Bacteria live almost anywhere imaginable, from inside your intestines to the bottom of the ocean floor. Of the thousands of types of bacteria, only a small fraction causes disease.  In fact, there are many bacteria that are not only beneficial to humans but also some that are critical to our survival! This is especially true for certain bacteria in the gut. 

In this part of our lesson on infectious organisms we will look at how bacteria differ, not only in their structure, but also in the role they play in our environment.

Common Properties | Bacteria | Virus | Protozoa | Fungi