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11 Cards in this Set

  • Front
  • Back
define Microscope
An optical system for magnification and illumination
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
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
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
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
Electron Microscopy ( 500000-1000000x)
-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
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
disadvantage of Electron Microscopy
-very expensive
-samples are dead killed always
-very lenghty sample preparation
-difficult to maintain the microscope
-no color
Wet mount sample or hanging drop
-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
Differential Staining
-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
Negative staining
-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