Question

what would most likely occur if you drenched the bacterial smear in alcohol for 1 minute?
a) all purple stain would escape as the cell wall of both gram - positive and gram - negative bacteria would dissolve
b) the gram - negative bacteria would decolorize, while the more robust gram - positive bacteria would remain unaffected and retain its purple stain

Explanation:

Gram - positive bacteria have a thick peptidoglycan layer in their cell wall. This layer traps the purple stain (crystal violet - iodine complex) during the Gram - staining process. Alcohol (a decolorizing agent) is used in Gram - staining. For Gram - negative bacteria, the thin peptidoglycan layer and the outer membrane allow the purple stain to be washed out (decolorize) when alcohol is applied for the appropriate time (usually a few seconds). However, if alcohol is applied for too long (1 minute in this case), it can disrupt the cell wall of Gram - positive bacteria as well. The cell wall of Gram - positive bacteria is mainly composed of peptidoglycan. Prolonged exposure to alcohol can dissolve the peptidoglycan layer to some extent, causing the purple stain to escape. Gram - negative bacteria already have a more permeable cell wall structure (due to the thin peptidoglycan and outer membrane), and the alcohol will cause their stain to escape.

Answer:

a) All purple stain would escape as the cell wall of both Gram - positive and Gram - negative bacteria would dissolve