ch4and5 micro1420.txt

Card Set Information

ch4and5 micro1420.txt
2011-02-26 21:12:32

micro unit 2 ch 4 & 5
Show Answers:

  1. Microbial growth
    increase in the # of cells of a population
  2. Generation time
    aka doubling time: time it takes for a population to DOUBLE in #
  3. E. coli vs M. tuberculosis doubling time
    20MIN vs. 12HRS
  4. Biofilms
    many different microorgs that grow close togther.
  5. Example of biofilm
    Dental plaque, scum in drain, layers on rocks in stream
  6. useful biofilms
    Bioremediation to degrade harmful chems such as left over from OIL spills
  7. competition in biofilms
    • when bacterias compete for nutrients, it may lead to one bac synthesizing TOXIC chems that kill another bac
    • ie: mold synthesizes PENICILLIN which kills other bacteria
  8. cooperative behavior in biofilms
    one type of bac may produce nutrients for others to use & grow
  9. Slime layer
    • synth by bac in biofilms
    • useful for adherance to solid surface
    • protects against antibiotics & disinfectants
  10. closed vs open system for bac growth
    in closed system, nutrient NOT renewed & waste NOT removed, open is opp
  11. sporulation
    cells response to attempting to survive harmful conditions
  12. direct cell count
    does NOT distinguish b/w live & dead cells, viable cell count DOES
  13. Sterilization
    • process of removing or destroying ALL microorganisms & viruses
    • will even remove ENDOSPORES
  14. Disinfectants
    • germicides that are used to eliminate most pathogens, but may not kill some orgs and bac
    • for use on inanimate objects, called DISINFECTANTS
    • for use on animate objects (ie skin), called ANTISEPTICS
  15. Bacteriostatic
    prevents growth of bacteria BUT does not kill the bac
  16. Chemical Disinfectants that breakdown Proteins
    • Alcohols
    • Halogens
  17. Chemical Disinfectants that breakdown DNA
    • Ethylene Oxide
    • Aldehydes
  18. Chemical Disinfectants that breakdown Cytoplasmic Membrane
    • Biguanides
    • Quats
  19. Disinfectant plate
    uses bacterial growth on agar plate, with drops of disinfectant on plate. The WIDTH of the clear ring around the disinfectant shows how effective it is as a disinfectant