Learning Target: Bacteria: The Good, the Bad, & the Ugly I Can…Describe how bacteria play both beneficial and negative roles in organisms and the ecosystem I Will… Explain how normal flora bacteria are beneficial in symbiotic relationships with host organisms List examples of how bacteria are used to produce food products List examples of how bacteria benefit the ecosystem Describe examples of pathogenic bacteria List reasons for the evolution of antibiotic resistant bacteria

Learning Target: Bacteria: The Good, the Bad, & the Ugly Single-celled prokaryotic organism (ALIVE) No nucleus or membrane-bound organelles Has a cell wall, but no chloroplast Not an animal, not a plant 3 basic shapes Sphere (cocci) Rod (bacilli) Spiral (spirilla) Environment Aerobes – oxygen Anaerobes – CO2 Facultative aerobes -w/ or w/o O2

Learning Target: Bacteria: The Good, the Bad, & the Ugly Reproduce by: Binary fission (Similar to mitosis) Conjugation Exchange of genetic material through pili

Learning Target: Bacteria: The Good, the Bad, & the Ugly Alive single celled organism Reproduces by binary fission / conjugation Invades cells or releases toxin Treated with antibiotics Virus: Not alive protein capsid around nucleic acid Cannot reproduce – needs host cell Lytic cycle destroys cells Treat symptoms while immune system defeats virus

Learning Target: Bacteria: The Good, the Bad, & the Ugly Normal flora – beneficial bacteria that exist on and in other organisms without harm Often symbiotic (both life-forms benefit) Animal digestive tracts Helps breakdown indigestible material so nutrients can be absorbed Synthesize vitamins to be absorbed Keeps pathogenic organisms away (fill a niche) e.g. E. coli in intestines e.g. Staph epidermidis on skin

Learning Target: Bacteria: The Good, the Bad, & the Ugly Beneficial bacteria – Provides food and services for organisms and ecosystem Fermentation – chemical breakdown of organic material (food) to add flavor and characteristics Probiotics in foods assist immune and digestive system health Yogurt Cheese Pickles Soy sauce Alcohol Vinegar

Learning Target: Bacteria: The Good, the Bad, & the Ugly Ecosystem benefits – Cyanobacteria produce oxygen (Blue-green algae) Recycle Carbon (decompose organic material) Nitrogen fixing (converts atmospheric nitrogen into ammonia to be absorbed by plants) Legumes (peanuts) Mutualistic

Learning Target: Bacteria: The Good, the Bad, & the Ugly Ecosystem benefits – Bioremediation – process of using microbes to breakdown pollutants such as oil spills Polluted water and beaches Biodegradable – ability of bacteria to breakdown a substance Plastics Landfills

Learning Target: Bacteria: The Good, the Bad, & the Ugly Opportunistic Pathogens – Good bacteria gone Bad Bacteria which are Normal flora and beneficial under certain conditions and environments BUT Change the environment or conditions and may become pathogenic e.g. E. coli Normal and beneficial in intestines Leading cause of urinary tract infections

Learning Target: Bacteria: The Good, the Bad, & the Ugly Pathogens – Disease causing Prior to medical revolution Most deaths caused by bacterial infections Sterile technique (disinfection) Antibiotics Alexander Fleming 1928 [1940s]

Learning Target: Bacteria: The Good, the Bad, & the Ugly Bacterial Pathogens Two ways bacteria can cause disease Invading and attacking cells (alters form & function) Release toxins (poisons) Stimulates immune response Inflammation

Learning Target: Bacteria: The Good, the Bad, & the Ugly Antibiotics – Wonder Drug Kills bacteria Prevents reproduction Affects formation of cell wall Why do antibiotics kill bacteria and not our cells?

Learning Target: Bacteria: The Good, the Bad, & the Ugly Antibiotic Resistance Resistance – result of natural selection Bacteria who are resistant and not killed by antibiotic survive and reproduce - passing on the resistant genes Conjugation can exchange genetic material that carries instructions for resistance

Learning Target: Bacteria: The Good, the Bad, & the Ugly Antibiotic Resistance Causes: Overuse – creates selective pressure favoring resistant bacteria over nonresistant

Learning Target: Bacteria: The Good, the Bad, & the Ugly Antibiotic Resistance Causes: Underuse - only destroys the weakest bacteria but not all leaving bacteria not initially killed alive to reproduce passing on some resistance

Learning Target: Bacteria: The Good, the Bad, & the Ugly Antibiotic Resistance Causes: Misuse – Not effective on viral infection (WHY?) Agricultural feed overuse

Why does evolution happen so quickly in bacteria?