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 an 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 genetic material –Will make the bacteria resistant to changes. DRAW ON LEFT PAGE

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!