And because of this relatively large thickness of the Peptidoglycan cell wall, when we actually stain our bacteria with some type of purple dye, that purple color remains within that cell because it cannot leave, it cannot leak out of our relatively thick Peptidoglycan wall. And so, under the microscope, when we actually take our bacteria, the Grampositive bacteria, and stain it with the purple dye, those bacterial cells will appear purple under the microscope. So Grampositive bacterial cells are cells that are characterized by thick cell wall. When we stain the cell with our purple dye, the thick layer of Peptidoglycan prevents the purple stain from leaking out back into our surroundings when we wash those bacterial cells with water. So under the microscope, Grampositive bacterial cells appear purple. Now, in both types of these cells, the periplasmic space, as I mentioned earlier, basically contains important hydrolytic enzymes that break down different types of molecules that are then ingested into the cell so that the cell can use them to basically function properly.