2: Observing Microorganisms Through a Microscope Flashcards
diameter of most bacteria
0.2 to 2.0 micrometers
diameter of typical human RBC
7 micrometers
spiral-shaped bacterium that is the leading cause of stomach ulcers, chronic inflammation, and resulting stomach cancer
helicobacter pylori
magnification of objectives lenses
low power=10X; high dry=40X; oil immersion=100X
magnification of ocular lens
10X
ability of the lenses of a microscope to distinguish between two separate points a specified distance apart
resolution
Light microscopes cannot resolve structures smaller than____
0.2 micrometers
a measure of the light-bending ability of a medium
refractive index
how does staining bacteria help them be more easily seen?
changes their refractive index relative to the surrounding material
helps reduce undesired refraction because it has the same refractive index as glass
immersion oil
type of microscope used to diagnose syphilis, examine living microbes in liquid suspensions
darkfield microscope.
syphilis
treponema pallidum, corkscrew microbes
permits detailed examination of internal structures of living microbes
phase-contrast microscope
uses two beams of light and prisms thereby adding contrasting colors to the view. similar to phase-contrast microscopy
Differential Interference contrast (DIC) microscopy
employs a UV light source. requires specimen to be tagged with fluorchrome dyes that attach to specific antibodies. very rapid diagnostic test
fluorescent microscopes
what bacterium is responsible for tuberculosis and what type of microscope is used to detect its presence?
Mycobacterium Tuberculosis. fluorescent microscope
fluorescent dyes can be attached to specific antibodies which in turn can be used to label specific microbes
fluorescent antibody technique, or immunofluorescence
specimens are stained with fluorchromes so they emit light, then scanned in fine cross-sectional slices with short-wavelength blue light. computer then contructs 3D complete image
confocal microscopy
chancre
painless ulcer caused by syphilis
can track the activity of living cells in real time
two-photon microscopy
sends sound waves through specimen. can resolve as small as 1 micrometer
scanning acoustic microscopy (SAM)
uses beam of electrons rather than light and uses magnets rather than lenses. resolves smaller than 0.2 micrometers. used to view viruses
electron microscopy
electron microscope that provides only 2D and can magnify up to 100,000X
transmission electron microscope
electron microscope that provides 3D and can magnify up to 10,000X
scanning electron microscope
