Questions: True or False: Gram-negative cell walls lose their blue color when washed with alcohol.

The answer is True: Gram-negative cell walls lose their blue color when washed with alcohol.

Explanation:

1. Gram Staining Process: In the Gram staining procedure, cells are initially stained with crystal violet, which is a blue/purple dye.

2. Alcohol Wash: During the decolorization step, alcohol is used to wash the cells. Gram-negative bacteria have a thinner peptidoglycan layer and a higher lipid content in their cell walls, which allows the alcohol to dissolve the outer membrane and wash away the crystal violet stain.

3. Result: As a result, Gram-negative bacteria lose the blue/purple color and become colorless until counterstained with safranin, which gives them a pink/red color.

Therefore, the statement is true.