Flashcards in Extreme conditions Deck (23)
What is optimum growth temperature?
the temperature at which the growth rate is the highest
What is the maximum growth temperature?
highest temperature at which growth is possible
what is the minimum growth temperature?
lowest temperature at which growth is possible
What does it mean to be heat sensitive?
when the degree of tolerance to heat has a narrow range between minimum and maximum growth temperatures.
classification of organism that has an optimum growth temperature between 28 and 38 degrees celcius?
classification of organism that has an optimum growth temperature below 16 degrees celcius?
classification of organism that has an optimum growth temperature above 65 degrees celcius?
classification of organism that has an optimum growth temperature close to 100 degrees celcius?
Mesophilic temperature range?
20 - 45 degrees celcius
thermophile temperature range?
45 to 80 degrees celcius
psychrophile temperature range?
below 20 degrees celcius
What optimum temperature does many pathogenic mesophiles have?
37 degrees celcius which is normal human temperature.
True or false, psychrophilic spoilage bacteria do exist
characteristic of the cytoplasm of a microbe
it contains a variety of dissolved materials, The concentrations of which are often higher than those obtained in their environments
what is the selective permeable membrane?
it separates the intracellular and extracellular spaces.
it allows water to flow from a region of low solute concentration to a region of high solute concentration (osmosis)
What creates osmotic pressure and what contributes to it?
a high solute concentration inside the cell creates the osmotic pressure. and the higher the intracellular solute concentration, the greater the osmotic pressure
What causes an influx of water to a cell?
if the cell is placed in a medium of lower solute concentration
What causes an efflux of water to a cell?
if a cell is placed in a medium of higher solute concentration.
What is plasmoptysis?
the influx of water and the rapid increase in cell volume resulting in a rupture or explosion of the cell wall, leakage of cell material, and death of cell
What is bacteriocidal?
when bacterial cell death occurs from plasmoptysis.
What happens to the cell when there is efflux of water? what is this called?
1. cell will shrink
2. concentration of cellular contents will be reduced
3. disruption of the cell wall cell membrane interaction
4. decreased metabolic activity due to reduced intracellular water content.
its called plasmolysis
what is bacteriostatic?
prevention of growth of cell without killing it.