Chapter 2 vocab mircobiology

negative stain

a stain that produces color around the structure of interest while not coloring the structure itself

Smear

a thin layer of a specimen on a slide

fluorescent

the ability of certain materials to absorb energy and then immediately release that energy in the form of light

atomic force microscope

a scanning probe microscope that uses a thin probe that is passed just above the specimen to measure forces between the atoms and the probe

immunofluorescence

a technique that uses a fluorescence microscope and antibody-specific fluorochromes to determine the presence of specific pathogens in a specimen

simple staining

a staining technique that uses a single dye

scanning probe microscope

microscope that uses a probe that travels across the surface of a specimen at a constant distance while the current, which is sensitive to the size of the gap, is measured

Phase-contrast microscope

a light microscope that uses an annular stop and annular plate to increase contrast

staining

the addition of stains or dyes to a microscopic specimen for the purpose of enhancing contrast

transmission electron microscope

a type of electron microscope that uses an electron beam, focused with magnets, that passes through a thin specimen

ultramicrotome

a device that cuts thin sections for electron microscopy

positive stain

a stain that colors the structure of interest

Ziehl-Neelsen technique

method of acid-fast staining that uses heat to infuse the primary stain, carbolfuchsin, into acid-fast cells

Endospore staining

a differential staining technique that uses two stains to make bacterial endospores appear distinct from the rest of the cell

scanning electron microscope

a type of electron microscope that bounces electrons off of the specimen, forming an image of the surface

counterstain

a secondary stain that adds contrasting color to cells from which the primary stain has been washed out by a decolorizing agent

Gram stain

a differential staining technique that distinguishes bacteria based upon their cell wall structure

flagella staining

a staining protocol that uses a mordant to coat the flagella with stain until they are thick enough to be seen

acidic dye

a chromophore with a negative charge that attaches to positively charged structures

darkfield microscope

a compound light microscope that produces a bright image on a dark background; typically a modified brightfield microscope

confocal microscope

a scanning laser microscope that uses fluorescent dyes and excitation lasers to create three-dimensional images

fixation

the process by which cells are killed and attached to a slide

differential staining

staining that uses multiple dyes to differentiate between structures or organisms

capsule staining

a negative staining technique that stains around a bacterial capsule while leaving the capsule clear

acid-fast stain

a stain that differentiates cells that have waxy mycolic acids in their gram-positive cell walls

Kinyoun technique

a method of acid-fast staining that does not use heat to infuse the primary stain, carbolfuchsin, into acid-fast cells

chromophores

pigments that absorb and reflect particular wavelengths of light (giving them a color)

brightfield microscope

a compound light microscope with two lenses; it produces a dark image on a bright background

fluorochromes

chromophores that fluoresce (absorb and then emit light)

electron microscope

a type of microscope that uses short-wavelength electron beams rather than light to increase magnification and resolution

basic dye

a chromophore with a positive charge that attaches to negatively charged structures

two-photon microscope

a microscope that uses long-wavelength or infrared light to fluoresce fluorochromes in the specimen

scanning tunneling microscope

a microscope that uses a probe that is passed just above the specimen as a constant voltage bias creates the potential for an electric current between the probe and the specimen

primary stain

refers, in differential staining techniques, to the first dye added to the specimen

phosphorescence

the ability of certain materials to absorb energy and then release that energy as light after a delay

mordant

a chemical added to a specimen that sets a stain

fluorescence microscope

a microscope that uses natural fluorochromes or fluorescent stains to increase contrast

decolorizing agent

a substance that removes a stain, usually from some parts of the specimen

Wet mount

a slide preparation technique in which a specimen is placed on the slide in a drop of liquid

Differential interference- contrast microscopes

a microscope that uses polarized light to increase contrast