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. Now, because our cytoplasm of the bacterial cell contains many different proteins and other macromolecules, as well as molecules and ions, we see that the bacterial cell is actually found within a hypertonic environment. And that means we have much more solid inside the cell than outside the cell. And this means that water will flow from a low solid concentration to a high solid concentration.