lab exam 1- stains

52 terms by sflanigan 

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aseptic technique

transferring microorganisms from one location to the other without contamination

saccharomyces cerevisiae

bacteria used for wet mount

gram's iodine

stain used for wet mount

simple, selective, differential

types of staining

simple stain

involves use of a single stain which enables the microorganism to be more readily observed

selective staining

used to selectively stain specific bacterial structures which wouldn't be visualized in simple staining


allows distinction between different class of bacteria

positive simple stain

stains the organism

methylene blue

stain used in positive simple stain

bacillus subtillis, e coli

bacteria used for positive simple stain

negative simple stain

stains the background


stain used for negative simple stain

staphylococcus aureus

bacteria used for negative simple stain

malachite green, safranin

stains used for spore stain

both green

malachite green effects

spore-green, veg-colorless

water effects in spore stain

spore-green, veg-red

safranin effects in spore stain

bacillus subtilis

bacteria with spores in spore stain

cetylpyridinum chloride, congo red, methylene blue

stains used in cell wall stain

bacillus subtilis, staphylococcus aureus

bacteria used in cell wall stain

cell wall-red, inside cell-blue

results of cell wall stain

gram positive

thick cell wall, composed of 60-100% peptidoglycan

gram negative

chemically more complex cell wall, composed of less peptidoglycan and contains an exterior layer made of protein and lipopolysaccharides

crystal violet, gram's iodine, acetone-alcohol, safranin

stains used in gram stain

- will be colorless

effect of adding acetone alcohol to gram stain

- will be red

effect of adding safranin to gram stain


gram (?) will be purple throughout the gram stain process due to the binding of crystal violet

staphylococcus aureus

bacteria used in gram stain--> (+)

e coli

bacteria used in gram stain --> (-)

acid fast stain

some bacteria don't stain with gram stains, so they must use heat to drive the staining; retain their dye even when treated with acid

myobacterium tuberculosis and leprae

important acid fast pathogens

staphylococcus aureus, mycobacterium smegmatis

bacteria used for acid fast stain

carbolfuchsin, acid alcohol, methylene blue

stains used for acid fast stain

staphylococcus aureus

non acid fast

mycobacterium smegmatis

acid fast bacteria

can generate single colonies and good for maintaining cultures; broth + agar

solid media

usually maintained as a pure culture; useful for measuring growth kinetics; useful when looking at different stages of growth

liquid media

pure culture

culture with only a single species of microorganism growing in it

minimal media

chemically defined/synthetic media containing known compounds

complex media

nutrient rich media, but contains poorly defined extract (yeast, animal tissue)

enriched media

complex media + additional nutrients such as blood, serum


media that favors growth of one organism over the other

general purpose

media that grow a wide variety of microbes


media that exposes biochemical differences between two microbes

red colonies

ferment lactose, lower pH

white colonies

can't ferment lactose (MacConkey Medium)

1.5% agar

plates are solidified by adding this

92'C, 45'C

agar melts at ____ and solidifies at ____

121'C, 15 psi, 20 min

heat, P, T used in autoclave


all living cells, spores, viruses are destroyed on an object


killing or removal of disease-causing organisms from inanimate surfaces; surface not necessarily sterile


removing pathogens from teh surface of living tissue

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