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46 Cards in this Set
- Front
- Back
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phase contrast microscope
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allows visualization of unstained (LIVING) organisms; varoius cellular components have slightly different refractive indexes-->visible contrast among components as light passes through them
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compound light microscope
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tool to see living organisms too small to be seen with naked eye
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arm
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supports body; grasp when carryign microscope
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nosepiece
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rotating part where objective lenses attach
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objectives
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magnify images by power shown
low power=4X medium=10X high-dry=40X oil immersion=100X |
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ocular lenses
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"eyepieces"; magnify images by 10X
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total magnification
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objective x ocular
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body tube
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connects ocular lens to nosepiece (attached to objectives)
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mechanical stage
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supports microscope slide; allows slide to move in controlled fashion; hole in center to allow light to pass through to specimen
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condenser
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lens directly below microscope stage; concentrates light before it passes through specimen; adjust at high resolution
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iris diaphragm
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opening at bottom of condenser that regulates AMOUNT of light entering condenser; lever regulates size of opening; need more light at high resolution, but too much prevents contrast
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course adjustment focus
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moves body tube up/down to bring into initial focus; low and medium power only
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fine focus adjustment
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smaller knob within coarse focus; brings specimen into coarse focus(less distance per revolution); parfocal; use only after focus w previous objective
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resolving power
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ability of a lens to distinguish two nearby points as distinct and separate
-smaller resolving power=incr resolution -function of wavelength used and numerical aperture (N.A.) res.pow.= wavelength/2X N.A. -improved by shorter wavelength (UV)--but restricted to visible light -incr. resolution (decr resolving power) by incr numerical aperture |
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numerical aperture
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function of diameter of objective lens in relation to focal length and refractive index of medium between specimen and objective
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refractive index
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light bending power
-incr by oil in btw specimen and objective lens -RI of air < RI glass--> light bends as pass thru slide to air -RI oil=glass--> decr bending-->greater resolution-->smaller resolving power |
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Relationship between Objective Size, Working Distance and Diaphragm Position
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10X--greatest distance--mostly closed diaph.
40X--mid distance--partially open diaph. 100X--closest to specimen--completely open diaph. |
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negative stain
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INDIRECT stain; use acidic stain (nigrosin) w/ neg. charged chromagen-->stained BACKGROUND inst. of cells
advantages: stain air-dries inst. of heat fixed=no distortion; some bacteria do not absorb dyes |
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acid fast stain
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some bacteria require a different stain to interact w cell wall; these bacteria are NOT easily decolorized by acid-alcohol; use primary stain(carbol fuchsin), decolorizing agent (acid-alcohol), and counterstain (methylene blue)
-acid fast: do not decolorize, keep primary stain (red) -not acid fast: decolorize, then pick up counterstain (blue) ex. mycobacterium |
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spore stain
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ability to form metabolically inactive spore under adverse env. conditions
internal spores (endospore) accept primary stain (malachite green) rest of vegetative cell: primary stain rinses off with water, picks up counterstain (safranin)--red |
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capsule stain
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capsules external to cell wall protect bacteria from phagocytosis
capsule composed of polysaccharide or glycoprotein primary fuchsin stain: bacterial cell wall alcian blue counterstain: capsule --> pink bacterium surrounded by blue halo |
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aseptic technique
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methods used that prevent microorganisms from leaving tubes into ext. environment or microorganism from outside environment into sample (contamination); includes keeping tubes at angles, not creating drafts, heating inoculating tube, sterilizing tools
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gram stain
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type of differential stain; most widely used staining procedure in bacterioloy; divides into Gram negative and Gram positive by differences in cell wall
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Gram positive
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thick peptidoglycan cell wall
dehydrating effect of alcohol causes thick cell wall to shrink--holds in violet-iodine complex-->purple |
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Gram negative
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higher lipid content in outer membrane; less peptidoglycan
alcohol dissolves lipids in cell wall making membrane porous--crystal-violet complexes leak out, can pick up safranin stain-->pink/red |
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Stains
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1. crystal violet dye
2. Gram's iodine 3. alcohol (critical step) 4. safranin |
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screw-capped tubes
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need to be left ajar to allow for gas exchange (sugar or protein metabolism occur differently in absence of oxygen)
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streak plating
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streaking a suspension onto surface of agar plate; dilutes using 4 quadrants; produces well-separated colonies of bacteria from a mixed suspension (as exists in nature)
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inversion of agar plates
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avoids problems with condensation as incubates
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atmospheric oxygen requirements demonstration
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shake tubes with tryptone glucose yeast extract (TGYE) agra are inoculated with an organism while agar is molten
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capsule stain
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capsules external to cell wall protect bacteria from phagocytosis
capsule composed of polysaccharide or glycoprotein primary fuchsin stain: bacterial cell wall alcian blue counterstain: capsule --> pink bacterium surrounded by blue halo |
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aseptic technique
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methods used that prevent microorganisms from leaving tubes into ext. environment or microorganism from outside environment into sample (contamination); includes keeping tubes at angles, not creating drafts, heating inoculating tube, sterilizing tools
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gram stain
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type of differential stain; most widely used staining procedure in bacterioloy; divides into Gram negative and Gram positive by differences in cell wall
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Gram positive
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thick peptidoglycan cell wall
dehydrating effect of alcohol causes thick cell wall to shrink--holds in violet-iodine complex-->purple |
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Gram negative
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higher lipid content in outer membrane; less peptidoglycan
alcohol dissolves lipids in cell wall making membrane porous--crystal-violet complexes leak out, can pick up safranin stain-->pink/red |
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Stains
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1. crystal violet dye
2. Gram's iodine 3. alcohol (critical step) 4. safranin |
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screw-capped tubes
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need to be left ajar to allow for gas exchange (sugar or protein metabolism occur differently in absence of oxygen)
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streak plating
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streaking a suspension onto surface of agar plate; dilutes using 4 quadrants; produces well-separated colonies of bacteria from a mixed suspension (as exists in nature)
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inversion of agar plates
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avoids problems with condensation as incubates
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atmospheric oxygen requirements demonstration
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shake tubes with tryptone glucose yeast extract (TGYE) agra are inoculated with an organism while agar is molten
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anaerobic culture techniques demonstration
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organisms grown in 2 mediums: aerobically and anaerobically (Gas Pak system)
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Gas Pak system
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tightly sealed jar; water added to envelopes produce hydrogen and carbon dioxide; hydrogen released and oxygen present in jar react with catalyst at top of jar to make water-->feeds chemical production from envelopes; CO2 slowly replaces O2--white indicator when no O2 present
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oxidation-reduction potential
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ratio of oxygen to hydrogen of a cell
-aerobic cells: high -anaerobic cells: need low for enzymatic activity |
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aerobes
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need oxygen for growth
grow on top of shake tube present on aerobic medium absent in anaerobic medium |
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facultative anaerobes
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can grow with or without oxygen
grow on top of medium and within medium grow on both aerobic and anaerobic medium |
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anaerobe
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cannot grow in presence of oxygen
found at bottom of shake tube grow on anaerobic medium, not aerobic |
