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37 Cards in this Set

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