Notes

1. Gram staining a bacteria is used to determine whether a specific strand of bacteria is Gram-positive or Gram-negative. Knowing whether the bacteria is Gram-positive or Gram-negative is important since it aids in identifying that specific bacteria. It also aids medical practitioners in determining what kind of medicine would be potent to kill that specific bacteria. Antibiotics is one example wherein Gram-negative bacteria is more resistant while Gram-positive is more susceptible.
2.
a. Mordant- promotes the retention of the primary stain on the bacterial cells.
b. Primary Stain- primary dye used to mark the outermost layer of Gram-positive and Gram-negative bacteria.
c. Decolorizer- Shrinks the pores of the peptidoglycan layer. Since the outer membrane of the Gram-negative bacterial cells are sensitive to the decolorizer, such as ethanol, it removes the outer membrane of Gram-negative bacterial cells rendering Gram-negative bacteria colorless.
d. Counterstain- applied to the colorless bacterial cells to differentiate Gram-negative cells from Gram-positive cells.
3. What is the difference between Gram-positive bacteria and Gram-negative bacteria.
The difference between Gram-positive and Gram-negative bacterial cells is the thickness of the peptidoglycan layer wherein it is much more thicker in the Gram-positive compared to the Gram-negative bacteria. Gram-negative bacteria also has an additional layer, which is the outer membrane containing lipopolysaccharides. The means to treat/kill Gram-negative and Gram-positive bacteria also differ wherein Gram-positive bacteria are more susceptible to antibiotics and Gram-negative bacteria are more resistant.
4. Which steps in Gram staining is most likely to produce poor results?