The rigid lattice in bacterial cell walls formed by cross-linking polysaccharide chains with short peptides is called what?

• A. Gelatinous capsule
• B. Peptidoglycan
• C. Lipopolysaccharide
• D. Nucleoid

Answer: (B)

The rigid lattice in bacterial cell walls is a mesh made of sugar chains cross-linked by short peptide bridges, providing strength and shape to the cell. This structure is called peptidoglycan (also known as murein). It forms the rigid scaffold that protects the cell from bursting in hypotonic environments. A gelatinous capsule is an outer protective layer some bacteria have outside the wall, not the rigid lattice itself. Lipopolysaccharide is part of the outer membrane of Gram-negative bacteria, contributing to the membrane’s properties rather than forming the cell wall’s cross-linked mesh. The nucleoid is the region in the cytoplasm where the chromosome resides, not a component of the cell wall. So, the rigid cross-linked lattice described is peptidoglycan.