PPT NI BASAS Flashcards
The objective lens
forms the magnified
real image
image is
a product of the
separate magnifying
powers of the two
lenses
Total magnification
Numerical aperture of lens ranges from
0.1 to 1.25
formula for quantifying resolution
RP = wavelength of light in nm/2x numerical aperture of objective lens
Oil immersion objectives resolution is
0.2
In order to get the best resolution possible with a
light microscope, you would want:
A. Long wavelengths of light
B. Short wavelengths of light
C. The wavelength doesn’t affect resolution
B
when a specimen is
darker than surrounding field and used used for live and
preserved stained specimens, what type of microscope is this
Bright-field
best for observing
intracellular structures
phase contract
this microscope is useful in diagnosing
infections
fluorescence microscope
electron micro scopes magnification is about
5,000X and 1,000,000X
Darker areas represent
thicker, denser parts
and lighter areas
indicate more
transparent, less dense
parts. what type of microscope is this
transmission
allow examination of characteristics of live
cells: size, motility, shape, and arrangement
wet mounts and hanging drop mounts
are made by drying and
heating a film of specimen.
fixed mounts
cationic,
positively charged
chromophore
basic dyes
surfaces of microbes are
negatively charged and
attract basic dyes
positive staining
anionic,
negatively charged
chromophore
acidic dyes
microbe repels dye, the
dye stains the
background
negative staining
one dye is used; reveals
shape, size, and arrangement
simple stains
use a primary stain and a
counterstain
differential stains
reveal certain cell parts not
revealed by conventional methods: capsule and
flagellar stains
structural stains
what are the 6 I of culturing microbes
Inoculation
Isolation
Incubation
Inspection
Information gathering
Identification
If an individual bacterial cell is separated from other
cells and has space on a nutrient surface,
isolation
it is the Checking for contaminants (unknown or unwanted
microbes) in the culture.
inspection
Media is classified into 3 properties
Physical state
Chemical composition
Functional type
Provides framework to hold
moisture and nutrients most commonly used
solidifying agent
Agar
what are the 2 most commonly used na media
Nutrient broth
Nutrient agar
chemical contents of media
Synthetic
Complex
General purpose media
Enriched media
contains pure organic and inorganic
compounds in an exact chemical formula
synthetic
contains at least
one ingredient that is not chemically definable
Complex
grows a broad range
of microbes, usually nonsynthetic
general purpose media
contains complex organic
substances such as blood, serum, hemoglobin, or
enriched media
contains
one or more
agents that
inhibit growth of
some microbes
and encourage
growth of the
desired
microbes
selective
contains a substance
that absorbs oxygen
or slows penetration
of oxygen into
medium; used for
growing anaerobic
bacteria
Reducing media
contains sugars that
can be fermented,
converted to acids,
and a pH indicator to
show this reaction
carbohydrate fermentation