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Why older pure cultures of gram positive organisms can appear red when gram stained?
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How does a stained smear of S epi and E coli made from 7-day-old cultures would appear?
A 7-day-old culture may appear gram negative, when the organmisms are actually gram positive. Thus, S. epi would appear gram negative, and E. coli gram negative.
Is Staphylococcus saprophyticus gram positive or negative?
Yes. Staphylococci are classified as gram positive bacteria and appear as purple spheres when Gram stained.
What are Donovan bodies?
Rod-shaped oval organisms found in tissue samples from patients with granuloma inguinale. Donovan bodies appear deep purple when stained with Wright's stain.
How does the cell wall aid in classifying bacteria?
Bacteria fall under 2 categories based on their cell wall, either Gram positive or Gram negative. The bacterial cell wall is composed of peptidoglycan. A special staining technique called Gram staining is used to differentiate between these bacteria. Gram positive bacteria, containing a thick layer of peptidoglycan, will retain/absorb more of the crystal violet dye and appear purple/blueish after being stained. Gram negative bacteria contain an outer membrane which Gram positive bacteria do not. Also the peptidoglycan layer is much thinner compared to that of a Gram positive bacteria. This thinner layer will not absorb as much of the crystal violet dye as compared to the Gram positive bacteria. When a counterstain is added, the Gram negative bacteria will appear reddish/pinkish. Cliff notes Bacteria classified as either - Gram Positive -Gram Negative Gram Positive - No outer membrane - Thick layer of peptidoglycan - Will appear purple when stained Gram negative - Contain an outer membrane - Thin layer of peptidoglycan - Will appear reddish/pink when stained
What type of succession are pioneer organisms involved?
they are the last organisms to appear.
What color are gram-negative organisms if you over-decolorized them?
If the Gram Stain is completed properly, gram positive should stain purple; however, if you over decolorize a gram positive organism, the organism will appear appear pink, which is a gram negative reaction. To summarize, if you over decolorize a gram positive organism it will show as a gram negative organism.
What different cultures are in Paris?
there are a few which it won't appear in my head
One innovation that all foraging cultures appear to have lacked?
writing.
Does Poseidon appear in other cultures?
Yes. He appears in Roman mythology as Neptune.
What would be the result of over destaining on gram-positive types?
Over destaining can cause the purple color from the gram positive bacteria to be washed away, so when you apply the safrinin the gram positive bacteria will take up a pink color causing gram positive bacteria to appear gram negative.
What organisms are thought to have been the first to appear on earth?
bacteria
When treated with Gram stain Gram-positive bacteria appear?
Gram positive bacteria retain the violet stain, and appear purplish under a microscope.
