Microbiology Ch 3 - Harman
A nanometer (nm) = _____________ m
.000000001 m (10^-9)
A micrometer = __________ m
.000001 m (10^-6)
1 meter (m) = ____ decimeters (dm), ____ centimeters (cm), or _____ millimeters (mm)
1 m = 10 dm, 100 cm, 1000 mm
micro =
1/1,000,000
nano (nm) =
1/1,000,000,000
pico (pm) =
1/1,000,000,000,000
deci (dm) =
1/10
centi (cm) =
1/1000
Units in the metric system relate to each other by factors of ___
10
What is the typical magnification of the ocular lens?
10
kilo (km) =
1000
Which objective lens do you use for oil immersion?
100X
What are the typical magnification powers of the objective lenses?
10X, 40X, and 100X
What is the resolution of a TEM?
2.5 nm
What is the resolution of a SEM?
20 nm
Differential stain that binds strongly only to bacteria that have a waxy material in their cell walls
Acid-fast stain
Which ion is the chromophore in acidic dyes?
Anion (negative)
Natural defense molecules that are produced by humans and many animals in reaction to a foreign substance (antigen)
Antibodies
Structures that appear as a result of the preparation method
Artifacts
Microscopy that uses a metal-and-diamond probe to gently put force on a specimen; as the probe moves,, its movements are recorded in a 3 dimensional image
Atomic Force microscopy (ATM)
What color are all electron microscope observations?
Black and white (unless colored artificially)
By focusing light, what does the condenser produce?
Brightfield illumination
How do you change the refractive index, and what is its purpose?
By staining, so that there is a sharp contrast to its medium
What is the simple stain that is "layered" on the flagellum?
Carbolfuchsin
Which ion is the chromophore in basic dyes?
Cation (positive)
Microscope with a series of lenses and uses visible light as its source of illumination
Compound light microscope
The part of the microscope that has lenses that direct the light rays through the specimen
Condensor
A technique in light microscopy used to reconstruct three-dimensional images--specimens stained with fluorochromes--uses a pinhole aperture
Confocal Microscopy
Stain that is a contrast to the primary stain
Counterstains
Used to examine live microorganisms that either are invisible in the ordinary light microscope, cannot be stained by standard methods, or are so distorted by staining that heir characteristics are obscured
Dark field microscopy
Microscopy that uses differences in refractive indexes, but uses two beams of light instead of one
Differential interference contrast microscopy (DIC)
Stain that uses two different colored dyes
Differential stain
The scattering of light rays as they 'touch' a specimen's edge
Diffraction
In acidic dyes, what does the dye bind to?
Does not bind to specimen, but around it
What kind of lens does an electron microscope use?
Electromagnetic lenses
Microscopy that can observe objects smaller than 2 micrometers such as viruses or the internal structures of cells
Electron Microscope
Process that kills the microorganisms while simultaneously fixes them to the slide
Fixing (fixed)
Microscopy that takes advantage of fluorescence, by staining with a fluorescent dye called fluorochromes and examined with an ultra-violet light source
Fluorescence Microscopy
The principle use of fluorescence microscopy that is a diagnostic technique
Fluorescent-antibody (FA) technique or Immunofluorescence
Differential stain that classifies bacteria into gram-positive or gram-negative
Gram stain
What are two types of differential stains?
Gram stain Acid-fast
Which gram-stain charge means that bacteria are more resistant to antibiotics?
Gram-negative
Which gram-stain charge tends to be killed by penicillin and detergents?
Gram-positive
What is the advantage of the TEM?
High resolution and is extremely valuable for examining different layers of specimens
The light source of a microscope
Illuminator
What is done to preserve the direction of light rays at the highest magnification through a stain?
Immersion oil
Because of the flagella size, what cannot be used for observing them?
Light microscope
The use of any kind of microscope that uses visible light to observe specimens
Light microscopy
What is the primary stain for endospore staining?
Malachite green, usually with heat
What are scanned-probe microscopes used for?
Map atomic and molecular shapes, characterize magnetic and chemical properties, and to determine temperature variations inside cells
What measuring system is used for measuring microorganisms?
Metric system
A chemical added to a solution to intensify the stain
Mordant
What is applied to the flagella for staining?
Mordant
How do you calculate the total magnification of a specimen?
Multiplying the objective lens magnification by the ocular lens magnification
What is a species that Acid-fast stains work on?
Mycobacterium species and Nocardia sp.
What is the substance found in the acid-fast bacterial cell wall that makes it a waxy substance?
Mycolic acid
What is used for special staining a capsule?
Negative stain (nigrosine or India ink) Stained with safranin
Preparing a colorless bacteria against a colored background
Negative staining
Light rays on the microscope pass into this lens, which is closest to the specimen
Objective lens
The part of the microscope that magnifies the image of the specimen (eyepiece)
Ocular lens
What are the disadvantages of the TEM?
Only a thin section can be examined, and has no three-dimensional aspects Are fixed and dehydrated, therefore the specimen is killed, and could be shrunk or distorted
Microscopy when one set of light rays comes directly from the light source, and the other set comes from light that is reflected or diffracted from a particular structure in the specimen
Phase-Contrast Microscopy
A measure of the light-bending ability of a medium
Refractive index
The 'resolving power'; the ability of the lenses to distinguish fine detail and structure
Resolution
What is used to counterstain for endospores?
Safranin
What makes up a stain?
Salts made of a positive ions and negative ion
Microscopy using various kinds of probes to examine the surface of a specimen using electric current, which does not modify the specimen
Scanned-probe microscopy
Electron microscope that provides a three-dimensional view of specimens-an electron gun produces a finely focused beam of electrons that pass through electromagnetic lenses and are directed over the surface of the specimen
Scanning Electron Microscopy (SEM)
What are two types of scanned-probe microscopes?
Scanning Tunneling microscopy Atomic Force Microscopy
Microscopy that consists of interpreting the action of a sound wave sent through a specimen--used to study living cells attached to another surface
Scanning acoustic microscopy (SAM)
Microscopy that uses a thin tungsten probe that scans a specimen and produces an image that reveals the bumps and depressions of the atoms on the surface of the specimen
Scanning tunneling microscopy (STM)
An aqueous or alcohol solution of a single basic dye
Simple
The thin film of material containing the microorganisms that is spread over the surface of the slide
Smear
What kind of stain is used to distinguish parts of the cell such as endospores, flagella, or capsules?
Special stains
Coloring the microorganisms with a dye that emphasizes certain structures
Staining
In basic dyes, what does the dye bind to?
The specimen
Electron microscope that has finely focused beam of electrons from an electron gun and passes through a specially prepared, ultra thin section of the specimen
Transmission electron microscope
What are the two types of electron microscopes?
Transmission electron microscope Scanning electron microscope
Usese a fluorochrome stain, and uses long-wavelength (red) light, using two photons instead of one
Two-photon microscopy (TPM)
What can you examine with a compound light microscope?
Very small specimens as well as some of their fine detail
What is used to decolorize an endospore?
Water
How is the Phase-Contrast method useful?
When observing internal structures of a cell, they become more sharply defined, permitting detailed examination
The ion in a stain that is colored
chromophore
