When alcohol is added to gram-negative bacteria, what is their typical response?

In the context of gram-negative bacteria, the addition of alcohol leads to the decolorization of these cells. Gram-negative bacteria have a thinner peptidoglycan layer surrounded by an outer membrane, which makes them susceptible to the effects of alcohol during the gram staining process.

When alcohol is applied, it disrupts the outer membrane and extracts lipids, compromising the integrity of the cell wall and allowing the crystal violet stain (which colors cells purple initially) to wash out. As a result, the cells lose their color and become colorless.

This property is distinct from gram-positive bacteria, which retain the crystal violet stain because of their thicker peptidoglycan layer and do not lose the coloring agent when alcohol is applied. Thus, the response of gram-negative bacteria to alcohol is a reliable indicator of their structural characteristics and the differences between gram-positive and gram-negative organisms in laboratory practices.