1. Domain Bacteria 4 Single Celled 4 Prokaryote - no nucleus or other organelles 4 0.5 to 10 micrometers long (100 times smaller than the cells we’ve looked at)

2. Domain Bacteria 4 Have a cell wall - providing protection 4 DNA is arranged in a single closed loop. 4 Many use flagella and cilia to move 4 Some are heterotrophs others are autotrophs

3. Important Roles of Bacteria 4 In our small intestine helping us digest our food. 4 Many species are important in decomposing dead organic matter. They are present in our soil. Also used in sewage treatment plants. 4 Used in processing some foods - for example yogurt, sour cream 4 Used in industry and mining. 4 Used in cleaning up chemical and oil spills.

4. Bacteria and Disease 4 Pathology - scientific study of disease 4 Pathogens - bacteria that cause disease - e.g., lyme disease, salmonella, strep throat, mononucleosis 4 Antibiotics are drugs that combat bacteria. For example, penicillin interferes with the formation of the bacteria’s cell wall. 4 Antibiotic resistance has become a major concern. Because antibiotics are overused diseases that used to be easy to treat are becoming more difficult to treat.