Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
49 Cards in this Set
- Front
- Back
how does a negative stain differ from other stains?
|
The dye is acidic and has a negative charge
|
|
What is a benefit of using a negative stain?
|
You don't have to heat fix (good for fragile organisms/cells). Also, it produces minimal cell shrinkage.
|
|
What is the theory behind using an acidic stain?
|
The negative charge repels the stain, so the cell remains uncolored against a colored background.
|
|
What are two common acidic stains
|
nigrosin and eosin
|
|
What is an autoclave bag?
|
It is used for decontamination. The items from the bag are put into an autoclave to sterilze them at 121 degrees
|
|
needles and glass should be put in
|
sharps container
|
|
bright field microscopy is the
|
most commonly used
|
|
the best limit of resolution is
|
.2 micrometers
|
|
total magnification is
|
mag of objective x mag of ocular
|
|
eyeball to base of microscope
|
ocular lens, objective lens, specimin, condensor, light
|
|
Actual limit of resolution
D= |
wavelength /
NA condensor + NA objective |
|
Numeric Aperture is the
|
measure of a len's ability to capture light coming from the specimin and use it to make an image
|
|
stage micrometer
|
used to calibrate microscope
(no numbers on it) |
|
ocular micrometer
|
is a scale with uniform incrmenets of unknown size. It has to be callibrated with the objective
|
|
diplo
strepto tetrad sarcina staphylo |
two cocci
chain cocci four cocci eight cocci grape like structure |
|
bacillus
|
rod
|
|
coccobacillus
|
short rod that could be confused with cocci
|
|
vibrio
|
curved rod
|
|
pleomorphic
|
grows in a variety of shapes
|
|
basic steps in making a bacterial smear
|
drop water, add bacteria w innoc. loop, spread, air dry (flame loop again), pass through flame
|
|
2 benefits of making bacterial heat fixed smear?
|
it makes the bacteria adhere to the slide and it coagulates the protein to make them more visible
|
|
drawbacks to heat fixing a smear?
|
it distorts the cells to an extent.
|
|
theory behind basic stain
|
basic stains are attracted to the negative charge on the surface of most bacterial cells. Thuis the cell becomes colored
|
|
3 common basic stains
|
methylene blue, safranin, crystal violet
|
|
how is negative stain different from other stains?
|
The dye is acidic and has a negative charge
|
|
examples of differential stains?
|
gram, acid fast, capsule, spores or flagella
|
|
differential stains are also referred to as
|
structural stains
|
|
what is the Ziehl-Neelsen (ZN) method and sequence of steps
|
Acid fast stain.
heat fix emulsion, cover smear w paper towel and carbolfucshin stain, steam for 5 min, remove paper, rinse, decolorize w acid alcohol, rinse w distilled water, counterstian w M. blue 1 min., blot dry |
|
function of the methylene blue in acid fast?
|
It stains the acid fast negative cells
|
|
2 diseases caused by mycobacteria?
|
leprosy and tuberculosis
|
|
function of capsule stain
|
detects cells capable of producing an extracellular capsule.
|
|
capsule production
|
increases virulence in some microbes, making them less vulnerable to phagocytosis
|
|
capsule technique
|
stains around cells. The capsule remains unstained and appears as a white halo against a colored background.
|
|
capsules are composed of
|
polypeptides which are difficult to stain
|
|
what is an endospore
|
a dormant form of bacterium thatb allows it to survive lean environmental conditions
|
|
Endospore stain process
|
heat fixed smear, cover w paper. apply malachite green steam 5 minutes, counterstain w safranin 1 min, rinse, blot dry
|
|
endoposre stain chemicals
|
malachite green and safranin
|
|
2 genera of bacteria w endospores
|
bacillus and clostridium
|
|
would bacteria be likely pathogenic at 25 degrees?
|
Probably not psychrotrophs, usually are not pathogenic
|
|
would bacteria be likely pathogenic at 37 degrees?
|
mesophiles,
|
|
free living
|
microbe does not reside on plant or animal host and are not pathogenic.
|
|
opportunistic pathogen
|
capable to cause disease
|
|
reservoir
|
area including sites outside the host where microbe resides and serves as a poential source of infection
|
|
pathogens
|
associated w host
|
|
shape
|
circular, irregular, punctiform (tiny, pinpoint)
|
|
margin
|
entire (smooth, no irregularites), undulate (wavy), lobate (lobed), filamentous, or rhizoid (branched like roots)
|
|
elevations
|
flat, raised, convex, pulvinate (very convex), and umbonate (raised in center)
|
|
texture
|
mucoid, moist or dry
|
|
pigment description
|
color, opaque, translucent, shiny or dull
|