The rigid layer that is present in the cell walls of bacteria that is primarily responsible for the strength of the wall is known as

The substance that helps keep the integrity of the bacterial cell wall intact is known as the peptidoglycan. Others also refer to is it as murein or mucopeptide. The bacterial cell wall is necessary for survival because of the high internal pressure present inside of bacteria. Under normal conditions, if the cell wall is removed the bacterial cell will burst.

The peptidoglycan is a layer that can be used to distinguish gram positive bacteria from gram negative ones. G(+) bacteria have a thick layer of this while G(-) have a thinner ones.