how does gram staining separate bacteria into two groups?!?!!? please help!

Question

matt101 · Answer

The Gram stain broadly differentiates bacteria based on the composition of their cell wall. The Gram stain gets stuck in the peptidoglycan layer of the cell wall. Some bacteria have a thick peptidoglycan layer, so it can hold a lot of the stain and make the cells appear purple - these bacteria are Gram-positive. Bacteria with thinner cell walls cannot retain the Gram stain as well and so do not appear a deep purple - these bacteria are Gram-negative. See here: https://en.wikipedia.org/wiki/Gram_staining