April 25

Eukaryotic Diversity

Eukaryotic Diversity

Diplomonads

  • Unicellular, flagellated protists
  • Lack mitochondria and chloroplasts
  • Live in anoxic habitats
    • Animal intestines
  • Conserve energy from fermentation
  • Can cause diseases in:
    • Fish
    • Domestic animals
    • Humans
  • Contain two nuclei of equal size
  • Contain mitosomes
  • Reduced mitochondria lacking electron transport proteins
  • Genome quite compact
    • Contains few introns in genome
  • Lacks genes for metabolic pathways such as the citric acid cycle

Euglenozoans

  • Unicellular
  • Can be free-living or parasitic flagellated
    • Kinetoplastids and euglenids
  • Kinetoplastids
    • Kinteoplast
      • Mass of DNA present in single, large mitochondrion
    • Primarily live in aquatic habitats
    • Some are parasites of animals and humans
    • Responsible for Trypanosoma cells
      • Trypanosoma brucei causes African sleeping sickness, which is a chronic and fatal disease
      • Trypanosoma cruzi causes Chagas disease
        • Spreads by a “kissing bug”
        • Can be fatal
      • Leishmania causes cutaneous and systemic leishmaniasis
    • Euglenids
      • Motile and nonpatbhogenic
      • Chemotrophic and phototrophic
      • Contain two flagella
        • Dorsal and Ventral
      • Live in aquatic habitats
        • Freshwater and Marine
      • Contain chloroplasts
      • In darkness they can lose chloroplasts and live as cheoorganotrophs
      • Many feed on cells by phagocytosis

Alveolates

  • Contain aveoli
    • Cytoplasmic sacs located under the cytoplasmic membrane
    • Helps cell maintain osmotic balance by controlling water influx and efflux
    • Some function as armor plates
  • Ciliates
    • Contain cilia
      • Function in motility and some cover the cell
      • Paramecium are widely distributed species
    • Have macronuclei and micronuclei
    • Maconucleus
      • Growth and feeding
    • Micronucleus
      • Sexual reproduction
    • Parramecium
      • Hosts for endosybiotic prokaryotes and eukaryotes
    • Obligate anaerobe ciliates
      • Present in rumen of animals
      • Some can be parasites to animals
        • Balatidium coli is an intestinal parasite in animals
      • Dinoflagellates
        • Marine and freshwater phototrophic alveolates
        • Have two flagella of differents lengths and with different points of insertion
          • Transverse and longitudinal insertion points
        • Some are free-living and some share symbiotic relationships with coral reefs
        • Some are toxic
          • Gonyaulax cells or red tides
            • Kills fish and poisons humans
          • Pfiesteria
            • Infect and kill fish due to neurotoxins that affect movement and destroy skin
          • Apicomplexans
            • Nonphototrophic obligate parasites
            • Can cuase malaria, toxoplasmosis, and coccidiosis
            • Nonmotile adult stages
            • Produce sporozoites
              • Function in transmission of the parasite to a new host
            • Apicoplasts
              • Dengenerate chloroplasts that lack pigments and phototophic capacity
              • Catalyze fatty acid, isoprenoidm and heme biosynthesis and export products to cytoplasm

 

Stramenophiles

  • Contain chemoorganotrophic and phototrophic microorganisms and macroorganisms
  • Possess flagella
    • Diatoms
      • Unicellular
      • Phototrophic
      • Major component of plankton
      • Produce cell wall made of silica
        • Protects cell against predation
      • Diatom Frustule
        • Resistant to decay
      • Oomycetes
        • Water molds
          • Contain flagellated cells
        • Coenocytic hyphae
        • Cell walls are made of cellulose
        • Phytophthora infestans
          • Causes blight disease of potatoes
        • Pythium
          • Causes white rust of agricultural crops
        • Golden algae
          • Chrysophytes
          • Primarily unicellular marine and freshwater phototrophs
          • Two flagella
          • Chlorophyll c major pigment
        • Brown algae
          • Marine and multicellular
          • Typically macroscopic
          • No unicellular brown algae
          • Seaweeds are considered brown algae

Cercozoans

  • Chlorarachniophytes
    • Freshwater and marine amoeba-like phototrophs
    • Develop a flagellum for dispersal
    • Acquisition of green algal chloroplasts is a prime example of secondary endosymbiosis
  • Foraminifera
    • Exclusively marine and form shell-like structures called tests
      • Tests are organic materials reinforced with calcium carbonate
    • Hosts a variety of algae that form endosymbiotic relationships with the protists
    • Tests are resistant to decay and readily fossilized

 

Radiolarians

  • Mostly planktonic marine eukaryotes
  • Form threadlike pseudopodia
  • Strictly heterotrophic
  • Reside in the upper 100m or so of ocean waters
  • Consume bacteria and particulate organic matter
  • Some associate with algae that take on a symbiotic role and supply nutrients to the radiolarian
  • Tests have radial symmetry

Amoebozoa

  • Terrestrial and aquatic protists
  • Lobe-shaped pseudopodia for movement and feeding
  • Gymnamoebas
    • Free-living protists
    • Live in aquatic and soil environments
    • Amoeboid movement
      • Facilitates pseudopodia movement
    • Amoeba
      • Common organism in pond waters
    • Entamoebas
      • Parasites of vertebrates and invertebrates
      • Live in oral or intestinal tract of humans
      • Entamoeba histolytica
        • Pathogenic to humans and cause amebic dysentery
        • Forms cyst
      • Slime molds
        • Motile
        • Plasmodial slime molds
          • Vegetative form are masses of protoplasm
        • Cellular slime molds
          • Vegetative form are single amoebae
        • Live primarily on decaying plant matter
        • Form differentiated spore-like structures that can remain dormant and then germinate

 

Chytridiomycetes

  • Earliest diverging lineage of fungi
  • Fruiting body contains sexual spores
    • Flagellated and motile
  • Some exists as single cells whereas others form colonies with hyphae
  • Batrachochytrium dendrobatidis
    • Causes chytridiomycosis of frogs
  • Some are obligate anaerobes
  • Inhabit rumen of ruminant animals
  • Neocallimasitx
    • Inhabits the rumen and conserves energy from the fermentation of sugars to acids

Zygomycetes

  • Known for food spoilage
  • Found in soil and on decaying plant material
  • Rhizopus
    • Black bread mold
    • Undergoes asexual and sexual reproduction

Glomeromycetes

  • Important in mycorrhizal associations
  • Form symbiotic relationship with plant roots
  • Relatively small
  • Obligately symbiotic and all species form relations with endomycorrhizae
  • Played pivotal role in early vascular plants ability to colonize on land
  • Reproduce asexually and are coencytic

Ascomycetes

  • Single-celled species
    • Saccharomyces (Baker’s yeast)
  • Common mold
    • Aspergillus
  • Found in aquatic and terrestrial environments
  • Reproduce asexually by production of conidia that form at tips of specialized hyphae
  • Saccharomyces
    • Reproduce sexually in which two cells fuse, zygote

 

 

 

Basidiomycetes

  • Basidium
    • Structure in which haploid basidiospores are formed by meiosis
    • Basidiocarp
      • Mushroom fruiting body
      • Starts out as mycelium that differentiates into a small button-shaped structure underground that then expands into the full-grown basidiocarp
    • Diakaryotic basdia
      • Borne on the underside of the basdiocarp on flat plates called gills, which are attached to the cap of the mushroom

 

Algae

  • Red Algae
    • Rhodophytes
    • Inhabit marine environment
    • Few species found in freshwater and terrestrial habitat
    • Phototrophic and contain chlorophyll a
    • Chloroplasts contain phycobiliproteins
      • Major light harvesting pigments of cyanobacteria
    • Red color results from phycoerythrin
    • Most species are multicellular
    • Lack flagella
    • Some are filamentous, leafy, or coralline in structure
    • Unicellular
      • Cyaniadiales
        • Live in acidic hot springs at temperatures and at pH values 0.5 to 4.0
      • Green Algae
        • Chlorophytes
        • Conatain chlorophylls a and b
        • Lack phycobiliproteins
        • Chlorophytes and charophyceans
        • Chlorophytes
          • Unicellular and multicellular species
          • Volvox(colonial level)
            • Forms colonies composed of several hundred flagellated cells
              • Some are motile and carry out photosynthesis
              • Some specialize in reproduction
            • Cells are interconnected by thin strands of cytoplasm that allow the entire colony to swim in a coordinated fashion
          • Some green algae have potential for biofuels
          • Endolithic
            • Some grow inside of rocks
              • Cold and dry environments


Posted April 25, 2017 by andrew in category Learning Summary

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