Microbiology: Tools of the Laboratory Chapter 3 Flashcards
Magnification
ability to enlarge objects
Resolving Power
ability to show detail
Total magnification
of the final image is a product of the separate magnifying powers of the two lenses.
Bight-Field
most wisely used; specimen is darker than surrounding field; used for live and preserved stained specimens.
Dark-Field
Brightly illuminated specimens surrounded by dark field; used for live and unstained specimens.
The ability to distinguish between two separate adjacent objects is
resolution
Phase-Contrast
transforms subtle changes in light waves passing through the specimen into differences in light intensity, best for observing intracellular structures.
Transmission Electron Microscope
Transmit electron through the specimen. Darker areas represent thicker, denser parts and lighter areas indicate more transparent, less dense parts.
Scanning Electron Microscope
Provide details three-dimensional view. SEM bombards surface of a whole, metal-coated specimen with electrons while scanning back and forth over it.
Wet Mounts
allow examination of characteristics of live cells: size, motility, shape, and arrangement.
Fixed Mounts
are made by drying and heating a film of specimen.
Basic Dyes
Cationic, positively charged chromophere.
Such as; Methylene blue, brilliant green, and Safranin
Positive Staining
Surfaces of microbes are negatively charged and attract basic dyes
Acidic Dyes
Anionic, negatively charges chromophore.
Negative Staining
microbe repels dye, the dye stains the background.
Simple Stains
One dye is used; reveals shape, size, and arrangement.
Differential Stains
use a primary stain and a counterstain to distinguish cell types or parts.
Such as; gram stain, acid-fast stain, and endospore stain.
Structural Stains
Reveal certain cell parts not revealed by conventional methods: capsule and flagellar stains.
What microscope is capable of getting an image of a Rotavirus?
Transmission Electron microscope.
What are the 6 I’s of Culturing Microbes?
inoculation isolation incubation inspection information gathering identification
what does a Colony consist of?
one species
What are three isolation techniques?
streak plate
pour plate
Spread plate
Pure culture means?
a single species growing in a container
Mixed culture means?
Multiple species growing in a container
