agar slants
What is useful as media for cultivation and maintenance of stock cultures?
entire, lobbed, or irregular
The edge of growth on a slant may be....
incubation time and temperature
what are the 2 important factors influencing growth?
methylene blue, crystal violet, and safrinin
what are common stains?
it kills the bacteria and makes it adhere to the slide
why are basic stains applied to bacterial smears that have been heat fixed?
cell morphology, size, and arrangement
what does staining show?
filiform growth
dense and opaque with a smooth edge
friable
crusty
friable
most species in the genus mycobacterium produce ___ growth
filiform, friable, spreading edge, translucent, transparent
types of growth
pigmented
temperature makes it ____ or not
float on top of the medium and produce a type of surface membrane, sink to the bottom, produce uniform fine turbidity, clump
growth characteristics in broth
pellicle
the type of surface membrane produced when an organism floats on top of the medium
sediment
sink to the bottom
uniform fine turbidity
evenly cloudy throughout
flocculent
clump
ring
growth at top around edge
solvent and a colored molecule
stains are solutions consisting of....
chromogen
the colored molecule in stains is called
chromophore
the portion of the chromogen that gives it its color
auxochrome
is the charged portion of a chromogen and allows it to act as a dye through ionic or covalent bonds between the chromogen and the cell
basic stains
where the auxochrome becomes positively charged as a result of picking up a hydrogen ion or losing a hydroxide ion
negative charges
basic stains are attracted to the ___ ___ on the surface of most bacterial cells
transparent
what color is the cytoplasm?
30-60 seconds
how long should you stain with crystal violet?
up to 1 minutes
how long should you stain with safranin?
30-60 seconds
how long should you stain with methylene blue?
coccus, cocci
sphere shaped (cell morphology)
bacillus, bacilli
small rod shaped (cell morphology)
spiral
twisted in helices, corkscrews (cell morphology)
strepto
forms long chains
staphylo
irregular, grape-like cluster
the cell would appear larger than it is
what is a consequence of leaving a stain on a bacterial smear too long?
the cell would appear clear
what is a consequence of leaving a stain on a bacterial smear not long enough?
Organisms with high surface to volume ratio (rods,spirilla) often survive better in moist environments where their ability to exchange materials with their surroundings is an asset for nutrient acquisition of water loss is not a concern.
would a coccus or a rod be better adapted to a moist environment?
Cocci, with their low surface to volume ratio are less efficient at exchange with the environment than rods, but are at an advantage in a dry environment where they lose water dehydrate more slowly than rods.
would a coccus or a rod be more likely to survive in a dry environment?
basic
does negative or basic staining require heat-fixing?
acidic, negative
the negative staining technique uses a dye solution in which the chromogen is _____ and carries a ____ charge
it produces minimal cell shrinkage
why would we use a negative stain when we need to determine an accurate size?
The acidic stain cannot penetrate the negatively charged cell wall
Why doesn't a negative stain colorize the cells in the smear?
background = red; cells = blue.
The eosin is a negative stain and cannot penetrate the cell wall, so it would just stain the background
Eosin is a red stain and methylene blue is blue. What should be the result of staining a bacterial smear with a mixture of eosin and methylene blue?
bacilli
bacterial cells that are rod shaped are called
streptococci`
spherical cells arranged in a chain are called
vibrio
bacterial cells that are curved rods or comma-shaped are called
spirilla, spirochetes
helical bacteria are referred to as _____ or _____
secondary
in a differential staining technique, the stain that is used after the decolorization step is called the counter stain, or_____ stain
differential
the type of stain designed to show differences between various organisms or cellular structures
simple
a stain that uses only one dye to stain all cell types
primary
the first dye applied in a differential staining technique
gram negative
cell walls contain a thin layer of peptidoglycan
gram positive
cell walls contain a thick layer of peptidoglycan
safranin
the name of the counterstain, or secondary stain, typically used in the gram stain technique
methylene blue
the counterstain used in the acid-fast stain is
carbolfuchsin
in the kinyoun acid-fast staining method, highly concentrated _____ is used to penetrate the cell wall and colorize acid-fast bacterial cells
carbolfuchsin
in the kinyoun acid-fast staining method, highly concentrated _____ is used to penetrate the cell wall and colorize acid-fast bacterial cells
blue
if carbolfuchin was omitted from the ai-fast stain, what color would non-acid fast cells appear?
endospores
in order to withstand hostile conditions and facilitate survival, some bacteria produce resistant structures known as
safranin
is used to stain the vegetative cells in the endospore staining procedure
malachite green
is used to stain the endospore in the endospore staining procedure
crytal violet
which stain is used to stain the cytoplasm of the cells in the capsule stain?
cytoplasm
in the capsular stain, the counterstain dyes the ___