Lecture 2 Flashcards
Microscopy
How many lens does a simple microscope have?
1
objective lens x ocular lens =
total magnification
the ability of the lens to distinguish 2 points
resolution
what is the resolution of the best light microscope
0.2 micron
Shorter wavelengths of light provide
greater resolution
measure of the light bending ability of a medium
refractive index
What is used to keep light from bending?
immersion oil
What kind of background are dark objects visible against
bright ones
What backgrounds are light objects visible against?
dark ones
Accentuates diffraction of the light that passes through a specimen
phase-contrast microscopy
Accentuates diffraction of the light that passes through a specimen; uses two beams of light
differential interference contrast microscopy
Absorb UV light and emit visible light
Fluorescence microscopy
popularly used as a tag to illuminate living cells in a florescent microscope
GFP
Uses electrons instead of light
Electron microscopy
Produces a three-dimensional image
Confocal microscopy
Specimens may be stained with heavy metal sales
Transmission electron microscopy (TEM0
Ultrathin sections of specimen. The light passes through the specimen, then an electromagnetic lens to a screen or film
TEM
Produces a beam of electrons that scans the surface of a whole specimen.
Scanning electron microscopy (SEM)
Secondary electrons emitted from the specimen produce the image
SEM
Uses a metal and diamond probe inserted into the specimen and produces three dimensional image
Scanned probe- Atomic force microscopy
Coloring the microbe with a dye that emphasizes certain structures
staining
A thin film of solution of microbes on a slide
smear
the chromophore is a cation
in a basic dye
the chromophore is an anion
An acidic dye
staining the background instead of cells
negative staining
use of simple basic dye
simple stain
