Transcript Bacteria
Bacteria Chapter 23 Standards • Standard 1: Cells • • CLE 3216.1.6 • Describe the relationship between bacteria, protists, and viruses and their host cells • Prokaryotes Bacteria • • • 1. 2. Prokaryote (no nucleus) Small 2 groups: Archaebacteria Eubacteria Eubacteria • Abundant • Cell walls contain peptidoglycan (carb) • 2 cell walls (some) • Exs: E.coli, Streptococci, TB, meningitis Eubacteria Structure Archaebacteria • Lack peptidoglycan • DNA closer to eukaryote • Harsh environments (thick mud, digestive system of animals, great Salt Lake) Archaebacteria Structure Shape 1. Bacilli - rod shaped 2. Cocci - sphere shaped 3. Spirilla - spiral or corkscrew shaped Cell Wall 1. Gram positive detects peptidoglycan (purple) 2. Gram negative no peptidoglycan (red or pink) DNA • A single closed loop of double-stranded DNA attached to one point to cell membrane • Not enclosed in a nucleus • Some have Plasmids - Carry genes that cause disase - Carry genes that provide resistance to atibiotics Capsules and Pili • Capsule – outer covering that protects the cell from drying out or harsh chemicals • - allows cell to connect to host cells and tissue • Pili – help bacteria to connect to each other and to other surfaces Endospores • A thick-coated resistant structure • Helps bacteria to survive in harsh conditions for long times • Resistant to high temps, strong chemicals, radiation, drying out, and environmental extremes Movement • Flagella: • Allows bacteria to move forward, backward, and to rotate and flip Heterotrophs (eat others) 1. Chemoheterotroph- needs to eat other organisms 2. Photoheterotroph - photosynthetic but also need to eat organisms to get carbon Habitats • Bacteria live in certain places and habitats based on their biochemical abilities • Bacteria live in different places based on certain conditions • Ex: oxygen or not temperature of environment pH of environment Autotrophs (make own food) 1. Photoautotroph – use sun to get energy 2. Chemoautotroph use ammonia, sulfur, iron, etc. to get energy Reproduction • 1. 2. 3. Divide quickly if food and space available Binary fission Conjugation Spore Formation Binary Fission • When bacterium replicates DNA & divides in half producing 2 identical daughter cells • Asexual Conjugation • When 2 bacteria exchange genetic material • Creates diversity • Not sexual (no new cells made) Spore Formation • When growth conditions are harsh • Endospore - internal wall in bacteria that surrounds DNA • Ex: Anthrax Bacterial Importance • Decomposers • Nitrogen fixers • Human uses - making food & beverages, remove waste from water, synthesize drugs Bacterial Disease • Any disease causing bacteria = pathogen 1. Bacteria eats cells for food in host – Ex: TB 2. Bacteria release toxins interfering with normal functions (exo and endotoxins) – Ex: strep throat - toxins in blood stream Disease Prevention 1. Vaccine - weakened or killed pathogen - causes body to produce immunity 2. Antibiotics - block the growth and reproduction of bacteria (penicillin) 3. Sterilization - high temps kill bacteria 4. Disinfectant - chemical soln that kills bacteria 5. Food Storage & Processing - cool temps decrease reproduction - boiling, frying, steaming sterilizes Common Bacterial Diseases 1. 2. 3. 4. 5. 6. Lyme Disease Tetanus TB Meningitis Strep Throat Ear Infection