Discuss the principle behind Gram Staining?

Question

Discuss the principle behind Gram Staining?

Answer 1

Just adding to niotulove's answer... The peptidoglycan layer retains the purplish dyes in gram positive cells. But gram negative cells have a thinner peptidoglycan layer so they can't retain the purple dyes. So when it is washed with alcohol (ethanol), the purple dyes are washed away and the counter stain (safranin) dyes it pink/red when it is applied.

Answer 2

gram staining is used to determine whether bacteria is gram positive or gram negative. if the dye retains the purplish color it is considered to be gpositive if it does not retain the color it is gram negative. it depends on the amount of peptidyglycon in the cell wall

Answer 3

There are two generally different groups of bacteria demonstrated by Gram stain. As a differential stain, it helps distinguish cells with a Gram-positive cell wall from those with a Gram-negative cell wall.

1. Gram-positive bacteria: thick cell wall composed primarily of peptidoglycan and cell membrane; retain crystal violet and stain purple.

2. Gram-negative bacteria: outer cell membrane, thin peptidoglycan layer, and cell membrane; lose crystal violet and stain red from safranin counterstain.

The Gram stain is an important basis of bacterial classification and identification, as well as being a practical aid in diagnosing infection and guiding drug treatment.