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35 Cards in this Set
- Front
- Back
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The ability to make something appear larger by bending light waves.
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magnification
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The ability to distinguish two adjacent objects as separate.
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resolution
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The smallest distance required between points to distinguish them as separate.
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R= Resolving power
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NA stands for?
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Numerical Aperture
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R=?
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R=0.61λ/NA
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is a higher or lower resolving power number better?
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lower number is better
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4 steps to get the best resolution:
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1) blue light
2) condenser up 3) diaphragm adjusted for higher magnification 4) use oil w/ oil immersion objective |
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Type of microscopy where a specimen is on a slide, light comes up from underneath, passes through the specimen, goes up to the objective lenses, some of the light is absorbed by the specimen. Ends up with a DARK specimen on a WHITE background.
Value of this type? |
Bright-field microscopy
Value: true color |
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Type of microscopy that's pretty much the same as Bright-field microscopy but with an additional lens system: a STOP CONDENSER, which blocks direct light and only allows refracted light to pass. Ends up with a LIGHT specimen on a DARK background.
Value of this type? |
Dark-field microscopy
Value: motility studies. |
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Type of microscopy that magnifies changes in light density, resulting in high-contrast images. Allows viewing of intra-cellular structures.
Value of this type? |
Phase-Contrast microscopy
Value: living specimens |
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Type of microscopy that is used a lot in the medical field. Uses a UV radiation source and a dye causing sample to glow.
Value of this type? |
Fluorescence microscopy
Value: diagnosing infection |
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Type of microscopy that uses a beam of electrons moving in a wavelike pattern as energy source, instead of visible light.
Value of this type? |
Electron Microscopy
Value: electron waves are 100,000x shorter than visible light which provides tremendous Resolving Power. |
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two types of Electron Microscopes are?
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-Transmission Electron Microscope (TEM)
-Scanning Electron Microscope (SEM) |
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Type of electron microscope where laser sliced cross-sections are viewed.
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Transmission Electron Microscope
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Type of electron microscope that uses a coated sample to view contours or outside of the sample.
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Scanning Electron Microscope
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Do electron microscopes show color?
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never; they are black and white. Color is added to the images later.
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What are the ways of preparing a specimen? Values of each?
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-Wet Mounts or Hanging Drop Mounts
Value: live specimens; motility -disadvantage: temporary & hard to see -Fixed mount -Value: uses dyed smear; long lasting -disadvantage: they are dead. |
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What charge do most bacteria have?
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Negative charge
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What charge does Basic dye have?
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Positive charge
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What charge does Acidic dye have?
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Negative charge
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Describe Positive staining:
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Where a Basic (Positively) charged dye is used which, because of the (+) charge, adheres to the bacteria since they mostly (negatively) charged. This results in a DARK SPECIMEN on a light background.
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Describe Negative staining:
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Where an Acidic (Negatively) charged dye is used which repels (Negatively) charged bacteria and results in a LIGHT specimen on a DARK background.
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Stain that uses only one dye to stain an organism.
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Simple Stain.
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Stain that uses two different dyes to differentiate between cell types or cell parts.
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Differential Stain
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A stain used to emphasize a certain part or structure of the cell.
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Special Stain
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What are the only two parts built to support the weight of the microscope?
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arm & base
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The framework of the microscope consists of?
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the arm & base
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first lens is contained in?
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the condensor
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second lens is contained in?
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the nose piece; objective lenses
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the third set of lenses are?
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the ocular lenses
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how can you tell if dirt is on the ocular or objective lenses?
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rotate it; if it rotates it's the ocular. If it's stationary, it's the objective lens.
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Resolving power (R)=
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R=0.61λ/NA
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a circular glass disc that has a series of regularly spaced markings etched onto its upper surface.
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ocular micrometer
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a slide with markings etched upon it that are exactly 0.1mm and 0.01mm apart.
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stage micrometer
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What is the magnification range possible with electron microscopy?
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magnification between 5,000 x and 5,000,000x
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