Here's why:
* Structural Support: Peptidoglycan provides structural support and rigidity to bacterial cell walls, allowing them to withstand internal turgor pressure (the pressure from water within the cell).
* Protection: It also acts as a protective barrier against osmotic stress and the environment.
* Distinguishing Feature: The presence of peptidoglycan in bacterial cell walls is one of the key features that differentiates bacteria from other organisms like archaea and eukaryotes.
Note: While peptidoglycan is present in the cell walls of bacteria, there are variations in its structure and thickness between different bacterial species. This variation is used to classify bacteria into two main groups:
* Gram-positive bacteria: Have a thick layer of peptidoglycan that retains the Gram stain (purple color).
* Gram-negative bacteria: Have a thin layer of peptidoglycan sandwiched between two membranes. They do not retain the Gram stain (appear pink).
