exam #2

• Kingdom Fungi Characteristics


  • All are eukaryotic
  • All are heterotrophic and absorb nutrients
  • All possess cell walls of chitin
  • All are non-motile
  • Reproduce via spores
  • They exist as haploid adults
• Types of heterotrophic fungi - Free Living

  • Saprotrophic - Feed off dead or decaying organisms, decomposers
• Saprotrophic fungi


  Release acids and enzymes that break down tissue into smaller molecules they can absorb
• Types of heterotrophic fungi - Symbioses

  • Mutualistic - Both species benefit from the relationship
  • Parasitic / pathogenic - Fungi will infect the host and cause disease or death
• Mutualistic symbiosis - Mycorrhizal


  • Beneficial union with the roots of plants by weaving into the root cells or wrapping around the root themselves
  • Fungi bring in additional moisture, and nutrients
  • Plants give access to carbon sugars from photosynthesis
  • 95% of plants form mycorrhizal partnership with fungi
• Parasitic / pathogenic fungi

  • Caterpillar Fungus (Cordyceps)
  • Athletes Foot/ Ringworm
  • Candida
• Cordyceps fungus


  Develops inside insect larvae, killing and mummifying the remains before popping out as a fruiting body
• General Fungal Anatomy


  • Unicellular fungi - Exists as yeasts, Reproduce via budding
  • Multicellular Fungi - Exists as molds and mushrooms, Reproduce via spores
  • Dimorphic fungi - have the ability to switch between the mold and yeast form
• Unicellular Fungi Reproduce Via Budding

  Budding cells - form of asexual reproduction that results outgrowth from the parent
• Hyphae


  Filamentous cells
• Hyphae


  • Vegetative hyphae - digest and absorb nutrients
  • Reproductive hyphae - produce spores for reproduction
• Mycelium


  Interwoven mass of hyphae that infiltrates the material on which the fungus feeds (grows rapidly)
• Fruiting Body


  Reproductive structure that creates spores (asexually or sexually created)
• Asexual Reproduction


  1. Reproductive hyphae and spores grow directly from a single hyphal strand and create genetically identical spores

  2. Conidiospores (conidia): free spores
• Sexual Reproduction


  1. Two mating hyphal strands meet and fuse creating genetically unique spores

  2. Plasmogamy - sharing of cytoplasm between two hyphae cells of two different individuals

  3. Heterokaryotic stage - 2 haploid nuclei from different individuals are contained within a cell of structure

  4. Karyogamy - the fusion of nuclei from the two opposite individuals thereby producing a diploid zygote

  5. Meiosis occurs creating haploid spores
• Phyla of Fungi


  • Chytridomycota - Chytrids
  • Ascomycota - Sac and cup fungi
  • Deuteromycota - Imperfect fungi
  • Basidiomycota - Club fungi (mushrooms)
  • Zygomycota - Zygospore forming
• Chytrids


  Unique fungi that create flagellated spores, inhabit aquatic environments, often parasites
• Chytrids


  • Batrachochytrium dendrobatidis - Parasitic fungi responsible for mass extinctions of most amphibians on Earth
• Ascomycota (Ascomycetes)


  • Live in marine, freshwater, and terrestrial habitats
  • Can be unicellular (yeasts) or multicellular (commonly called sac or cup fungi)
  • Include plant pathogens, decomposers, and symbionts
  • More than 25% of all ascomycete species form symbiotic associations with green algae or cyanobacteria called lichens
• Ascomycota


  • Saccharomyces cerevisiae - Baker's Yeast
  • Morchella - Sac Fungi
  • Peziza - Cup Fungi
• Saccharomyces cerevisiae


  Unicellular Fungi, Reproduces via budding, Facultative anaerobe - produces CO2 and ethanol, Used in baking and brewing, Exclusively domesticated species because of its scarcity in natural environments
• Morchella


  Multicellular Sac Fungi, Some species are saprotrophic and form facultative mycorrhizal-like associations with plant roots, High economic value because of their unique taste and rich nutritional value
• Peziza


  Multicellular Cup Fungi, Saprophytic fungi that grow on the ground, rotting wood, or dung, Most not edible, Around 100 species of the genera are known
• Asexual Reproduction in Ascomycota

  Mycelia produce large numbers of conidia, Asexual spores produced externally (not in a sac) in long chains and dispersed by the wind
• Sexual Reproduction in Ascomycota

  1. Plasmogamy creates a dikaryotic ascus (spore producing sac)

  2. Karyogamy creates a diploid nucleus

  3. Diploid nucleus undergoes meiosis followed by mitosis to produce 8 haploid ascospores in each ascus

  4. Ascocarp (entire fruiting body) begins to form around all of the asci

  5. The asci rupture and release the ascospores
• Ascomycota - Peziza


  • Lifecycle showing asexual and sexual reproduction
• Lichens


  • A mutualistic relationship between an ascomycete fungus and either red or green algae
  • Fungi absorb nutrients and water for algal cells
  • Algae provide glucose to fungal cells
• Variation in lichen growth forms

  • Fruticose - "shrub-like" lichens, Foliose - "leaf-like" lichens, Crustose - "crust-like" lichens
• Lichens were on land 420 million years ago; these early lichens may have modified rocks and soil much as they do today, helping pave the way for plants
• Deuteromycota - Imperfect Fungi

  • Exist as molds or multicellular filamentous fungi that form visible mycelia - furry carpets of growth - cottony, hairy, or velvety texture
  • Only reproduce asexually - "Imperfect" since a sexual life cycle is unknown or absent
• Deuteromycota - Imperfect Fungi

  • Penicillium notatum - Found world-wide, in soil, decaying vegetation, air, One of the most common causes of spoilage of fruits and vegetables, Produced the first ever known modern antibiotic discovered by Sir Alexander Fleming in 1928
• Fruticose lichens


  • Shrub-like, grow in the tundra and is a major food source for reindeer and caribou
• Foliose lichens


  • Leaf-like, commonly found on branches of wetland trees
• Crustose lichens


  • Crust-like, commonly found on the bark of trees
• Lichens


  • Foliose (leaflike)
  • Fruticose (shrublike)
  • Crustose (encrusting)
• Lichens are important pioneers on new rock and soil surfaces
• Molds


  Microscopic reproductive structures, only reproduce asexually - "Imperfect" since a sexual life cycle is unknown or absent
• Multicellular filamentous fungi


  Form visible mycelia - furry carpets of growth - cottony, hairy, or velvety texture
• Deuteromycota


  Imperfect Fungi
• Penicillium notatum


  • Found world-wide, in soil, decaying vegetation, air
  • One of the most common causes of spoilage of fruits and vegetables
  • Saved millions of lives by producing the first ever known modern antibiotic discovered by Sir Alexander Fleming in 1928
  • The spores can trigger allergic reactions in individuals sensitive to molds