MICROBIOLOGY LABARATORY
QUESTIONS AND THEIR ANSWERS
ACCOMPANIED BY A SIMPLIFIED
LAB SUMMARY FOR REVISION
there are many types of staining tech used in microbiology.
which of the following is not a commonly used staining
wright's stain
which of the following stains do not require heat fixation?
capsule stain
The ___ stain provides critical information about
peptidoglycan structure of the cell wall.
Gram
Which of the following stains require heat fixation?
Endospore
Gram
Simple
Acid-fast
Gram stain
a stain that can differentiate between cells that have thick or
thin layers of peptidoglycan in their cell walls
Acid-Fast stain
,a stain that would be appropriate for cells that contain mycolic
acid in their cell walls.
Capsule stain
a stain that enables you to effectively visualize a bacterium's
glycocalyx
Which of the following provides a quick and effective method
used to visualize and determine bacterial morphology and
arrangement?
Simple stain
If you decolorize for more than 30 seconds, gram-positive
organisms will most likely appear ____ in color.
pink
What might happen if you omitted the safranin step while
performing the Gram stain on the mixed culture of gram-
positive and gram-negative cells?
Gram-negative organisms might not be visible
if you omit the Gram's iodine step while preforming the Gram
stain, gram-positive cells will most likely be ____ in color.
pink
What outcome could be expected if you forgot the crystal
violet step while performing a Gram stain?
Gram-positive and gram-negative organisms would stain pink
,Gram-negative cells appear __ after Gram staining whereas
gram-positive cells appear __.
red, purple
If you forget to use the decolorizer, which cell type(s) will
appear purple?
Gram-positive and Gram-negative
What is the primary dye used in the gram staining technique?
crystal violet
What is used as the mordant in the gram staining technique?
Gram's iodine
which of the following correctly describe how the Gram stain
works to color different types of cells?
gram-positive cells retain the purple dye-mordant complex
because of their thick layer of peptidoglycan.
gram-negative cells are decolorized and stained by the pink/red
secondary stain
which of the following describes the correct sequence of the
gram stain procedure?
heat-fixed slide; use of crystal violet, iodine, decolorizer, and
safranin
which of the following are terms used to describe the colored
dyes applied in the Gram staining technique?
, primary and counterstain
what is thought to cause gram-positive cells to retain the
primary stain and the mordant complex whereas gram-
negative cells are decolorized?
the thickness of the peptidoglycan layer
Place these reagents in the proper order of their use in the
Gram staining techique
crystal violet
gram's iodine
decolorizer
safranin
The name of the counterstain, or secondary stain, typically
used in the gram stain technique is ___
safranin
what type of cell wall contains a thick layer of peptidoglycan
and no outer membrane?
gram-positive
why might it be important to perform a gram stain on
bacterial cells?
as part of the information used to choose an appropriate
antibiotic Tx
QUESTIONS AND THEIR ANSWERS
ACCOMPANIED BY A SIMPLIFIED
LAB SUMMARY FOR REVISION
there are many types of staining tech used in microbiology.
which of the following is not a commonly used staining
wright's stain
which of the following stains do not require heat fixation?
capsule stain
The ___ stain provides critical information about
peptidoglycan structure of the cell wall.
Gram
Which of the following stains require heat fixation?
Endospore
Gram
Simple
Acid-fast
Gram stain
a stain that can differentiate between cells that have thick or
thin layers of peptidoglycan in their cell walls
Acid-Fast stain
,a stain that would be appropriate for cells that contain mycolic
acid in their cell walls.
Capsule stain
a stain that enables you to effectively visualize a bacterium's
glycocalyx
Which of the following provides a quick and effective method
used to visualize and determine bacterial morphology and
arrangement?
Simple stain
If you decolorize for more than 30 seconds, gram-positive
organisms will most likely appear ____ in color.
pink
What might happen if you omitted the safranin step while
performing the Gram stain on the mixed culture of gram-
positive and gram-negative cells?
Gram-negative organisms might not be visible
if you omit the Gram's iodine step while preforming the Gram
stain, gram-positive cells will most likely be ____ in color.
pink
What outcome could be expected if you forgot the crystal
violet step while performing a Gram stain?
Gram-positive and gram-negative organisms would stain pink
,Gram-negative cells appear __ after Gram staining whereas
gram-positive cells appear __.
red, purple
If you forget to use the decolorizer, which cell type(s) will
appear purple?
Gram-positive and Gram-negative
What is the primary dye used in the gram staining technique?
crystal violet
What is used as the mordant in the gram staining technique?
Gram's iodine
which of the following correctly describe how the Gram stain
works to color different types of cells?
gram-positive cells retain the purple dye-mordant complex
because of their thick layer of peptidoglycan.
gram-negative cells are decolorized and stained by the pink/red
secondary stain
which of the following describes the correct sequence of the
gram stain procedure?
heat-fixed slide; use of crystal violet, iodine, decolorizer, and
safranin
which of the following are terms used to describe the colored
dyes applied in the Gram staining technique?
, primary and counterstain
what is thought to cause gram-positive cells to retain the
primary stain and the mordant complex whereas gram-
negative cells are decolorized?
the thickness of the peptidoglycan layer
Place these reagents in the proper order of their use in the
Gram staining techique
crystal violet
gram's iodine
decolorizer
safranin
The name of the counterstain, or secondary stain, typically
used in the gram stain technique is ___
safranin
what type of cell wall contains a thick layer of peptidoglycan
and no outer membrane?
gram-positive
why might it be important to perform a gram stain on
bacterial cells?
as part of the information used to choose an appropriate
antibiotic Tx
