It includes a cell wall, and in some cases, it also includes a second membrane, a second phospholipid bilayer, as we'll see in just a moment. Now, generally speaking, we have two different types of bacterial cell. We have gram positive and gram negative. And the way we differentiate between these two different types of bacterial cells is by using a technique known as Gram staining. So, before we discuss these two types of bacterial cells, let's discuss what the structure and the function of the cell wall is inside our bacterial cell. So the main function of the cell wall is to basically maintain hydrostatic pressure to be able to resist the hydrostatic pressure that builds up within our cell.