Biol 251 lab 7

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Biol 251 lab 7
2014-04-27 17:48:50
Microbiology lab7 Biol251L

Lab 7
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  1. Why do different temperatures produce different growth rates?
    Because different type of bacteria require different temperature range to grow.
  2. Optimum temperature
    Temperature that bacteria growth is fastest
  3. Minimum temperature
    the lowest temperature that bacteria can survive
  4. Maximum temperature
    the highest temperature that bacteria can survive
  5. Turbidity
    Cloudiness of culture that is use in measure bacteria growth after exposed to certain temperature.
  6. Spectrophotometer
    A device that measure bacteria growth after being expose to certain temperature in response absorbance of light by the culture turbidity
  7. Optical density
    The higher the cells growth the higher the light will be absorbed in the culture
  8. Psychrophiles
    Organism that live in temperature below 20oC
  9. Psychrotrophs
    • Organism that prefer cold temperature but can survive in temperature around 35oC
    • They more likely to cause infectious diseases because their optimum temperature is between 15o C - 30o C
  10. Mesophiles
    • Organism that live in medium range temperature
    • From 15oC - 20oC to 37oC - 45oC
  11. Thermophiles
    • Heat loving organism
    • Above 45oC to 80oC
  12. Extreme thermophiles
    Organism that live in temperature between 80oC - 110oC
  13. Thermoduric
    Organism that like medium heat but can survive temperature up to 110oC
  14. Osmosis
    Diffusion/movement of water
  15. Water activity
    Osmotic pressure
  16. What is hypertonic? What happens as result of it?
    • More solutes in the environment then inside the cell
    • H2O will diffuse out of the cell
  17. What is hypotonic? What happens as result of it?
    • Less solutes in the environment then inside the cell.
    • Water will defuse inside the cell
  18. What is isotonic? What happens as result of it?
    • The solute amount is equal in the environment and inside the cell
    • No H2O movement
  19. Plasmolysis
    The cell will shrink and its membrane will pull away from its cell wall due to loss of water in hypertonic environment
  20. What salinity % range can non tolerant bacteria can survive in?
    3% - 5%
  21. Halotolerant
    Bacteria that can survive and grow in up to 11% salinity environment
  22. Halophiles
    • Salt loving organism
    • NaCl 15% - 30%
  23. Osmophiles
    Sugar loving organism
  24. Visible radiation
    Microwaves & radio waves
  25. Ionizing radiation
    Gamma ray & X ray
  26. Non-ionizing radiation
    UV light
  27. Pyrimidine dimers
    Damage to DNA caused by UV radiation that form covalent bonds between adjacent pyrimidines and cause kinks in the DNA.
  28. What are the variables we used in the UV radiation experiment?
    • Time of exposure
    • barrier  present/absent
    • Distance from light source
    • Wavelength we used 260 nm
  29. What are the standardized we used in the UV radiation experiment?
    • Distance
    • wavelength 260 nm
  30. strict aerobes
    Organism that require O2 to make ATP (survive)
  31. strict anaerobes
    Organism that will die as result of exposure to O2
  32. Facultative anaerobes
    Organism that will use O2 to grow if it available but if there is no O2, They will use other method to make ATP.
  33. Aerotolerants
    Organism that will not use O2 but will not die from it.
  34. Microaerophilic
    • Organism that require O2 in just the right amount.
    • Too much or too little O2 will kill them.
  35. What property does Bacillus megaterium have that staphylococcus aureus does not have that allow it to survive longer exposure to UV light?
    How does it work?
    • Endospore
    • Bound with acid soluble proteins that give it better protection from UV light