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Micro Ch 6
Chap 6 microbial growth study questions
57
Microbiology
06/26/2010

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Term
The ability of microbes to utilize N2, as a nitrogen source is called....
Definition
nitrogen fixation
Term
bacterial growth refers to an increase in the ____ of bacterial cells
Definition
number
Term
an unknown organism grows at the top of a tube of thioglycolate broth.. This organism is _____ for oxygen requirements
Definition
aerobe
Term
salt agar tends to inhibit the growth of most organisms except staph. this is an example of _____ media
Definition
selective
Term
this method , cells are added to melted agar, and poured into a dish
Definition
pour plate method
Term
bacteria reequire nitrogen for the synthesis of
Definition
proteins
Term
what do all these bacteria have in common? Bacteria in the rumen of cattle, sheep bacteria in a sewage treatment plant, bacteria growing in the middle ear of chronic otitis, bacteria on the teeth
Definition
bacteria are most likely growing in biofilms...
Term
an organism that grows both in the presence and the absence of o2 and uses oxygen when it is avail
Definition
facultative anaerobe
Term
culture medium consisting of agar, peptone, and beef heart extract..
Definition
complex medium
Term
niacin, when added to a medium would be considered
Definition
organic growth factor
Term
martian soil is inoculated into a glucose-containing med. the radioactive form of c, is used in the glucose. after incubation for 5 days, what provides evidence suggesting there is life on mars
Definition
radioactive carbon dioxide (conversion of c as glucose to c as co2 indicates the metabolism...thus life
Term
a medium containing lauryl sulfate inhibits growth of g-pos bacteria.. theis medium is
Definition
selective,
Term
a medium that inhibits the growth of certain bacteria while permitting the growth of others is described as
Definition
selective
Term
to look for bacteria that degrade petroleum, a culture med contining crude oil, sodium nitrate, phosphate buffer and magnesium sulfate is inoculated with soil.. this medium is
Definition
complex medium
Term
if there is not a formula for crude oil, the medium would be described as
Definition
complex medium
Term
what is the third step in binary fission
Definition
inward growth of membrane
Term
which biosafety leve, has ... open lab benchtop, gloves, lab coat, and face prtotection
Definition
2
Term
psychrotrophic org are often responsible for food spoilage in refrigerated foods, t or f
Definition
true
Term
t or f... adding salts to a solution increases osmotic pressure and is used to preserve food
Definition
true
Term
microaerophiles do not require oxygen for growth t or f
Definition
false
Term
aerotolerant organisms can grow in the presence of oxygen because their cell wall protects them from toxic prod of oxygen... t or f
Definition
false
Term
microaerophiles do not require oxygen for growth
Definition
false
Term
in a direct microscopic cnt, dead cells are easily differenctiated from live cells t or f
Definition
false
Term
why is homemade potato salad refig overnight and served without any cooling on a warm day bad?
Definition
lg volume of pot salad is probably never completely cooled before serving. second not keeping it cold the next day will allow more bactria to grow.
Term
what is the disadvantage of using turbidity to estimate the number of viable bact cells in a broth
Definition
turbidity method counts dead celss as well as those that are viable and turbidity cannot be used on very dilute population
Term
slower growing bact would have a ____ slope than those with a faster generation time
Definition
greater slope (therefore; faster-growing bacteria would have a greateater slope than would those with a slw gen time
Term
t or f, psychrotrophic org are often responsible for food spoilage in refrigerator
Definition
true
Term
adding salts to a solution increases the osmotic press and is used as a preservative t or f
Definition
true
Term
microaerophiles do not require oxygen for growth
Definition
false
Term
aerotolerant org can grow in a the presence of oxygen because their cell wall protects them from toxic products of oxygen
Definition
false
Term
during the stationary phase, bacteria cont to undergo binary fission
Definition
true
Term
candle jars work well for cultivating anaerobic bacteria t or f
Definition
false
Term
when the spread plate tech is used to inoculate culture media some colonies form within the agar- t or f
Definition
false
Term
in a direct microscopic cnt, dead cells are easily diff from live t or f
Definition
false
Term
turbidity or cloudiness of a cell culture measured by spectophotometry is useful in detecting sm amt of microbial contamination in liq t or f
Definition
false
Term
cells growing in a rich med will have a steaper log phase slope than will those growing in a nutrient-poor med t or f
Definition
true
Term
shrinking of the cells cytoplasm in response to osmotic loss is called
Definition
plasmolysis
Term
the enzyme ___ catalyzes the conversion of peroxide to water and oxygen...
Definition
catalase
Term
the ___ is the most common tech used to obtain pure cultures of microbes (3 words)
Definition
streak plate method
Term
bacterial growth refers to an increase in the _____
Definition
number of bacterial cells
Term
an unknown org grows at the top of a tube of thioglycolate broth, the org is best described as..... for oxygen req
Definition
aerobe
Term
salt agar tends to inhibit the growth of most organisms except staph.. this is ____ media
Definition
selective media
Term
in a ____ cells are added to melted agar
Definition
pour plate
Term
a type of cell to cell communication that allows bact growing in biofilms to communicate and coordinate their activity is known as ____
Definition
quorum sensing
Term
in a pour pl tech, 32 bacterial colonies are counted on the 10 (-2) dilution of milk... how many bacteria were in the org milk
Definition
3200
Term
infections concerd with biofilms ... the bacteria in biofilms are more likely to be __________
Definition
resistant to antibiotics
Term
what tech will allow you to get isolated colonies on agar
Definition
useing a streak plate technique to inocultae
Term
a medium containing lauryl sulfate inhibits growth of g-pos bacteria.. this medium is ___-
Definition
selective
Term
s-s agar inhibits g-pos bacteria. on this medium is ______
Definition
both selective and differential
Term
a bacterial species that grows fastest at 55c, which means it is a ______
Definition
thermophile
Term
a _____ would be the most practical way to determine the number of bacteria in cottage cheese
Definition
plate cnt
Term
nitrogen will be found in proteins, which include ____
Definition
enzymes
Term
describe binary fission steps
Definition
after dna rep and cell elongation the membrane grow inward between the 2 new formed cells
Term
clostridium can be cultured in an anaerobic incubator or in the presence of atmospheric oxygen if thioglycolate is added to the nugrient broth the addition of thiog... makes the medium
Definition
reduced
Term
bacteria grown with a campypak that produces 5% co2 and 15% o2, this bacterium is a ____
Definition
microaerophile (atmosphere provided by the campypak has reduced lev of o2 perfect for microaerophile)
Term
bacteria that spoil food in the fridge are most likely _____, they prefer 20C
Definition
psychrotrophs
Term
if 52 bacterial colonies grow on agar inoculated with 1:1000 of hamburger hwo many bact originated
Definition
52,000