What is the major difference between Gram-positive and Gram-negative bacteria?
Microbiologists use the Gram stain to aid in identification of bacteria.
- 9 years agoFavorite Answer
Gram-positive bacteria turn purple in a Gram stain because their cell walls contain a peptidoglycan layer and a cell membrane. The chemicals are able to penetrate these two layers.
Gram-negative bacteria contain an outer cell membrane, a peptidoglycan layer, and an inner cell membrane. The chemicals can't go through the cell wall as well and become pink.