Transcript Bacteria
Bacteria Characteristics of Bacteria. • • • • Smallest and simplest living thing Have no organelles, including no nucleus Genetic material = simple circular chromosome They have cell walls to protect them from outside pressure • Transmitted through: – air – Water – Human Contact – Contaminated Food Bacterial Shape & Arrangement SHAPES: • Coccus: round • Bacillus: rod shaped • Spirillum: spirals ARRANGEMENTS: • Diplo: pairs • Staphylo: clusters • Strepto: chains Types of Metabolism Obligate aerobes: • require oxygen to live • Example: E.coli lives in mammal intestines Obligate anaerobes: • Killed in the presence of oxygen • Example: Syphillis Facultative aerobes: • can live with or w/o oxygen Bacterial Adaptations for Survival. ENDOSPORES: • Hard, outer covering produced during harsh environments • Resistant to: – drying out – boiling • Metabolism slows down inside endospore • Resumes growing when conditions are more favorable Endospore TOXIN PRODUCTION: • Some bacteria produce poisons when the Endospore begins to grow • Toxins kill off other bacteria – providing more food for the surviving bacteria • Some toxins are deadly • Examples: – Botulism (food poisoning) – Tetanus (lock jaw) Bacterial Reproduction BINARY FISSION: • Asexually Reproduction • Splitting in ½ after copying the DNA • Occurs very quickly • Will stop reproducing only if: – Run out of food – Dry up – Poisoned by own wastes DRAW ON LEFT PAGE!!! CONJUGATION: • Sexual Reproduction • Transfers all or part of the DNA between 2 bacteria • Transfer through a projection called a Pilli • Occurs when threatened, • Hope to pass on DRAW ON LEFT PAGE genetic material – Will make the bacteria resistant to changes. Immune Response in Humans. • I.S. fights off invaders which are called ANTIGENS • Our bodies produce ANTIBODIES against each antigen • Antibodies lock on to the pathogen’s active site or prevent its attachment Types of immunity • Resistance to Disease Passive Immunity: • Antibodies are: – Acquired – Passed from mother to child – Injected Active Immunity: • Exposure to antigen: – Recovery of disease – Through vaccination Vaccination: • Injection of: – Weakened Antigen – Pieces of antigens Bacterial Uses FOOD FLAVORINGS: • Food flavors are produced by: – Fermentation – Bacterial wastes, etc. • EX: Vinegar, yogurt, butter, cheese, pickles, buttermilk, sauerkraut ANTIBIOTIC PRODUCTION: • Some bacteria produce antibiotics that will kill other forms of bacteria • Antibiotics kill bacteria only!