quiz 3-4-15 Flashcards
(35 cards)
bacterial growth can be measured by two ways
quantitatively and qulitatively
how do bacteria cells divided?
by binary fission
if you observe a sample sight you are checking its?
turbity
when measuring the amount of light absorbed or transmitted its proportional to the number of bacterial cells in the solution sample you are using a what?
spectrophotometer
a device used to electronically count cells as they pass thought the device?
coulture counter
manual cell count with a microscope
petroff hausser counting chamber
what method is one of the simplest methods of estimating the size of population?
turbidometry. it relies on the simple observation that a tube of clear nutrient solution becomes cloudy, or turbid, as microbes grow in it
what is on of the disadvantages of using a spectrophotometer?
it is difficult to discriminate between live and dead cells
how does the spectrophotometer work
it measures the ability of cells to scatter light as it passes through a liquid culture, through a process known as absorbance.
this involves counting the numberof cells in a sample microscopically, using a cytometer
direct or total cell count
what is the disadvantages of a total cell count
it cannot determine the difference of live or dead cells.
as the cells pass through a tiny pipette they trigger an electronic sensor that registers their numbers, what method is this
the coulter counter
what are the disadvantages are noted when using the Petroff Hausser counting chamber
difficult to discriminate between live and dead bacteria. not possivle to give a number for viable cells
during what phase are cells metabolically active, but not reproducing yet
the lag phase
what phase are the cells reproducing at an exponential rate
log phase
during what phase are the cells reproduction the same as the dying rate
stationary phase
at what phase are the cells dying off at an exponential rate
death phase
what is the time it takes for the population to double, genetically determined
generation time
what is the alternative growth chamber called that is a continuous culture system. it provides a steady stream of new nutrients and siphons off the used old bacterial cells. it prevents the culture form entering the death phase
the chemostat
what organism can not grow with out oxygen
obligate aerobe
what type of organism is an anerobe but does not require oxygen for its metabolism and is capable of growth in the absence of oxygen
facultative anerobe
what organism does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it ( 1-15%)
microaerophile
what organism lacks the enzyme for processing toxic oxygen
strict anaerobe
what organism does not utilize oxygen but can survive and grow in its presence
aerotolerant anaerobe
