This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Gentian violet colouration of gram positive bacteria is due to ? 
Select and explain. 
A. Peptidoglycan, B. Capsule, C. Cell membrane, D. None of the above
A: Peptidoglycan
Answer: A: Peptidoglycan 
Explanation: Ans. is 'a' i.e., Peptidoglycan GRAM STAINING The gram stain differentiates bacteria into two broad groups :? Gram positive - Resist decolourization and retain primary stain, appear violet. Gram negative - Decolourised by organic solvents, and therefore, take the counterstain, appearing red.