Question

A fellow student is unsure why his gram-negative Escherichia coli is purple. Upon examining the Gram stain kit, you notice it didn't have alcohol. What caused the bacteria to be purple instead of pink

Answer 1

Answer:

if you are not using alcohol (95% ethanol), you are not decolorizing the wall of the gram-negative bacteria, which should get rid of the violet color, therefore the safranin stain, in the next step, won't be absorbed in the wall, and the bacteria will end up being purple due to the previous crystal violet stain of the gram-positive bacteria

Explanation: