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Prokaryotes and Viruses

Prokaryotes and Viruses

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Prokaryotes and Viruses

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  1. Prokaryotes and Viruses

  2. West Nile Virus

  3. West Nile Virus • One of several mosquito-borne viruses in the United States that can infect people • The virus exists in nature primarily through a transmission cycle involving mosquitoes and birds. • Mosquitoes become infected with West Nile virus (WNV) when they feed on infected birds

  4. West Nile Virus Symptoms • Majority of people that become infected with the West Nile virus have no illness or experience only a mild flu-like illness • May include fever, headache and body aches lasting only a few days • Some persons may also have a mild rash or swollen lymph glands • Less than one percent of those infected may develop meningitis or encephalitis, the most severe forms of the disease

  5. How Long has the West Nile Virus Been Around? • Alexander the Great, 336 B.C., conquered a vast empire • It’s speculated that his demise was due to West Nile encephalitis • There is still no human vaccine for West Nile virus

  6. West Nile Virus Takes Off • West Nile Virus is pathogenic, it invades its host and multiplies, causing disease • It’s a flavivirus, traveling inside mosquitoes which act as the transferring agent from host to host

  7. West Nile Virus Takes Off

  8. West Nile Virus Takes Off

  9. Impacts, Issues Video West Nile Virus Takes Off

  10. Microorganisms • Single-celled organisms that are too small to be seen without a microscope • Bacteria are the smallest living organisms • Viruses are smaller but are not alive

  11. The Prokaryotes • Only two groups • Archaebacteria and Eubacteria • Arose before the eukaryotes

  12. Prokaryotic Characteristics • No membrane-bound nucleus • Single chromosome • Cell wall (in most species) • Prokaryotic fission • Metabolic diversity

  13. Prokaryotic Body Plan DNA capsule plasma membrane ribosomes in cytoplasm bacterial flagellum pilus cell wall cytoplasm

  14. Prokaryotic Body Plan cytoplasm, with ribosomes DNA, in nucleoid pilus bacterial flagellum outer capsule cell wall plasma membrane

  15. Prokaryotic Body Plan Prokaryotic body plan

  16. Bacterial Shapes coccus bacillus spirillum

  17. Bacterial Shapes

  18. Bacterial Shapes

  19. Bacterial Shapes

  20. Bacterial Shapes sex pilus

  21. Metabolic Diversity • Photoautotrophs • Chemoautotrophs • Chemoheterotrophs

  22. Gram Stain

  23. Gram Stain Gram stain

  24. Bacterial Genes • Bacteria have a single chromosome • Circular molecule of DNA • Many bacteria also have plasmids • Self-replicating circle of DNA that has a few genes • Can be passed from one cell to another

  25. Prokaryotic Fission

  26. Prokaryotic Fission

  27. Prokaryotic Fission

  28. Prokaryotic Fission

  29. Prokaryotic Fission

  30. Prokaryotic Fission

  31. Prokaryotic Fission

  32. Prokaryotic Fission

  33. Bacterium before DNA replication bacterial chromosome DNA replication begins DNA replication completed parent DNA molecule DNA copy

  34. Membrane growth moves DNA molecules apart New membrane and cell-wall material deposited Cytoplasm divided in two

  35. Prokaryotic Fission - 3 Prokaryotic fission

  36. Conjugation Transfer of plasmid

  37. nicked plasmid conjugation tube

  38. Conjugation Prokaryotic conjugation

  39. EUBACTERIA (Bacteria) ARCHAEBACTERIA (Archaea) EUKARYOTES (Eukarya) Prokaryotic Classification • Traditionally classified by numerical taxonomy • Now increased use of comparative biochemistry

  40. Prokaryotic Classification to ancestors of eukaryotic cells DOMAIN BACTERIA DOMAIN BACTERIA biochemical and molecular origin of life

  41. Eubacteria • Includes most familiar bacteria • Have fatty acids in plasma membrane • Most have cell wall; always includes peptidoglycan • Classification based largely on metabolism

  42. Eubacterial Diversity • Photoautotrophic • Aerobic (Cyanobacteria) • Anaerobic (Green bacteria) • Chemoautotrophic • Important in nitrogen cycle • Chemoheterotrophic • Largest group

  43. Eubacteria Examples of eubacteria

  44. Eubacterial Diversity

  45. Eubacterial Diversity

  46. Eubacterial Diversity

  47. Some Pathogenic Eubacteria • Most are chemoheterotrophs • E. coli strains • Clostridium botulinum • Clostridium tetanus • Borrelia burgdorferi • Rickettsiarickettsii

  48. Some Pathogenic Eubacteria resting spore photo-synthetic cell heterocyst

  49. Some Pathogenic Eubacteria