2024-11-23T17:14:02+03:00[Europe/Moscow] en true <p>pH, temperature, radiation, osmotic pressure, salinity </p>, <p>o2, carbon, nitrogen, phosphorus </p>, <p>Cryophiles </p>, <p>Mesophiles </p>, <p>Thermophiles</p>, <p>Hyperthermophiles </p>, <p>Lag phase </p>, <p>Log or Exponential phase </p>, <p>Stationary phase </p>, <p>Death phase </p>, <p>Logarithmic manner </p>, <p>Direct count methods</p>, <p>hemacytometer </p>, <p>Viable count methods </p>, <p>Dilution plating methods </p>, <p>Turbidometric method</p>, <p>Spectrophotometer </p> flashcards
Microbiology 13

Microbiology 13

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  • pH, temperature, radiation, osmotic pressure, salinity

    physical factors affecting growth

  • o2, carbon, nitrogen, phosphorus

    chemical factors affecting growth

  • Cryophiles

    capable of growth and reproductionfrom -20oC to 10oC

  • Mesophiles

    –growth between 20oC- 45oC

  • Thermophiles

    growth at 50oC or higher

  • Hyperthermophiles

    growth between 80oC-113oC

  • Lag phase

    No increase in cell no. • Cells are synthesizing new components such as DNA replication, protein synthesis

  • Log or Exponential phase

    Rate of growth is constant • M.o. are growing and dividing at a maximal rate possible given the genetic potential, the nature of the medium or conditions of growth

  • Stationary phase

    Population growth ceases and the growth curve becomes horizontal • Total number remains constant due to a balance between cell division and cell death due to nutrient limitation, O2 availability for aerobic microbes and accumulation of waste products limit the growth

  • Death phase

    Detrimental environment changes like nutrient deprivation and the build up of toxic wastes lead to the decline in the number of viable cells characteristic of the death phase.

  • Logarithmic manner

    Most of the microbial population also dies in

  • Direct count methods

    counts both dead and live bacteria

  • hemacytometer

    direct count methods example

  • Viable count methods

    count live cells only.

  • Dilution plating methods

    viable count emthods example

  • Turbidometric method

    needs to be used together with dilution plate method initially to create a standard curve which can repeatedly be used later

  • Spectrophotometer

    Measures turbidity (% absorbed light) of bacterial suspension or % light transmitte