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17 Cards in this Set
- Front
- Back
Microbes
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are tiny and measured in um( micrometers)
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1 um /1m
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= 10^-6 meters/ 3.38 ft 10^2 cm 10^3mm 10^6um 10^9nm 10^10 A
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Light Microscopy
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Visualize cellular specimens (EUK & PROK)
Use visible light to observe specimen total magnification 1000x- 2000x Resolution = 2 um |
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Bright field Microscope
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Most common
specimens dead and stained to contrast with medium look at light passing through specimen |
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Phase-Contrast Microscopy
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-Used to observe live specimen without stain
-look at light passing through and reflecting off specimen -good resolution |
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Differential Interference contrast DIC
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-Similar to phase contrast but used two light beams
-specimens appear 3D |
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Fluorescence Microscopy
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-Detects substances that absorb UV energy and emit visible light
-Specimen is stained with fluorescent dyes that tag specific features of the cell. |
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Confocal Microscopy
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computer controlled lasers illuminate one focal plane at a time through the whole depth of the specimen.
sliced into computer based 2d 3d images |
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Electron Microscopy
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visualize organelles and viruses
uses electron beams to visualize specimen total mag= 10,000- 100,000 x res- 2.5 um 2 types TEM / SEM |
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Transmission electron microscopy
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specimens must be cut into ultra thin sections view internal features
different parts of specimen absorb differing amounts of electrons resulting in black and white shades of gray density |
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Scanning electron Microscopy SEM
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Visualize molecules
uses probes traces surface topology total mag = almost infinite |
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scanned probe microscopy
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can visualize molecules
uses tiny probes to trace surface topology total mag= infinite total res 10^-12 |
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Positive Staining Basic Dyes
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Cations in dye attracted to negative cell surface.
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Negative staining acidic dyes
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anions repelled by most cells, adhere to glass slide instead of cell
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Simple stains
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single basic dye that stains whole cell
crystal violet |
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Differential Stains
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stain that reacts diff with diff types cells
distinguish one type of bacteria from another Acid fast stain |
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Special Stain
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stain specific feature of cell
Endospore stain |