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Power Point Lecture Notes Bacterial Reproduction and Growth

Binary Fission. Bacteria ___________________ by binary fission. Nucleus replicates, cell elongates and divides into two identical cells.Results in __________________ bacterial growth.. Generation Time. Time it takes for a bacterial cell to divideand __________________ its population.. Generati

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Power Point Lecture Notes Bacterial Reproduction and Growth

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    1. Chapter 4 Power Point Lecture Notes Bacterial Reproduction and Growth

    2. Binary Fission Bacteria ___________________ by binary fission. Nucleus replicates, cell elongates and divides into two identical cells. Results in __________________ bacterial growth.

    3. Generation Time Time it takes for a bacterial cell to divide and __________________ its population.

    4. Generation Time Problem: Streptococcus lactis has a generation time of 30 minutes. Four organisms were inoculated into a milk Sample, and the sample was allowed to sit for 3 hours before a total bacterial count was taken. How many organisms were in the milk sample at the end of 3 hours?

    5. Generation Time Base number is 2. Exponent = 6. The number of times one bacteria divides/hour times the number of hours. 26 or 2 x 2 x 2 x 2 x 2 x 2 = 64. 3. Total number of bacteria at the end of 3 hours is calculated by multiplying the value for one bacteria (64) times the number of bacteria in the original sample. 4 x 64 = 256 bacteria.

    6. Growth Phases Lag Phase Log or Exponential Phase - produces most symptoms of disease; most susceptible to ______________________ Stationary Phase ____________________________ Phase

    7. Temperature Classification Psychrophiles – 0-20 degrees C. ____________________ – 20-40 degrees C. Thermophiles – >40 degrees C.

    8. pH Requirements Most bacteria like neutral pH (7.0) _________________ can tolerate lower pH and are used in the production of acidic food products.

    9. Oxygen Requirements Oxygen is ________ to most cells because some forms of it are very reactive. Organisms that grow in oxygen have ______________ that allow them to break down toxic forms of oxygen. __________________ don’t produce the enzymes. They cannot live in an environment with oxygen.

    10. Oxygen Requirements O2- + O2- + 2H+ superoxide dismutase H2O2 + O2 H2O2 catalase 2H2O + O2 H2O2 + 2H+ peroxidase 2H2O To survive in oxygen, bacteria must have one or more _____________ (superoxide dismutase, catalase, or peroxidase)

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