contain? Why?
    Very few, most microbes become trapped in the soil as the water seeps through.
  6. When is risk of groundwater contamination at its highest?
    When human activity bypasses the filtering action of the soil (wells, broken septic tanks).
  7. When is surface water most highly contaminated? Why?
    After rainfall, large numbers of soil microbes get washed into lakes and rivers.
  8. How long does it take for a body of water return to normal after contamination of rainfall?
    72 hours.
  9. What percent of all infections worldwide are due to contaminated water? How many people die worldwide each year from these infections?
    80%, 2 million.
  10. Why are children under 5 most effected by water related infections?
    They're immune systems are not developed enough yet, they're more susceptible to dehydration and shock that occurs due to diarrheal diseases.
  11. What is a coliform?
    Facultatively anaerobic, gram-negative, non-endospore forming rod that ferments lactose to acid and gas withing 48 hours at 35 Degrees Centigrade.
  12. What are two examples of coliforms?
    E. coli, Proteus.
  13. Where are most coliforms found?
    The intestinal tracts of mammals.
  14. Why are we worried about coliforms in our food and water?
    Coliforms are present in fecal material, and their presence could indicate the presence of other pathogenic microbes in food and water.
  15. What is the goal of municipal water treatment?
    To produce water free of pathogens.
  16. What are the three steps to Water Treatment?
    Flocculation, Filtration, Disinfection.
  17. What is Flocculation?
    Raw water is mixed with Flocculant (like alum) which binds to the bad things in water and clumps them together. Then it is transferred into a tank where the clumps fall out of the solution.
  18. What is Filtration?
    Water is passed through a filter of sand or crushed coal which removes the passageway of microbes (especially cysts of protozoa).
  19. What is Disinfection?
    Water is disinfected by chlorine (~1ppm).
  20. What is Arkadelphia's source of water?
    Ouachita River.