SI worksheet Flashcards
utilizing dyes during the staining process helps to increase the ______ of the organism
contrast
what is the part of the dye that carries the positive or negative charge
chromophore
a microbiologist wants to look closely at the surface of a virus, they would use a
scanning electron microscope
which dyes are considered simple stains
malachite green, safranin, crystal violet
describe simple stains
no differentiation between cell types, uses basic and differential stains
do gram positive organisms pick up the counter stain during a gram stain procedure?
yes
what is a decolorizer composed of
alcohol and acetone
what is a primary stain
crystal violet
what is a counterstain
safranin
what is a mordant
iodine and it adheres the stain to the cell(keeps it on there)
what microscope constructs a 3D image of a thick structure such as a living cell
confocal(plane by plane, attached to computer)
acid fast organisms do nt receive stains well because
they have waxy content in their cell walls preventing staining
describe basic dyes
they are used in simple staining, they have positive charges, they are attracted to negatively charged structures in the cell
steps in the gram staining procedure
primary stain, mordant, decolorizer, counterstain
why can smaller organisms be seen using an electron microscope
electrons have shorter wavelengths than light
negative staining is used to make microbial ______ visible
capsule
what does pleomorphic mean
the cell has multiple shapes
on what evidence did aristotle base his belief of spontaneous generation
observing living things seemingly arise from non living matter
what three domains of life include microbes
bacteria, archaea, eukarya
unicellular organisms that are placed in this junk category are known as
protista
based on endosymiotic theory which two organelles are thought to have arisen from engulfed bacteria
mitochondria and chloroplasts
uses a series of lenses and uses visible light for illumination
compound light microscopy
uses a darkfield condenser and an opaque disk that blocks direct light;specimen appears light against a dark background
darkfield miscroscopy
uses direct and diffracted light in one beam to form an image of the organism in light, gray and black; permits detailed examination of living organisms
phase-contrast microscopy
uses differences in refractive indexes and two beams of light instead of one; image appears brightly colored and 3D
differential interference contrast microscopy
organisms absorbs UV lights and gives off visible light; organism may be tagged with a fluorochrome
fluorescence microscopy
one plane of a specimen is illuminated; uses fluoresce; may be attached to a computer to generate a 3D image
confocal microscopy
a beam of electrons is focused onto a small area of the organism; image is 2D
transmission electron microscopy
uses a beam of electrons reflected off the organism; allows 3D like view of surface
scanning electron microscopy
uses sharp probe to move along surface of organism; transmits image to a computer; has increased resolving power
scanned probe microscopy
