d) all of these
Differential staining allows one to:
a) identify pathogenic vs nonpathogenic bacteria
b) distinguish b/w eukaryotic and prokaryotic cells
c) identify various bacterial types based on color
d) all of these
b) positive
In differential staining, the cells retaining the first or primary stain are usually termed:
a) fast
b) positive
c) resistant
d) simple
b) they resist penetration of an alcohol/HCI solution into their cells
The reason why certain bacteria are termed "acid-fast" is:
a) they release HCI from their cell walls
b) they resist penetration of an alcohol/HCI solution into their cells
c) they require a low pH to grow
d) they use acid to dissolve needed nutrients
c) crystal voilet/iodine
Peptidoglycan and teichoic acid form a molecular complex with:
a) safranin
b) carbol fushin
c) crystal voilet/iodine
d) methylene blue
c) acid-fast
A cell is first stained with carbol fuchsin, decolorized, and then exposed to methylene blue. When observed under the microscope, the cells exhibit a blue color. This indicates that these cells are:
a) Gram-positive
b) Gram-negative
c) acid-fast
d) nonacid-fast
> red (from safranin dye counterstain)
___ is the color of Gram-negative staining reaction under the microscope
> green (from brilliant green dye counterstain)
> blue (from methylene blue dye counterstain)
> red (from safranin dye counterstain)
> violet (from crystal violet dye primary stain)
> acid-alcohol
___ is a chemical used as a decolorizer in the ACID-FAST stain
> safranin
> alcohol
>differential
> acid-alcohol
> violet (from crystal violet dye primary stain)
___ is the color of Gram-positive staining reaction under the microscope.
> green (from brilliant green dye counterstain)
> blue (from methylene blue dye counterstain)
> red (from safranin dye counterstain)
> violet (from crystal violet dye primary stain)
> differential
___ is the type of stain where various types of microbes can be identified based on color
> simple
> differential
> blue (from methylene blue dye counterstain)
___ is the color of ACID-FAST staining reaction under the microscope.
[Note that brilliant green dye is the
alternative
counterstain for the dye used to produce this color reaction]
> green (from brilliant green dye counterstain)
> blue (from methylene blue dye counterstain)
> red (from safranin dye counterstain)
> violet (from crystal violet dye primary stain)
c) acid-fast stain
The stain used to visualize Mycobacteria is:
a) simple stain
b) Gram stain
c) acid-fast stain
d) endospore stain
d) all of these
A normally Gram-positive cell shows up as Gram-variable. Which explanation reveals why this occurred?
a) the smear was too thick
b) the smear was exposed to the decolorizer too long
c) a 48-hour culture was used
d) all of these
b) violet
What color would Gram-positive cells show under the microscope?
a) pink
b) violet
c) blue
d) green
d) retains the color of the primary stain
A microbial cell that shows up positive in a differential stain:
a) is impermeable to water
b) has a thick cell wall
c) has been decolorized
d) retains the color of the primary stain
b) teichoic acid
The chemical found in Gram-positive cell walls not in Gram-negative cell walls that reacts w/the crystal violet-iodine complex is:
a) lipopolysaccharides
b) teichoic acid
c) protein coat
d) peptidoglycan
d) as a fixative or mordant
The iodine in the Gram stain is used:
a) to remove safranin from the cell wall
b) to decolorize
c) as a primary stain
d) as a fixative or mordant
b) safranin
Which stain is used as the counterstain for the Gram stain?
a) iodine
b) safranin
c) cystal violet
d) methylene blue
TRUE
True or False?
Microbes that retain the primary stain after the process is complete are usually condiered Gram "positive.