Chapter 20 - Bacteria, Viruses, and Protists

 

  1. Characteristics of bacteria

    1. most abundant organisms and widest variety of habitats
    2. prokaryotic
    3. structural features [Figure 20.3]
      1. single, circular chromosome
      2. cell wall (Gram-positive and Gram-negative)
      3. capsule
      4. flagellum
    4. size and shapes
      1. coccus
      2. bacillus
      3. spirillum
    5. metabolic diversity
      1. autotrophic
      2. heterotrophic
    2.  

  2. Kingdoms of bacteria

    1. Archaebacteria

      1. methanogens - "methane makers"
      2. halophiles - "salt lovers"
      3. extreme thermophiles - "heat lovers"
      2.  

    2. Eubacteria

      1. autotrophs
        1. cyanobacteria (blue-green algae)
        2. carry out photosynthesis producing oxygen
        3. some convert nitrogen to ammonia, e.g. Anabaena
      2. heterotrophs
        1. "good species"
        2. "bad species" - pathogens
        3. decomposers
        4. many can form endospores (resting structure that protects against harsh environments)
        5. not as simple as they may seem
    3.  

  3. Bacterial growth and reproduction

    1. don't measure increase in size, but increase in #
    2. may divide every 30 minutes
    3. prokaryotic fission [Figure 20.9]
    4.  

  4. Viruses

    1. characteristics of viruses
      1. non-cellular infectious agent
      2. protein coat wrapped around nucleic acid
      3. cannot reproduce on their own
    2. reproduction of viruses [Figure 20.13]
      1. lytic cycle
      2. lysogenic cycle

  1. Kingdom Protista

    1. characteristics
      1. structurally most simple eukaryotes
      2. unicellular to multi-cellular
      3. autotrophs and heterotrophs
    2. parasitic molds (fungal-like protists)
      1. chytids, water molds, slime molds
      2. most are saprobes or parasites
      3. examples
    3. protozoans (animal-like protists)
      1. unicellular
      2. heterotrophs
      3. parasitic types produce cysts
      4. may be amoeboid or ciliated
      5. examples
    4. sporozoans (animal-like protists)
      1. parasitic protists that complete part of their life cycle in a specific host
      2. many cause disease
      3. examples
    5. algae (plant-like protists)
      1. unicellular to multi-cellular
      2. photosynthetic autotrophs
      3. examples

    2.  

    © Carol L. Wymer, 2003