Name the chemical substance present in the bacterial cell wall.

Solution: Peptidoglycan (also called murein) is the primary structural component of bacterial cell walls.

Chemical Composition:

• N-acetylglucosamine (NAG)
• N-acetylmuramic acid (NAM)
• Peptide cross-links (typically containing D-amino acids)

Bacterial Type	Peptidoglycan Layer
Gram-positive	Thick (20-80 nm)
Gram-negative	Thin (2-3 nm)
Archaebacteria	Absent (pseudopeptidoglycan or protein-based)

Pro Tip: Antibiotics like penicillin target peptidoglycan synthesis, making this knowledge crucial for understanding antibiotic mechanisms.