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29 Cards in this Set
- Front
- Back
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How do you calculate total magnification
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ocular lens power x objective lens power
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What magnification do we use for focusing organisms?
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the scanning power objective lens (4x)
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Why is immersion oil used?
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to increase the clarity of the objects being viewed on the slide
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What is resolution
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the ability to discern objects from one another
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What are the different components of a microscope
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oculars
nosepiece objectives arm stage diaphram coarse adjustment knob fine adjustment knob condenser base |
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How do we clean a microscope?
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with lens paper
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How should the microscope be set when put away?
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Lowest power, stage lowered all the way, condenser set at 4x, ocular lenses reversed, plastic covering over microscope
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Where are organisms found
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everywhere, they are ubiquitous
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How do we describe colonies?
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three descriptions of an individual colony including
color shape margin elevation size appearance |
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How do we describe liquid growth
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with turbidity (cloudiness)
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If a plate has no colonies, how is the result written? 350 colonies? regular number range?
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<1 CFU
TNTC regular number range is 1-250 |
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Where are plates and tubes incubated? How are the plates oriented?
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in either test tube racks or agar racks. agar plates are oriented agar down to avoid pooling of moisture on agar surface.
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What is aseptic technique?
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technique to avoid contamination of unwanted microbes
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How do we perform aseptic technique in the lab?
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goggles, handwashing, labcoat, flaming tools, sterilization, etc
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How do you determine if a culture is pure?
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If it only contains one type of organism
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What should a pure culture look like?
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isolated and separated individual colonies
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How could you confirm that a culture is pure?
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perform a streak plate to dilute the organisms concentration and create isolated and separated individual colonies
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What stain do you use for negative staining?
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Nigrosine because it has a negative charge
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Why did the organism stain this way?
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because organisms have a negative charge, and the Nigrosine stain has a negative charge, they will repel and the coloration will only affix itself around the cell of the organism
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What type of organism was negatively stained that has culturing issues?
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tooth plaque has spirochetes
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Was heat involved in staining the negatively stained culture? Why or why not?
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HELP
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How do you perform a broth smear?
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add one loopful of the broth and transfer it to the center of the slide
create a thin film of mixture on the slide air dry heat fix stain view |
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How do you perform an agar smear?
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Add a loopful of water to a slide
Use the needle to transfer a small amount of the organism from the agar into the drop of water on the slide. Mix them together to form a thin layer Air dry Heat Fix Stain View |
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Name the simple stains
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Carbolfuschian
Methelene Blue Safranin Crystal Violet |
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Why do we stain organisms?
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in order to see the cell shape and arrangement of the cells
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What does the simple staining of the organism tell us?
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Whether or not the cell is gram negative or gram positive, based off of which stain adhered to which organism.
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Why do we heat fix?
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In order to adhere the cells to the glass of the slide
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Does the organism need to be dry on the slide prior to heat fixing?
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Yes, otherwise the premature heat fixing could cause cell distortions or not properly adhere to the slide
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What do we dry the slide with?
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Air
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