The outermost layer of both bacterial and plant cells is called the cell wall.

Here's a breakdown:

* Bacteria: Their cell walls are made of peptidoglycan, a complex polymer that provides structural support and protection.

* Plants: Their cell walls are composed primarily of cellulose, a polysaccharide that provides rigidity and strength, allowing the plant to stand upright.

While both bacteria and plant cells have cell walls, they differ significantly in composition and structure.