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
Contaminates are?
unknown or unwanted microbes in culture
what are some ways to identify a microbe?
cell and colony morphology or staining
DNS sequence
Biochemical testing
Immunological testing
What is a steak plate used for?
isolation
What is a pour plate used for?
isolation and numeration
what is a spread plate used for?
isolation and numeration
What are the three types of media?
Physical
chemical composition
functional type
what are three states of physical media?
Solid
semisolid
liquid
what % of Agar is in a solid media?
1.5%
what percent of agar is in a Semisolid media?
.35%
Hemolysis
cutting or breaking down of cells
Describe alpha hemolysis.
greening, partial lysis of Red Blood cell
describe Beta hemolysis
complete lysis of the red blood cell
describe gamma hemolysis
no lysis of the red blood cell
Describe Synthetic chemical Media.
contains pure organic and inorganic compounds in an exact chemical formula.
Describe Complex chemical media.
contains at least one ingredient that is not chemically definable
describe general Purpose media.
Grows a broad range of microbes, usually nonsynthetic
describe enriched chemical media
contains complex organic substances such as blood, serum, hemoglobin, or special growth factors required by fastidious microbes.
Nutrient Broth
Liquid medium containing beef extract and peptone
nutrient agar
solid media containing beef extract, peptone, and agar.
Selective Media
contains one or more agents that inhibit growth of some microbes and encourage growth of the desired microbes.
Differential Media
Allows growth of several types of microbes and displays visible differences among those microbes.
Reducing medium
contains a substance that absorbs oxygen or slows penetration of oxygen into medium; used for growing anaerobic bacteria.
Facultative Anaerobe
Doesn’t care if it has oxygen to grow or not.
carbohydrate Fermentation Medium
contains sugars that can be fermented, converted to acids, and a pH indicator to show this reaction.
Anaerobe
Doesn’t like oxygen to grow
Aerobic
Likes oxygen to grow.
Strict aerobe
Must have oxygen to grow
