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32 Cards in this Set
- Front
- Back
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4 phases of microbial growth
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lag - exponential growth (log growth) - stationary - death
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the log phase is a "flat" period of ____ & ____
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adjustment - enlargement
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binary fission during the lag phase is ____
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little (slow)
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the ____ ____ phase is a period of maximum division as long as cells have adequate ____ & a favorable ____
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exponential growth - nutrients - environment
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the ____ phase is when the rate of cell growth = rate of cell death
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stationary
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in stationary phase, cells die from depleted nutrients & ____ excretion of organic acids & waste fermentation products
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waste↑
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in the ____ phase, limiting factors intensify, cells die exponentially in the own wastes & log decrease
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death
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which phase would be most affected by an antibiotic targeting cell wall growth
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log growth phase
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when would endospores be most common
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stationary phase
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when would heat treatment be most/least effective
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log growth phase - death phase
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methods for counting CFUs when microbial numbers are too high
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serial dilution method
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in the serial dilution method colony forming unit (CFU) =
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bacterial cell
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in serial dilution method, # of CFU/mL =
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# of colonies x dilution factor (ex. 81 x 10⁵)
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2 methods for counting CFUs when microbial numbers are too low
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sample filtration - centrifuge sample
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in centrifuge sample, cells become concentrated into a ____
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pellet
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5 environmental influences on microbial growth
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temperature - O₂ - pH - electromagnetic radiation - barometric pressure
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3 cardinal temperatures
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minimum - maximum - optimum
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what is the best & fastest temperature for rate of growth & metabolism
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optimum temperature
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3 main temperature adaptation groups
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psychrophiles - mesophiles - thermophiles
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optimum temperature of psychrophiles
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15˚C - capable of growth at 0˚C
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optimum temperature of mesophiles
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20-40˚C - most human pathogens
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optimum temperature of thermophiles
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greater than 45˚C
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5 types of oxygen requirements
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aerobic - microaerophilic - facultative anaerobe - aerotolerant anaerobic - anaerobic
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growth location of aerobic
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top
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growth location of microaerophilic
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just below surface
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growth location of facultative anaerobe
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through out
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growth location of aerotolerant anaerobic
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bottom & some toward the top
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growth location of anaerobic
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bottom only
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3 optimum pH growth curves
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acidophile - neutrophile - alkalophile
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pH growth curves use ____ to stabilize the medium pH
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buffers
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excessive osmotic condition-type organism (hypersaline lake)
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halophiles
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what are the chemical nutrients needed for maintenance & growth of bacteria
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CHNOPS
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