Lab 3.6: Gram stain Flashcards
Gram stain distinguishes what?
-gram negative and gram positive bacteria
Who and when was gram stain created?
-1884
-Hans Christian Gram
Gram negative
-thin peptidoglycan cell wall
-higher lipid content
Gram positive
-thick peptidoglycan cell wall
-lower lipid content
What can produce false results because of poor technique?
-over decolorize by leaving decolorizer on too long or under decolorize
-inconsistency in the preparation of the emulsion
-some bacteria lose their ability to retain crystal violet iodine complex
If the slide is not rinsed thoroughly or the stain
is allowed to dry on the slide, ?? of stain
precipitate may form and may be confused
with bacterial cells.
-spots
?? from an old or improperly made stain solution can
disrupt the field or stain precipitate may be mistakenly identified
as bacteria
-stain crystals
True or False:
The Gram stain uses a decolorization step after the application of two basic stains.
–false
True or false:
The Gram this stain allows determination of cell morphology, size, and arrangement.
-true
In the Gram stain, after staining with crystal violet, all cells will be ____________
-purple
Upon completion of the Gram stain, Gram-positive cells will appear:
-purple
In the Gram stain, the decolorizing agent is
-alcohol
The Gram stain is a
-differential stain
During a stain procedure, why is it necessary to heat fix the cells?
-to adhere them to the slide
In the Gram stain, the primary stain is
-crystal violet
