Lab exam 1 Flashcards
If the objective lenses of a microscope can be changed without losing focus on the specimen, they are said to be
parfocal
The distance between the two eyepieces of the binocular microscope is called the ________________ distance
interpupillary distance
Microscopes are carried by holding the _______ and _____________
arm and base
The part of the microscope that connects the eyepiece to the nosepiece is the __________________.
body tube
The part of the microscope that contains magnifying lenses to look through is the ____________.
ocular
The part of the microscope that controls the amount of light that passes through the specimen is the
iris diaphragm
The part of the microscope that contains lenses with different powers of magnification is the
nosepiece
The part of the microscope that moves the stage quickly up and down and is used to focus the image under low power is the
coarse adjustment
This objective is used with oil.
100x
Prior to staining, smears of microorganisms are heat-fixed in order to
kill the microorganism and attach it to the slide
The procedure in which a single stain is used to visualize microorganisms is called __________________staining.
simple
Thin films of bacteria that have been air-dried onto a glass microscope slide are called
bacterial smear
The cell wall of a bacteria is __________________________ charged as it relates to staining.
negative
The background is stained and not the bacteria in this staining procedure
negative stain
The Gram staining procedure differentiates bacteria based on the chemical composition of which cell structure?
cell wall
After the counter stain has been added, gram positive organisms are stained _______________ and gram negative organisms are stained ___________________________ .
purple, pink
If a microbiology lab technician left the safarnin out of the Gram stain procedure, what would be the result?
gram-positive cells would be purple and gram-negative are colorless
The Gram staining procedure is an example of:
differential staining
In the Gram staining procedure, the mordant is
iodine
Where do gloves go when done with the lab?
bio hazard trash
What should you wipe lab table with before and after lab?
10% chlorine bleach
Where does broken glass go?
sharps box
What is the preferred method of decontaminating microbiological waste?
the autoclave
BSL-1
nonpathogenic organisms
BSL-2
organisms that present a moderate environmental and/ or health hazard
BSL-3
organisms are of local or exotic origin and are associated with respiratory transmission
BSL-4
high prob. of organisms causing lethal infection
What temp does the autoclave have to be at?
121 Celcius for 15 minutes
streak plate technique
bacterial dilutions occur on the plate, used to isolate a mixed culture to a pure culture
spread plate
bacterial dilutions occur in the test tube, isolate mixed cultures to a pure culture based on serial dilutions
How do you prepare a sterile work area?
decontaminate with ethanol and light bunsen burner, sterilize insulator
acidic stains
stain alkaline structure
bind to positively charged components like proteins
(eosin, Nigrosin
basic stains
more common, stain acidic structures
bind to negatively charged cell parts like cell wall
(methylene blue, safarnin
Kinds of special stains
negative, flagellar, fluroscent
cocci
spherical
bacili
rod shape
spirals
curved walls
vibrious
slightly curved rods
Endospore stain
- Prep smear
- Add methylene blue
- Rinse with water
- blot slide with bibulos water
- view with objective lenses
negative stain
- Place congo red in 2 separate circles
- using a flamed inoculating needle, pick up bacillus subitilis and stir into congo red
- scrape material from teeth with toothpick and stir into second drop of congo red
- air dry
- flood with acid alcohol until it turns blue
- air dry
- view with lenses
