Chapter 3 Flashcards
The shorter the wavelength used
The greater the magnification
A measure of the light bending ability of a medium
Refractive index
Compound light microscope produces
Brightfield illumination
Used to see live organisms, produces a dark background
Darkfield microscopy
Used to see the internal structure of live cells, shades of gray to black
Phase contrast microscopy
Uses two beams of light, bright colors and appears 3-d
Differential interference microscopy
Takes advantage of fluorescence (the ability of a substance to absorb short wavelengths of light), uses florochromes, bright object against a black background
Fluorescence microscopy
Uses antibodies (natural defense molecules that are produced by humans and many animals In Reaction to a foreign substance or antibody) which combine with a fluorochrome
Immuno fluorescence
Used to reconstruct a 3-d image, used with computers
Confocal microscopy
2 photons, red light, used to excite a chlorophore, depth of 1000 mg
Two photon microscopy
Living cells, sound wave interpretation
Scanning acoustic microscopy
Ability of lenses to distinguish between two points that are a specified distance apart
Resolution
Finely focused beam of electrons from an electron gun passes through a specially prepared ultra thin section of a specimen, viruses or cell structures
Transmission electron microscope
Primary electrons sweep across the specimen and knock electrons from it’s surface
Scanning electron microscope
Structures that appear as a result of the preparation method
Artifacts
Tungsten probe, can resolve features that are only 1/100 the size of an atom
Scanning tunneling microscope
Metal and diamond probe, forced down on specimen, produces 3-d image
Atomic force
Cation
Basic dyes
Anion
Acidic dyes
Coloring the Microorganisms with a dye that emphasizes certain structures
Staining
Salts composed of a positive and negative ion one ion is colored and known as the chromophore (basic dyes: cation, acidic dyes: anion). Bacteria are negatively charged so cations are attracted
Stains
Cystal violet, methylene blue, malachite green, Safarinin
Basic dyes
Colors stain the background
acidic dyes
Aqueous or alcohol solution of a single basic dyed
Simple stains