Unlike eukaryotic cells, bacteria do not possess a cytoskeleton able to transport synthesized proteins to their correct location in the cell. In this article in Microbiology Today (pdf) Leendert Hamoen asks exactly how bacterial cargo navigates through the great cytoplasmic space. He demonstrates how mathematics provided the answer to this intriguing problem when experimental testing became impossible:
The organization of the bacterial cytoplasm is surprisingly complex. Some proteins accumulate near the cell poles, and others are only found at mid-cell. Certain bacterial proteins form spirals, whereas others oscillate between the cell poles. What is so intriguing about this organized distribution of proteins is that bacteria do not contain membranes to compartmentalize their cytoplasm, and they do not have a dedicated cytoskeleton that transports proteins to certain regions in the cell as eukaryotic cells do. How all these bacterial proteins find their proper destination in the cytoplasmic space is a major question in bacterial cell biology, and this problem has intrigued me for a long time.