Gram-negative cells stain purple whereas, Gram-positive cells stain pink or red when using the Gram stain technique,
Gram-positive bacteria cells are able to retain the color of crystal violet dye due to the presence of thick peptidoglycan in their cell walls.
Gram-negative bacteria cells are not able to retain the color of crystal violet dye in their cell walls due to the thinness of the cell wall. Hence, they could not retain the color of the primary stain. Instead, they are counter-stained by safranin.
More on the Gram staining technique can be found here: https://brainly.com/question/14292806
