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60 Cards in this Set
- Front
- Back
Acid fast positive, such as tuberculosis, is colored
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red
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non acid fast is colored
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blue
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total magnification =
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objective lens x ocular lens
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resolution
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the ability of the lenses to distinguish between two points
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shorter wavelengths of light provide
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greater resolution
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refractive index
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a measure of the light-bending ability of a medium
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immersion oil is used to...
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keep light from bending
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brightfield illumination
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light reflected off the specimen does not enter the objective lens
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darkfield illumination
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light reflected off the specimen enters the objective lens
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phase-contrast microscopy
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accentuates diffraction o the light that passes through a specimen, good for viewing internal structures of unstained specimens
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differential interference contrast microscopy
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accentuates diffraction of the light that passes through a specimen, uses two beams of light
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flourescence microscopy
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uses UV light, fluorescent substances absorb UV light and emit visible light; cell may be stained with fluorescent dyes, useful to specifically id pathogens in specimens
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fluorochromes
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fluorescent dyes
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confocal microscopy
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can create a 3D image
cells tained with flurochrome dyes, the short wavelength (blue) light is used to excite the dyes, and the light illuminates each plane in a specimen to produce a 3D image up to 100 um deep |
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two-photon microscopy
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used to study cells attached to a surface; cells are stained with fluorochrome dyes; thwo photons of long-wavelength (red) light are used to excite the dyes;
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scanning acoustic microscopy
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used to study cells attached to a surface (such as a catheter tip); measures sound waves that are reflected back from an object
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electron microscopy
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uses electrons instead of light;
the shorter wavelength of electrons gives greater resolution |
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transmission electron microscopy (TEM)
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uses ultrathin section of specimen;
light passes through specimen, through an electromagnetic lens, to a screen or film; specimens may be stained with heavy metal salts |
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scanning electron microscopy (SEM)
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produces 3D images;
an electron gun produces a beam of electrons that scans the surface of a whole specimen; secondary electrons emitted from the specimen produce the image |
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scanning tunneling microscopy (STM)
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uses a metal probe to scan a specimen
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scanned-probe microscopy aka atomic force microscopy (AFM)
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uses a metal-and diamond probe inserted into the specimen to new 3D images
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staining
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coloring the microbe with a dye that emphasizes certain structures
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smear
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a thin film of a solution of microbes on a slide
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purpose of fixing a smear
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to attach the microbes to the slide and kill the microbes
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in a basic dye, the chromophore is a
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cation
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in an acidic dye, the chromophore is a
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anion
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negative staining
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staining the background instead of the cell
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simple stain
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use of a single basic dye
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mordant
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may be used to hold the stain or coat the specimen to enlarge it
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differential stains
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are used to distinguish between bacteria;
include the gram stain and acid-fast stains |
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gram positive bacteria tend to be killed by
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penicillin and detergents
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gram negative bacteria are more or less resistent to antibiotics
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more resistant
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why is gram negative more resistant to antibiotics?
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the cell wall has more lipids and is more water insoluble
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what is the #1 nosocomial infection
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E. coli
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gram stain primary stain
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crystal violent
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gram stain mordant
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iodine
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gram stain decolorizing agent
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alcohol-acetone
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gram stain counterstain
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safranin
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color of gram positive cells after safranin
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purple
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color of gram negative cells after safranin
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red
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myco-
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fungal
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what is different about an acid-fast cell
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the stained waxy cell wall is not decolorized bhy acid-alcohol
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what are two acid-fast cells
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Mycobacterium (TB)
Nocardia leprasy |
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acid-fast stain primary stain
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carbolfuchsin
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acid-fast stain decolorizing agent
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3% acid 97% alcohol
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acid-fast stain counterstain
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methylene blue
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color of acid-fast cell after methylene blue
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red
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color of non-acid-fast cell after methylene blue
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blue
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capsule staining
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negative stain and cells also stained; capsule appears as white halo around cell
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endospore stain primary stain
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malachite green, usually with heat
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endospore stain decolorizing agent
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water
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endospore stain counterstain
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safranin
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flagella staining uses
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mordant on flagella;
carbolfuchsin simple stain |
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a micrometer is equal to
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10-6 m or .000001 m
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a nanometer is equal to
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10-9 m
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first simple microscope
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by van Leeuwenhoek, single lens, 300x
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most ocular lens magnify by
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10x
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quorum sensing
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the ability of bacteria to communicate and coordinate behavior. bacteria that use quorum sensing produce and secrete a signaling chemical called an inducer
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example of a gram positive bacteria
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Staphylococcus epidermis
Bacillus subtilis |
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example of a gram negative bactera
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E. coli
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