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Bacteria and Viruses, Protista, and Fungi

Bacteria and Viruses, Protista, and Fungi. Chapters 22, 23, 24. The new Three Domain System To which domain is prokaryotic Archaea more closely related?. I. Why put prokaryotic Archaea in a separate domain?. Archaebacteria. Methanogens Swamps, sewage Halophiles

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Bacteria and Viruses, Protista, and Fungi

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  1. Bacteria and Viruses, Protista, and Fungi Chapters 22, 23, 24

  2. The new Three Domain System To which domain is prokaryotic Archaea more closely related?

  3. I. Why put prokaryotic Archaea in a separate domain?

  4. Archaebacteria • Methanogens • Swamps, sewage • Halophiles • Brackish ponds, salt lakes, hydrothermal seafloor vents • Extreme Thermophiles • Acidic soils, hot springs, coal mines, hydrothermal vents Optical Illusion

  5. II. Viruses A. Introductory information a. Definition = “obligate intracellular parasites” b. Tobacco mosaic virus was crystallized and first seen with TEM in 1935. B. Structure a. Capsid – protein coat, composed of protein subunits, form rods, polyhedrons, and complex structure b. Envelope – found in viruses that infect animals, outer membrane derived from host cell c. Genome – DNA or RNA

  6. Animation ESummary of the entire lytic life cycle of a bacteriophage. C. Lytic cycle of a T4 bacteriophage

  7. D. Lysogenic cycle (latent period viruses) a. After insertion, viral DNA incorporates itself into a specific site within the bacterial DNA (viral DNA is now called a prophage) b.Prophage is replicated during every subsequent cell division of the bacterium c. Prophages sometimes make harmless bacteria toxic, e.g. diphtheria, botulism, scarlet fever d. Occasionally prophage leaves bacterial chromosome and becomes lytic

  8. Replication of animal viruses (contain DNA or RNA) (Note that cell is not destroyed and source of envelope.) (This is an influenza (flu) virus)

  9. III. Protista • Origin of eukaryotes—endosymbiont hypothesis -capture and subsequent symbiotic relationship between large heterotrophic eukaryote and small heterotrophic and photosynthetic prokaryotes

  10. Major types of protists 1. Protozoans—one-celled heterotrophs a. Flagellates-move with one of more flagella, Giardia, trypanosomes b. Amoebas-move and feed by pseudopodia c. Ciliates-move and feed with cilia, free- living, two nuclei, Paramecium d. Apicomplexans-all parasitic, Plasmodium

  11. 2. Slime molds—have unicellular and multi-cellular life stages

  12. 3. Algae—photosynthetic protists a. Diatoms-unicellular, glassy cell walls containing silica b. Dinoflagellates-unicellular, two flagella c. Green algae-unicellular Chlamydomonas, colonial Volvox

  13. 4. Seaweeds—large, marine, multicellular bodies a. Brown algae-largest, kelp (100 m.) b. Red algae c. Green algae-multicellular

  14. V. Fungi A. General characteristics 1. Eukaryotic 2. Absorptive heterotrophs 3. Reproduce sexually and asexually (spores) B. Structural characteristics 1. Some are unicellular (yeast) 2. Most have a thallus (body) called a mycelium, which is composed of hyphae, which are a. Filamentous, and b. Septate or aseptate 3. Often found in symbiotic relationships a. Lichens (fungi + algae) and plant roots, helps plant take up nutrients

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