biol251

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Author:
nadiaessaqi
ID:
138847
Filename:
biol251
Updated:
2012-03-01 00:56:18
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microbiology
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Description:
chap 7
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  1. binnary fission
    1.Chromosome divides2.Septum grows between cells3.Cells separate
  2. doubling time
    Doubling time is the time it takes a bacterium to do one binary fission starting from having just divided.And ending at the point of having just completed the next division.
  3. What are the 6 most common elements found inliving bacterial cells?
    • •Carbon•Hydrogen•Nitrogen*•Oxygen•Phosphorus*•Sulfur•
    • CNHOPS---96% ofDry weight of cells*limiting nutrient
  4. Define Autotroph and Heterotroph and describe
    the importance of glucose to living organisms.
    • heterptroph:takes in glucose from enviroment
    • autotroph:makes:own from co2(carbon fixation)
    • photosynthesis
    • chemolithoautotrophic:energy from rocks
  5. Describe different method’s bacteria use to get
    large and small molecules into their cells no endocytosis
    no endocytosis:a)walled cell is a barrier b)enzymes are transported outside of the wall c)enzymes hydrolize the bonds of the nutrients d)smaller molecules are transported outside the wall and cell membrane into the cytoplasm
  6. Describe different method’s bacteria use to get
    large and small molecules into their cells no phagocytosis
    protein channels or carriers passive or active
  7. Describe what the term ‘limiting nutrient’ means
    and how nutrient pollution occurs
    toxic waste products secreted and start dying. ph goes down and a decline in population this lasts a very long time
  8. lag phaseName and discuss the stages of a simplebacterial growth curve.
    1 lag phase is when they make all nessary enzymes when they are done log phase
  9. Name and discuss the stages of a simplebacterial growth curve log phase.
    expotential growth phase 2 log phase has all nessary things and grow with nutritions and enzymes
  10. Name and discuss the stages of a simplebacterial growth curve stationary phase
    3 stationary stage stays stable all the nutitents are used up ex N,K+,phosphate in enviroments. some r dying and some growing so its stable because it equals intself out.
  11. Name and discuss the stages of a simplebacterial growth curve dealth phase
    4thdealth phase toxic waste products secreted and start dying. ph goes down and a decline in population this lasts a very long time (the final outcome varies with culture)
  12. Discuss how osmotic pressure changes limit the
    growth of microorganisms and what will happen when placing bacteria in
    hypertonic and hypotonic conditions
    Hypotonic environments: Generally not harmful to bacteria Some bacteria can survive high osmotic pressure by increasing the solute concentration of their cytoplasm
  13. Discuss how osmotic pressure changes limit thegrowth of microorganisms and what will happen when placing bacteria inhypertonic and hypotonic conditions
    Hypertonic environments: Most bacteria shrivel (plasmolysis) and stop dividing. Inhibit bacterial growth ex drying: making sells hypertonic not very much water so when on dryed meat ex salty:bacteria is shiveraled up and u will digest only a few that doesnt bother u ex sugary:the water difuses into frosting and shrinks up when the water from the bateria goes in
  14. Define
    the terms halotolerant organism and halophilic organism
    • halotolerant the number of solutes or things produced in cytoplasm. you stoped water from rushing water out of cells example staphylococcus aureus
    • halophilicHalophilic bacteria are those that REQUIRE high concentrations of salt to survive
  15. Psychrophiles
    from freezing psychro(from cold)
  16. Mesophiles
    love middle these r average because alot like us. this is where we find all our pathogens because their optimum is out body temp
  17. thermophilis
    just above body temp about 150 almost boiling.
  18. hyperthermophile
    hyperthermophile extermemly hot
  19. cardinal temp
    cardinal temps consist of minimum optimum and maximum on the types of protein and enzymes u have. determined from genes
  20. Acidophiles
    Acidophiles - 0-6
  21. neutrophiles
    Neutrophiles- 6-8
  22. alkalophiles
    •Alkalophiles - 8-14
  23. what do bacteria have for low and high ph enviroments?
    •Bacteria that live at high and low pH have mechanisms to keep the pH of cytoplasm around neutral
  24. obligate aerobes
    high oxygen requirement
  25. obligate anaerobes
    low o2 requirement
  26. facultative anaerobes
    • Facultative bacteria gather mostly at the top, since aerobic respiration
    • is the most beneficial one; but as lack of oxygen does not hurt them,
    • they can be found all along the test tube.
  27. microaerophiles
    Microaerophiles gather at the upper part of the test tube but not at the top. They require oxygen but at a low concentration.
  28. Discuss the ways in
    which oxygen is toxic
    Oxygen reacts with other molecules in the cell to produce toxic forms of oxygen–Singlet oxygen–Superoxide radical–Hydrogen peroxide–Hydroxyl radical (OH
  29. how bacteria have
    evolved ways to overcome its toxcicity
    Enzymes used to detoxify active oxygen compounds–Superoxide dismutase–Catalase–Peroxidase–Vitamin C–Vitamin E

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