1. Pathology : scientific study of disease Pathogens : bacteria that cause disease Some bacteria cause disease by producing toxins (poisons) Exotoxins : bacterial proteins; produced by Gram-positive Bacteria –Secreted into the surrounding environment –Tetanus is a disease caused by an Exotoxin. Ever cut yourself or step on a nail and had to take a shot? That was to prevent Tetanus 1

2. Endotoxins : made of lipids & carbohydrates associated with the outer membrane of Gram-negative bacteria, such as E. coli –Not released until bacteria dies –Cause fever, body aches, & weakness, & they damage the vessels of the Circulatory System 2

3. Pathogenic bacteria are a major cause of human death and disease and cause infections such as tetanus, typhoid fever, diphtheria, syphilis, cholera, foodborne illness, leprosy and tuberculosis, pneumonia, Lyme disease, etc. tetanustyphoid feverdiphtheriasyphilischolera foodborne illnessleprosytuberculosis –http://biology.clc.uc.edu/courses/bio106/bact-dis.htmhttp://biology.clc.uc.edu/courses/bio106/bact-dis.htm Bacterial diseases are also important in agriculture, with bacteria causing leaf spot, fire blight and wilts in plants, as well as Johne's disease, mastitis, salmonella and anthrax in farm animals.agricultureleaf spotfire blightwiltsJohne's diseasemastitis salmonellaanthrax –http://en.wikipedia.org/wiki/Bacterial_diseaseshttp://en.wikipedia.org/wiki/Bacterial_diseases 3

4. Many antibiotics are derived from chemicals that bacteria or fungi produce; 3 ways that antibiotics kill bacteria: –interferes with cell wall synthesis, ex: Penicillin –interferes with protein synthesis; ex: Tetracycline –inhibits RNA synthesis; ex: Rifampin They affect only the growth of bacteria without harming the body cells of humans Antibiotic Resistance –Overuse of antibiotics encourages drug-resistant strains to evolve through selection –Mutant bacteria continue to grow 4