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37 Cards in this Set
- Front
- Back
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What is a colony?
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visible mass of cells derived from one cell and grows on a solid medium
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What method is used to obtain pure cultures?
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streak plate method
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How do bacteria grow/reproduce?
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binary fission
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What is generation time?
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time it takes a prokaryotic cell to divide into 2 daughter cells
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What does generation time depend on?
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depends on species and metabolizing speed
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What is the lag phase?
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no increase in population, bacteria begins to tull up, preparing ezymes for metabolism
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What is the log phase?
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bacteria starts to grow/ reproduce and divide
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What is the stationary phase?
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limited nutrients, competition begins
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What is death phase?
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population begins to decrease with decrease of nutrients
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What is phase of prolonged decline?
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remaining bacteria eat dead bacteria in order to gain nutrients
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What is primary metabolite?
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protein neccessary for growth of cell (w/o = death)
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What is secondary metabolite?
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happens in stationary phase, actions taken by bacteria to facilitate growth.
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What does streptomyces griseus produce in stationary phase?
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streptomycin (antibiotic) competes for nutrients by killing other bacteria
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What does baccilus and clostridium produce in stationary phase?
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endospores
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What is the direct cell count?
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method used to count stained bacteria, adv= rapid/ disadv= not all cells counted are alive
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What is viable cell count?
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most accurate method to count live bacteria, disadv= not rapid. uses serial dilution
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What is the membrane filter technique?
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determines how much contamination is in dilute environments. gathers bacteria before its plated.
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What does a membrane filter collect?
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retains coliforms= bacteria found in lg. intestine. colony changes color when it ferments lactose and produces acid
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What is the spectrophotometer?
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machines that determines amount of bacteria based on turbidity (cloudiness)
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What are environmental factors used to classify bacteria?
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1-temperature
2-o2 requirements 3-pH 4-water availability |
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What are psychrophiles?
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live in very cold temp. optimum around 9C
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What are psychrotrophs?
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live in cold to medium temp. bacteria that spoils food in fridge. optimum temp around 28C
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What are mesophiles?
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live in middle temp. optimum temp around 38C. all pathogenic bacteria
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What are thermophiles?
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live in hot temp. optimum temp around 67C
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What are hyperthermophiles?
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archea that live in very hot temp. optimum around 98C.
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What is optimum temperature?
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an increase in 10C doubles enzyme production
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What is obligate aerobe?
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needs O2 to respire, creates ATP
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What is faculative aerobe?
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will respire with O2 if available or ferments if not
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What is obligate anaerobe?
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killed by O2
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What are microaerophiles?
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Uses small amounts of O2
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What is aerotolerant?
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does not use O2 to respire but can live in O2
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What do aerobes have that enables them to use O2?
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produces enzymes that transforms the superoxide produced into H202 and then into H20 and 02
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What are neutrophiles?
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live in middle ranges of PH, (5-8) (opt=7)
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What are acidophiles?
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ex. lactic acid bacteria, lives in PH below 5.5
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What are basophiles?
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live in PH above 8.5
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What is osmotolerant?
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can survive in relatively high salt solutions up to 10%
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What is halophile?
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archea that requires high levels of NACL in order to survive
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