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Viruses

Viruses. Alive or not?. Although some scientists disagree, viruses are classified as NOT ALIVE What do you think? They CANNOT reproduce without a host They are NOT made of cells They DO contain DNA or RNA They CAN evolve. What is a virus?.

brielle-hendrix
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Viruses

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  1. Viruses

  2. Alive or not? • Although some scientists disagree, viruses are classified as NOT ALIVE • What do you think? • They CANNOT reproduce without a host • They are NOT made of cells • They DO contain DNA or RNA • They CAN evolve

  3. What is a virus? - It is a particle of made up of nucleic acid, protein and sometimes lipids that can replicate only by infecting living cells

  4. Virus Structure • Draw this and label it!

  5. Lytic Cycle (infection) • Animation: http://pgl.ufl.edu/modules/mysterious_invaders/lytic.htm

  6. Lytic Cycle • In the lytic cycle, new viruses are produced in the host cell until it bursts (lyses)

  7. Lysogenic Cycle • Animation: http://pgl.ufl.edu/modules/mysterious_invaders/lytic.htm

  8. Lysogenic Cycle • In the lysogenic cycle, the viral DNA is incorporated into the host cell DNA and can stay dormant for years

  9. Vaccines • Viruses can only be prevented with vaccines, they cannot be destroyed with antibiotics • Vaccines are weakened, altered, or blank forms of the virus that cause your immune system to create antibodies • This way if you ever come into contact with the real virus, you already have built up resistance

  10. Diseases • Some diseases caused by viruses are: • The Flu (influenza) • Common Colds • HIV (causes AIDS) • West Nile • Chicken Pox • Herpes • Hepatitis • HPV (genital warts) • Measles • Polio • Smallpox • SARS • Mononucleosis • Ebola

  11. Bacteria

  12. Classification • Unlike viruses, bacteria ARE alive • Bacteria are prokaryotic, and they make up two domains, Bacteria and Archaea

  13. Characteristics • Bacteria live everywhere on earth! • Some bacteria have flagella, which makes them able to move, some cannot move • Some require oxygen to live, some do not • Some are heterotrophic (chemoheterotrophs and photoheterotrophs) and some are autotrophic (chemoautotrophs and photoautotrophs)

  14. Bacteria Shape • Bacteria come in 3 shapes: • Rod, Bacilli • Sphere, Cocci • Spiral, Spirilla

  15. Which is which?

  16. Reproduction • Bacteria can reproduce 2 ways: • Asexually by binary fission: • Sexually by conjugation:

  17. Pros and Cons • What are the benefits to an organism that reproduces sexually? Asexually? • What are some problems associates with reproducing sexually? Asexually?

  18. Bacterial Diseases • Here are some human diseases caused by bacteria: • Tetanus • Lyme Disease • Tuberculosis • Meningitis • Flesh-eating Bacteria • Strep Throat • Whooping Cough • Plague • Syphillus • Leprosy • Anthrax • Gonorrhea • Salmonella

  19. Antibiotics • Bacteria diseases can be cured by antibiotics • The first antibiotic, penicillin, was discovered by accident by Alexander Fleming in 1928 • Penicillin is actually a mold that forms holes in the bacteria’s cell walls • However, bacteria are quickly evolving to become antibiotic resistant • We can no longer fight all bacteria diseases with antibiotics

  20. Antibiotic Resistance • Based on what you know about natural selection, how do bacteria evolve to become drug-resistant when we only take half of our prescription?

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