What is the primary function of peptidoglycan in bacteria?

Peptidoglycan plays a critical role in maintaining the structural integrity of bacterial cell walls, which is essential for their survival. Its primary function is to protect bacteria from osmotic pressure. Bacteria are often found in environments where the concentration of solutes can vary significantly, leading to osmotic stress. The rigidity and strength of the peptidoglycan layer prevent the cell from lysing (bursting) when water enters by osmosis.

This protective barrier also helps to maintain the shape of the bacteria, allowing them to resist mechanical forces. Without the peptidoglycan layer, bacteria would be vulnerable to changes in their environment that could lead to cell lysis. The other functions listed, such as providing energy, assisting in protein synthesis, and facilitating DNA replication, do not accurately reflect the role of peptidoglycan, which is strictly structural and protective in nature.