There you can see that bacteria are about 10 times bigger than viruses. Bacteria are still quite small and require the aid of a microscope to see the individual organisms. There can be up to one billion cells in a colony. If you follow this link you can see plates containing colonies of cells. The small round dots are called colonies.
Bacteria also come in a variety of shapes and sizes .
Bacteria are found everywhere. Even in the deep sea vents . They can also cause diseases. The reason I said bacteria are gutless is because they are. They lack certain specialized structures called organelles .