Question

What does Gram staining entail?

Answer 1

Gram Staining:

1. Staining is an identification technique.
2. This method helps to identify whether the bacteria are Gram-positive or Gram-negative depending on their retention of the Gram stain..
3. This identification technique mainly works on staining, fixing, decoloring, and counterstaining bacterial cells.

Procedure:

1. Staining: The bacteria are stained with crystal violet.
2. Fixing the color: The color is fixed by a mordant medium, mainly iodine.
3. Decoloring: The cells are decolored by alcohol. As the gram-negative bacteria have less peptidoglycan, alcohol washes off the stain and renders them colorless.
4. Counterstaining: The colorless Gram-negative bacteria retain the color of safranin (Counterstain). Gram-positive bacteria remain violet as the peptidoglycan in their outermost layer retains the crystal violet that is not washed off upon treatment with alcohol.