However, the thinner peptidoglycan layer in a Gram-negative cell is not as effective at trapping the dye, and a “decolorizing” step with ethyl alcohol strips the outer Gram-negative cell wall membrane...However, the thinner peptidoglycan layer in a Gram-negative cell is not as effective at trapping the dye, and a “decolorizing” step with ethyl alcohol strips the outer Gram-negative cell wall membrane, effectively releasing the crystal violet from those cells. At the end of a Gram-stain, all the Gram-positive cells will be deep purple and the Gram-negative cells will be a light red or pink.
