Learning Target: Bacteria: The Good, the Bad, & the Ugly

1. 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

2. Learning Target: Bacteria: The Good, the Bad, & the Ugly • Bacteria: • 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

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

4. Learning Target: Bacteria: The Good, the Bad, & the Ugly • Bacteria: • 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

5. 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 epidermidison skin

6. 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

7. 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

8. 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

9. 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

10. 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]

11. 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

12. 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?

13. 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

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

15. 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

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

17. Why does evolution happen so quickly in bacteria?