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37 Cards in this Set
- Front
- Back
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Simple microscope
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microscope with one lens
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compound microscope
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microscope with multiple lenses
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light microscope
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use visible light to observe specimens, glass lens are used
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electron microscopy
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a beam of electron, instead of light is used to observe the specimens. Electromagnetic lens are used.
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resolution
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the ability to distinguish between two points
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compound light microscopy
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the shorter the wavelength used, the greater the resolution
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total magnification
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magnification of objective lenses X magnification of ocular lenses
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refractive index
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measure of light bending ability of the medium
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Changing the refractive index of specimens by staining -->
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increase the contrast between the specimen and the medium
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Mineral oil has the same refractive index as
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glass
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increase the diameter of objective lens -->
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increased resolution
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brightfield microscopy
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The field of vision is brightly illuminated. Useful for stained smears.
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darkfield microscopy
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darkfield condenser with opaque disc. Useful for unstained/extremely small organisms.
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phase-contract mircoscopy
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(compound light)
Condenser with annular (ring-shaped) diaphragm, and difraction plate in the objective lens. Useful for detailed observation of internal structure of stained or living organisms. |
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differential interference contrast (DIC) microscopy
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(compound light)
two beams of light and prisms. Allows for 3 dimensional observation of living cells. |
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fluorescence microscopy
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(compound light)
ultraviloet or near ultraviolet light and fluorescent-antibody (FA) technique. Useful for diagnostic applications. |
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confocal microscopy
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(compound light)
laser light, fluorochromes, and computer are used for 3-dimensional image of specimens |
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scanning acoustic microscopy (SAM)
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measures soundwaves that are reflected back from an object. Used to study cells attached to a surface.
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Electron microscopy
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A beam of electron, instead of light is used
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Transmission electron microscopy
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Useful for observing virus or internal structure of cells.
10,000-100,000x |
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Scanning electron microscopy
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Useful for observing surface features of cells or virus.
1000-10,000x |
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fixing the specimen on the slide
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kills microorganisms and attach them to the slide with minimal distortion
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acidic dye
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chromophore with negative ion
eg. eosin, acid fuchsin, India ink, and nigrosin |
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basic dye
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chromophore with positive ion
eg. crystal violet, methylene blue, malachite green, and safranin |
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mordant
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increase the affinity of the stain for a biological specimen, or coat the structure (eg flagella)
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simple stain
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using a basic dye to stain specimens, sometimes in conjunction with a mordant.
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Differential stains
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gram stain
acid fast stain |
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gram stain
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primary stain (crystal violet)
mordant (iodine) decolorizing agent (alcohol) counterstain (safranin) |
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gram-positive bacteria
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purple color
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gram-negative bacteria
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pink
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acid-fast stain
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primary stain (carbolfuchsin)
heat decolorizing agent (acid-alcohol) counterstain (methylene blue) |
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acid-fast bacteria
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red
eg. Mycobacterium species and Nocardia have waxy material (lipid-mycolic acids) in the cell wall. |
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Non-acid-fast
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blue
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Special stains
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capsule stain
endospore stain flagella stain |
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Capsule stain (negative staining)
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India ink or nigrosin for background stain and simple stain (eg. Safranin) for bacteria. Capsules appear as halos surrounding each bacteria.
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Endospore stain (Schaeffer-Fulton stain)
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primary stain (malachite green) with heat
wash with water counterstain (safranin) Endospore: green Vegetative cells: pink |
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Flagella stain
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mordant and carbofushcin to build up the diameter of flagella to be visible under the microscope.
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