What is the primary component of a bacterial cell wall?

The primary component of a bacterial cell wall is peptidoglycan. Peptidoglycan is a polymer that consists of sugars and amino acids and plays a crucial role in maintaining the structural integrity and shape of bacterial cells. It provides rigidity to the cell wall, helping to protect bacteria from osmotic pressure and mechanical damage, which is vital for their survival in various environments.

In contrast, cellulose is a polysaccharide primarily found in the cell walls of plants and some algae, and chitin is a component of the cell walls of fungi and the exoskeletons of arthropods. Lipids, on the other hand, are important components of cellular membranes, but they do not constitute the structural framework of bacterial cell walls. Thus, peptidoglycan is specifically unique to bacteria, making it the correct answer.