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11 Cards in this Set
- Front
- Back
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define Microscope
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An optical system for magnification and illumination
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Light Microscopy (1000x2000x)
--Brightfeild microscope |
-used everyday in labs
-drk object on light background -2 lens system(objective and ocular ) -Illumination-articifial light source has a condenser lens -resolving power-wave length of light --- the smaller the better resolution -usually stained and dead , which causes distortion -if the MO is alive it the light has to be reduced to see the MO |
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Light Microscopy (1000x2000x)
--Dark feild Microscopy |
--differs from brightfeild in that there is a special condenser that directs light away from the objective and only light that has struck the seample is reflected back to the objective and visible.
--sample is living and unstained |
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Light Microscopy (1000x2000x)
Flouresence Microscopy |
specimen has been stained with a flouresent stain, this gives off visible light when bombbarded with UV light
--flouresent dyes can be atteced to antibodies to view specific species USED TO IDENTIFY SPECIFIC SPECIES |
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Light Microscopy (1000x2000x)
Phase contrast microscopy and interface microscopy |
permit contrast to be observed in diffrent parts of the cell without the use of dyes or stains
--diffrent parts of the cell have diffrent indexes and this allows diffrent shades of gray for diffretn parts of the cell --used to view living and unstained specimens GREAT for cilia, flagella and intercellualr oragnisms |
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Electron Microscopy ( 500000-1000000x)
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-electron beams have much shorter wave lengths than light visible light , This greatly improves reseolution
-lenses are made of magnets -image viewed on a monitor |
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Electron Microscopy ( 500000-1000000x)
Name 2 types |
TEM - transmission electron Microscopy
have very thin slices of samples that the electron beam passes thru SEM-scanning electron microsope- coat the surface of the sample with platinum and the beams bounce off the sample instead of thru it, great 3D effect |
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disadvantage of Electron Microscopy
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-very expensive
-samples are dead killed always -very lenghty sample preparation -difficult to maintain the microscope -no color |
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Wet mount sample or hanging drop
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-Best for viewing living organisms
-also good for viewing structures that otherwise would change when being stained -best if used with brightfeild microscopy or dark feild microscopy -remember to decrese the light of using brightfeild microscopy |
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Differential Staining
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-dried fixed and stained smears of specimens
-dried, speread specimen on slide and let air dry -fixed- heat fix by passin g thru the flame 2 or 3 times - causes distorion-shrimkage and change in shape -used to identify parts of cells ex spores or flagella Look at handout for examples |
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Negative staining
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-apperance similar to dark feild microscopy
-good for capsule stains -use india ink or nigrosin -no heat fixing thus less distortion -similar to darkfeild we see the specimen at lighter spots -no shrinkage |
