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Microbiology Ch. 3


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copy deck
bending/change in the angle of the light rays as it passes into the lens
real image
intial specimen image formed by the objective
dfferential Interference Contrast (DIC)
detailed view of unstained, live specimens by manipulating light; adds contrasting color
gram positive
purple (primary stain); open faced cell wall structure
applying colored chemicals to identify
semisolid media
at room temp. clotlike consistancy; thickens but not firm
complex media
contains at least one ingredient that is not chemically defined (known) Ex. blood, serum, meat extracts, infusions, milk, yeast extract
enriched media
contains complex organic substances such as blood, serum, hemoglobin, or special growth factors (vitamins, AA)
solution containing nutrients for growth
selective media
contains one or more agents that inhibit the growth of a certain microbe(s) (A,B,C) , but not others(D) and thereby selects microbe D and allows it to grow
tiny sample of a species
Scanning Electron Microscope (SEM)
creates a 3-D view of anything; scans the specimen
contaminated culture
was pure or mixed, but now contains unknown organisms
transforms subtle changes in light waves passing through the specimen into light intensity differences
compound microscope
more than one lens, a lamp, and a condenser
unwanted microbes of uncertain identity
simple microscope
contains a single magnifying lens and a few working parts
special lens that converges/ focuses light rays to a single point
differential staining
to distinguish cell parts or types based on cell wall structure; more than one dye is used.Ex. Gram stain
colored chemicals
two types of disposal
steam sterilization (autoclave); incineration ( burning)
simple staining
requires only one dye
agar plate placed in a temperature controlled chamber or incubator to encourage growth
synthetic media
compositions are chemically defined; chemically known
pure culture
container growing only a single species
resolution (resolving power)
capacity of an optical system to distinguish two adjacent objects/ points as two points and not one blurred object
gently heated slide to adhere specimen to slide
liquid media
water based solutions that do not solidify at room temperatures above freezing and flow freely
mixed culture
container growing two or more indentified species
ocular lens
10x; eyepiece
petri plates
clear, flat, dish with a clear cover
virtual image
image received by the eye; formed by the ocular lens
differential media
grows several types of microbes and displays visible differences: colony size and color; media color changes; formation of gas bubbles and precipitation
Bright- field
most widely used; specimen will be dark and the area around it will be bright
sterile technique
inoculation starts with a sterile medium and sterile tools; prevents contamination
aggregation of cells; small; loose association of cells
total power of magnification
final image formed by the combined lenses (ocular & objective)
to make small objects large
ability to enlarge objects
the introduction of an inoculum into a nutrient medium
bacteria that require growth factors and complex nutrients
optical replica
streak plate method
small droplet of culture is spread, in a specific manner, over the surface of the medium
Dark- field
uses a stop to block all light from entering the objective except peripheral light that is reflected off the sides of the specimen
Inoculation, Incubation, Isolation, Inspection, and Identification
Five basic techniques to determine various species
objective lens
4x, 10x, 40x, 100x; closer to the specimen
resolving power (resolution)
show detail
gram negative
red (counterstain); closed sandwich cell wall structure
solid media
provides a firm surface; good for isolating and subculturing bacteria and fungi
UV radiation; dyes emit visible light when expose to shorter UV rays
a second-level culture; removing a tiny sample from one well isolated colony and transferring it into a seperate media container.
to cultivate microbes in an artifical environment
Transmission Electron Microscope (TEM)
transmits electrons through the specimen b/c electrons cannot penetrate thick preparations
spread on a thin film of cells & air- dry
general purpose media
designed to grow a broad spectrum of microbes

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