Experiment :Bacterial Staining
Questions :
1. What are the advantages of differential staining procedure
over the simple staining techniques?
The differential staining determine the shape ,arrangement ,
and gram reaction while the simple staining only determine the
morphology .
So the differential stain tell the chemical composition of
bacteria .
the simple staining technique are can help you identify the best
type of staining to use in a lab. Differential staining
techniques, such as the gram staining method, uses different
types of dyes to highlight different types of bacteria.
2. Cite the purpose of each of the following reagents in a
differential staining procedure
a. primary stain:
Passes the color of the stain to all of the cells and to impart
its color to all cells .
b. Counterstain:
Used to stain red the cells that have been decolorized (Gram –
cells ) . and Determine gram-positive (retain the purple primary
color) or gram-negative (undergo decolorization).
c. Decolorizing agent:
remove excess dye of cell and may or may not remove the
primary stain from entire cell or only certain cell structure
Increases the cells' affinity for a stain.
3. Why is it essential that the primary stain and the
counterstain be of contrasting color?
So it can distinguished from each other .
4.Which is the most crucial step in the performance of the
Gram staining procedures?
Decolorizing step .
as crystal violet stain will be removed from both G+ve & G-ve
cells if the decolorizing agent (e.g. alcohol ) is left too long .
5. Because of snowstorm, your regular laboratory session
was canceled and the Gram staining procedure was
perform on cultures incubated for a longer period of time.
Examination of stained Bacillus Cereus slides revealed a
great deal of color variability, ranging from an intense blue
to shades of pink. Account for this result.
The cell wall will begins to leak after the cell dies and the
stain does not hold as well.