question

The ability of microbes to utilize N2, as a nitrogen source is called....

answer

nitrogen fixation

question

bacterial growth refers to an increase in the ____ of bacterial cells

answer

number

question

an unknown organism grows at the top of a tube of thioglycolate broth.. This organism is _____ for oxygen requirements

answer

aerobe

question

salt agar tends to inhibit the growth of most organisms except staph. this is an example of _____ media

answer

selective

question

this method , cells are added to melted agar, and poured into a dish

answer

pour plate method

question

bacteria reequire nitrogen for the synthesis of

answer

proteins

question

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

answer

bacteria are most likely growing in biofilms...

question

an organism that grows both in the presence and the absence of o2 and uses oxygen when it is avail

answer

facultative anaerobe

question

culture medium consisting of agar, peptone, and beef heart extract..

answer

complex medium

question

niacin, when added to a medium would be considered

answer

organic growth factor

question

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

answer

radioactive carbon dioxide (conversion of c as glucose to c as co2 indicates the metabolism...thus life

question

a medium containing lauryl sulfate inhibits growth of g-pos bacteria.. theis medium is

answer

selective,

question

a medium that inhibits the growth of certain bacteria while permitting the growth of others is described as

answer

selective

question

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

answer

complex medium

question

if there is not a formula for crude oil, the medium would be described as

answer

complex medium

question

what is the third step in binary fission

answer

inward growth of membrane

question

which biosafety leve, has ... open lab benchtop, gloves, lab coat, and face prtotection

answer

2

question

psychrotrophic org are often responsible for food spoilage in refrigerated foods, t or f

answer

true

question

t or f... adding salts to a solution increases osmotic pressure and is used to preserve food

answer

true

question

microaerophiles do not require oxygen for growth t or f

answer

false

question

aerotolerant organisms can grow in the presence of oxygen because their cell wall protects them from toxic prod of oxygen... t or f

answer

false

question

microaerophiles do not require oxygen for growth

answer

false

question

in a direct microscopic cnt, dead cells are easily differenctiated from live cells t or f

answer

false

question

why is homemade potato salad refig overnight and served without any cooling on a warm day bad?

answer

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.

question

what is the disadvantage of using turbidity to estimate the number of viable bact cells in a broth

answer

turbidity method counts dead celss as well as those that are viable and turbidity cannot be used on very dilute population

question

slower growing bact would have a ____ slope than those with a faster generation time

answer

greater slope (therefore; faster-growing bacteria would have a greateater slope than would those with a slw gen time

question

t or f, psychrotrophic org are often responsible for food spoilage in refrigerator

answer

true

question

adding salts to a solution increases the osmotic press and is used as a preservative t or f

answer

true

question

microaerophiles do not require oxygen for growth

answer

false

question

aerotolerant org can grow in a the presence of oxygen because their cell wall protects them from toxic products of oxygen

answer

false

question

during the stationary phase, bacteria cont to undergo binary fission

answer

true

question

candle jars work well for cultivating anaerobic bacteria t or f

answer

false

question

when the spread plate tech is used to inoculate culture media some colonies form within the agar- t or f

answer

false

question

in a direct microscopic cnt, dead cells are easily diff from live t or f

answer

false

question

turbidity or cloudiness of a cell culture measured by spectophotometry is useful in detecting sm amt of microbial contamination in liq t or f

answer

false

question

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

answer

true

question

shrinking of the cells cytoplasm in response to osmotic loss is called

answer

plasmolysis

question

the enzyme ___ catalyzes the conversion of peroxide to water and oxygen...

answer

catalase

question

the ___ is the most common tech used to obtain pure cultures of microbes (3 words)

answer

streak plate method

question

bacterial growth refers to an increase in the _____

answer

number of bacterial cells

question

an unknown org grows at the top of a tube of thioglycolate broth, the org is best described as..... for oxygen req

answer

aerobe

question

salt agar tends to inhibit the growth of most organisms except staph.. this is ____ media

answer

selective media

question

in a ____ cells are added to melted agar

answer

pour plate

question

a type of cell to cell communication that allows bact growing in biofilms to communicate and coordinate their activity is known as ____

answer

quorum sensing

question

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

answer

3200

question

infections concerd with biofilms ... the bacteria in biofilms are more likely to be __________

answer

resistant to antibiotics

question

what tech will allow you to get isolated colonies on agar

answer

useing a streak plate technique to inocultae

question

a medium containing lauryl sulfate inhibits growth of g-pos bacteria.. this medium is ___-

answer

selective

question

s-s agar inhibits g-pos bacteria. on this medium is ______

answer

both selective and differential

question

a bacterial species that grows fastest at 55c, which means it is a ______

answer

thermophile

question

a _____ would be the most practical way to determine the number of bacteria in cottage cheese

answer

plate cnt

question

nitrogen will be found in proteins, which include ____

answer

enzymes

question

describe binary fission steps

answer

after dna rep and cell elongation the membrane grow inward between the 2 new formed cells

question

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

answer

reduced

question

bacteria grown with a campypak that produces 5% co2 and 15% o2, this bacterium is a ____

answer

microaerophile (atmosphere provided by the campypak has reduced lev of o2 perfect for microaerophile)

question

bacteria that spoil food in the fridge are most likely _____, they prefer 20C

answer

psychrotrophs

question

if 52 bacterial colonies grow on agar inoculated with 1:1000 of hamburger hwo many bact originated

answer

52,000

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