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22 Cards in this Set
- Front
- Back
why do we use stains?
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to visualize bacteria
|
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steps of simple stain
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1) stain heat-fixed smear with methylene blue for 1 min
2) rinse with water 3) dry with bibulous paper 4) examine the slide microscopically under oil-immersion |
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Weose's 3 domains
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archae
bacteria eukarya |
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Graim stain
purpose |
to differentiate between Gram positive and Gram negative bacteria
|
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Gram negative
characteristics |
stain purple
thick peptidoglycan layer |
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Gram positive
characteristics |
stain pink
"sandwiched" peptidoglycan layer |
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steps of Gram stain
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1) Add crystal violet to heat-fixed smear. Stain 30 secs - 1 min. Rinse with water
2) Stain with iodine for 1 min. 3) Decolorize with 95% alcohol for 5-10 seconds. Rinse with water. 4) Stain with safranin for 30 secs - 1 min. Rinse with water. |
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Gram Stain
primary stain |
crystal violet
|
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Gram stain
mordant |
iodine
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Gram Stain
secondary stain |
safranin
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Gram Stain
decolorizer |
95% alcohol
|
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Christian Gram
|
Gram stain
|
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organisms used in Gram stain lab
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Bacillus megaterium
Escherichia coli Pseudomonas aeruginosa Stephylococcus aureus |
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Negative stain
purpose |
to demonstrate bacterial capsule
|
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Negative stain
stain used |
Nigrosin
(negatively charged) |
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Negative stain
steps |
1) Heat-fix the AIR dried nigrosin
2) Stain the smear with crystal violet for 1 minute 3) Rinse with water & view |
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Negative stain
primary stain |
Nigrosin
|
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Negative stain
secondary stain |
crystal violet
|
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Endospore Stain
purpose |
to detect endospores
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Endospore Stain
also known as |
Schaffer-Fulton
|
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Endospore stain
primary stain |
malachite green
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Endospore Stain
secondary stain |
safranin
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