Answer: Lipids
Explanation:
In gram staining procedures, alcohol serve as the decolorizing agent.
The alcohol, being an organic solvent dissolves lipids present in the outer cell wall of Gram-negative bacteria, allowing the gram stain to leak out of the thinner peptidoglycan layer unlike in Gram-positive bacteria with thicker peptidoglycan layer
Thus, lipids are the chemical components affected by alcohol.