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
Cell wall of bacillus anthracis is composed of - 
Select and explain. 
A. Peptidoglycan, B. Polysaccharide, C. Lipopolysaccharide, D. Polypeptide
A: Peptidoglycan
Answer: A: Peptidoglycan 
Explanation: Ans. is 'a' i.e., Peptidoglycan The layer just outside the bacterial cytoplasmic membrane is the peptidoglycan layer or cell wall.It is present in both gram-positive and gram negative organisms.The peptidoglycan layer of gram positive bacteria is thick and contain teichoic acid, while in gram negative bacteria it is thin and does not contain teichoic acid.In gram negative organisms, there is outer cell membrane just outside the thin peptidoglycan layer (cell wall)Unique feature of gram negative bacteria dissolution of this layer by ethanol is responsible for gram negativityon gram staining.Chemically,cell wall is composed of mucopeptide (peptidoglycan or murein) scaffolding formed by N acetyl glucosamine and N acetyl muramic acid molecules alternating in chains, which are cross linked by peptide chains.