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63 Cards in this Set
- Front
- Back
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cationic dye
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(also called basic dye) an ionic compound, used for staining bacteria, in which the positive ion imparts the color
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resolving power
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a numerical measure of the resolution of an optical instrument
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wet mount
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microscopy technique in which a drop of fluid containing the organisms (often living) is placed on a slide
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microscopy
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the technology for making very small things visible to the unaided eye
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compound light microscope
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a light microscope with more than one lens
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body tube
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microscope part that conveys an image from the objective to the eyepiece
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diffraction
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Phenomenon in which light waves, as they pass through a small opening, are broken up into bands of different wavelengths
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immersion oil
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substance used to avoid refraction at a glass-air interface when examining objects through a microscope
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flourescent antibody staining
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procedure in flourescence microscopy that uses a flourochrome attached to antibodies to detect the presence of an antigen
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iris diaphragm
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adjustable device in a microscope that controls the amount of light passing through the specimen
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binocular
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referring to a light microscope having two eyepieces (oculars)
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fine adjustment
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focusing mechanism of a microscope that very slowly changes the distance between the objective lens and the specimen
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electron micrograph
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a "photograph" of an image taken with an electron microscope
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stain
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(also called dye) a molecule that can bind to a structure and give it color
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dark-field illumination
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in light microscopy, the light that is reflected from an object rather than passing through it, resulting in a bright image on a dark background
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flagellar staining
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a technique for observing flagella by coating the surfaces of flagella with a dye or a metal such as silver
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mechanical stage
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attachment to a microsope stage that holds the slide and allows precise control in moving the slide
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light microscopy
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the use of any type of microscope that uses visible light to make specimens observable
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scanning tunneling microscope (STM)
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also called scanning probe microscope; type of microscope in which electrons tunnel into each other's clouds, can show individual molecules, live specimens, and work underwater
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luminescence
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process in which absorbed light rays are reemitted at longer wavelengths
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flourescence microscopy
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use of ultraviolet light in a microscope to excite molecules so that they release light of different colors
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condenser
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device in a microscope that converges light beams so that they will pass through the specimen
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freeze-etching
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technique in which water is evaporated under vacuum from the freeze-fractured surface of a specimen before the observation with electron microscopy
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phosphorescence
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continued emission of light by an object when light rays no longer strike it
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resolution
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the ability of an optical device to show two items as separate and discrete entities rather than a fuzzily overlapped image
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transmission
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the passage of light through an object
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Schaeffer-Fulton spore stain
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a differential stain used to make endospores more visible
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active site
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area on the surfaceof an enzyme to which its substrate binds
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atomic force microscope (AFM)
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advanced member of the family of scanning tunneling microscopes, allowing 3-dimensional views of structures from atomic size to about 1mm
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ocular micrometer
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a glass disk with an inscribed scale that is placed inside the eyepiece of a microscope; used to measure the actual size of an object being viewed
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shadow casting
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the coating of electron microscopy specimens with a heavy metal, such as gold or palladium, to create a three-dimensional effect
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differential stain
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use of two or more dyes to differentiate among bacterial species or to distinguish various structures of an organism; for example, the Gram stain
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objective lens
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lens in a microscope closest to the specimen that creates an enlarged image of the object viewed
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micrometer
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(mm) unit of measure to 10^-6m; formerly called a micron (m)
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refraction
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the bending of light as it passes from one medium to another medium of different density
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scanning electron microscope (SEM)
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type of electron microscope used to study the surface of specimens
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absorption
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process in which light rays are neither passed through nor reflected off an object but are retained and either transformed to another form of energy or used in biological processes
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total magnification
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obtained by multiplying the magnifying power of the objective lens by the magnifying power of the ocular lens
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simple stain
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a single dye used to reveal basic cell shapes and arrangement
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bright-field illumination
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illumination produced by the passage of visible light through the condenser of a light microscope
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anionic dye
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(also called acidic dye) an ionic compound, used for staining bacteria, in which the negative ion imparts the color
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transmission electron microscope (TEM)
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type of electron microscope used to study internal structures of cells; very thin slices of specimens are used
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numerical aperture
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the widest cone of light that can enter a lens
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electron microscope
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microscope that uses a beam of electrons rather than a beam of light and electromagnets instead of glass lenses to produce an image
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Angstrom (A)
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unit of measurement equal to 10210m - no longer officially recognized
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index of refraction
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a measure of the amount that light rays bend when passing from one medium to another
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parfocal
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for a microscope, remaining in approximate focus when minor focus adjustments are made
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monocular
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refers to a light microscope having one eyepiece (ocular)
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flouresce
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emission of light of one color when irradiated with another, shorter wavelength of light
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freeze-fracturing
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technique in which a cell is first frozen and then broken with a knife so that the fracture reveals structures inside the cell when observed by electron microscopy
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phase-contrast microscopy
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use of microscope having a condenser that accentuates small differences in the refractive index of various structures within the cell
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reflection
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the bouncing of light off an object
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negative staining
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technique of staining the background around a specimen, leaving the specimen clear and unstained
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Ziehl-Neelsen acid-fast stain
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a differential stain for organisms that are not decolorized by acid in alcohol, such as the bacteria that causes Hansen's disease (leprosy) and tuberculosis
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heat fixation
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technique in which air-dried smears are passed through an open flame so that organisms are killed, adhere better to the slide, and take up dye more easily
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smear
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a thin layer of liquid specimen spread out on a microscope slide
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hanging drop
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a special type of wet mount often used with dark-field illumination to study motility of organisms
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ocular lens
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lens in the microscope that further magnifies the image created by the objective lens
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Nomarski microscopy
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differential interference contrast microscopy; utilizes differences in refractive index to visualize structures, producing a nearly three dimensional image
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nanometer
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(nm) unit of measure equal to 10^-9m; formerly called a millimicron (mm)
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Gram stain
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a differential stain that uses crystal violet, iodine, alcohol, and safranin to differentiate bacteria. Gram-positive bacteria stain dark purple; Gram-negative ones stain pink/red
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coarse adjustment
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focusing mechanism of a microscope that rapidly changes the distance between the objective lens and the specimen
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mordant
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a chemical that helps a stain adhere to the cell or cell structure
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