Card Set Information

2011-10-15 22:24:08

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  1. Give an overview of Kingdom Fungi characteristics
    • Heterotrophic extracellular digesters w/ unique enzymes (external digestion)
    • Adapted for maximizing surface area (increased absorption)
    • Many are Saprobes (eating rotten things)
    • Multicellular (except yeast)
    • Do not photosynthesize
    • Cell walls are made of chitin (same as arthropods)
    • Closer to animals than plants
    • Eukaryotic
    • Most are filamentous in structure (hyphae)
    • Can grow in wide range of conditions (eg jam, where bacteria can’t survive)
    • Somatic cells are haploid
    • Reproduce sexually and asexually
  2. Describe ecological, disease, commercial, medicinal, and other aspects of Kingdom Fungi
    • Ecological: diverse enzymes which have the ability to break down lignin, return important elements back to the soil, can decompose just about anything (paint, CDs, jet fuel, drywall mud, etc)
    • Disease: 175 known to cause disease in humans. 5,000+ known to cause disease in plants.
    • Commercial: growers spend $$$ on fungicides. Saccharomyces cerevisiae (brewer’s yeast) important for adult beverages, bread, and baking. Penicillium roqueforti involved in cheese production. Mushrooms eaten as food. Potential for toxic waste cleanup.
    • Medicinal: original antibacterial (penicillin accidently discovered). Cyclosporine used as an immune suppressor during organ transplants.
    • Other: yeasts are important for genetic research (metabolism, molecular genetics, eukaryotic development, etc)
  3. Symbiotic association of kingdom Fungi?
    • Mycorrhizae: 80% of vascular plants rely on mycorrhizae for N2 fixation
    • Lichens: ½ fungi and ½ cyano or algae
  4. Phyla of Kingdom Fungi + classes we need to know.
    • Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota
    • Basidiomycota -> Basidiomycetes, Teliomycetes, and Ustomycetes
    • Basidiomycetes -> Hymenomycetes and Gastromycetes
  5. Information about the hyphae of fungus, incl types
    • Hyphae: branching threads of cells
    • Mycelium: tangled mass of hyphae from a single fungus
    • Aseptate (coencytic) hyphae filaments are like a giant interconnected cell (no walls between)
    • Septate hyphae: individual cell separation can be seen
    • Cytoplasm is shared between cells for yum-yum transfer and exchange
  6. Give general kingdom Fungi reproduction information
    • Produces non-moving spores asexually OR sexually
    • Spores can be blown by the breeze, carried by insects, or propelled into the air mechanically
    • Two types of asexual reproduction. Spores are produced by mitosis in both.
    • Conidia: produced by conidiogenous hyphae (specialized cells that produce spores (conidia) that occur singly or in chains
    • Sporangiospores: made within Sporangia which is attached to the sporangiophore (stalk-like structure).
    • In sexual reproduction spores are made by mixing the genes from two parents, and involves meiosis.
    • Sexually-produced spores are giving special names (ascospores, zygospores, basidiospores)
    • Sexual reproduction always involves…
    • Plasmogamy: fusion of cytoplasms leading to dikaryotic condition (can be long or brief)
    • Karyogamy: fusion of nuclei, forming a diploid nucleus (very brief)
    • Meiosos: immediate reduction of diploid nucleus to four genetically varied haploid nuclei
  7. Zygomycota niches, hyphae, special types of hyphae
    • Niches: Decomposers, parasites, endosymbionts (micorrhizae)
    • Hyphae: Aseptate (coencytic) hyphae
    • Specialized hyphae: stolons (horizontally connecting), sporangiophore (reproduction), rhizoid (anchorage), haustoria (parasitic)
  8. Zygomycota sexual and asexual reproduction
    • Asexual: sporangiospores are produced via mitosis in the sporangia, located at the top of the sporangiophore
    • Sexual: Zygospores are produced via meiosis in the zygosporangia. Occurs when 2 compatible mating types are within range of eachother.
    • Gametangia – gamete producing structures which spatially organize the haploid nuclei prior to karyogamy, and perform plasmogamy
    • Mating type – genetically differentiated mating strains
  9. Ascomycota types, hyphae
    • Largest collection of species (30,000+)
    • Types: Mold, powdery mildew (cause blights and rots), yeast, morels, truffles, parasites
    • Hyphae: septate hyphae
  10. Scientific names + info for truffles, yeast, and others listed in Ascomycota handout.
    • Tuber melanosporum: (truffles) – highly prized in gourmet food industry. Worth up to $600/kg (2.2lbs). Collected with help of pig or dog (can smell) because truffles produce scent which is similar to female sex pheromone in pigs.
    • Saccharomyces cerevisiae: (yeast) vast commercial and research applications
    • Aspergillus niger: used to produce citric acid in sodas
    • Aspergillus oryzae: used to make soy sauce/paste
    • Caviceps purpurea: causes ergot in wheat/barley. Ergotized grain contains toxic chemicals including a precursor chemical to LSD. Consuming this grain can result in hallucinations, cramps, convulsions, and death.
    • Chestnut blight: causes a disease known to have been responsible for killing at least 3.5 billion American chestnuts of the Eastern deciduous forests
    • Penicillium: used to age cheese
    • Dutch Elm Disease: causes death in elms, extremely virulent.
  11. Ascomycota sexual and asexual reproduction
    • Asexual: conidia (multinucleated) are formed via mitosis externally by conidiogenous cells which are at the tips of conidiophores (modified hyphae).
    • Sexual: Asci form within the fruiting body known as an ascoma (or ascocarp). Both karyogamy and meisosis occur within the asci, producing 8 ascospores
    • Ascoma can have 3 shapes: cleistothecium (complete enclosed), perithecium (small pore at top), or apothecium (cup shaped)
    • Asci usually develop on an inner surface of the ascoma called the hymenial layer.
  12. Basidiomycota types, hyphae
    • Very diverse phylum, 22,000+ species
    • Basidiomycetes – Hymenomycetes: Mushrooms, coral fungi, tooth fungi, shelf fungi
    • Basidiomycetes – Gastromycetes: Puffballs earthstars, stinkhorns, false puffballs, bird’s nest fungi
    • Teliomycetes: rusts – bright colors
    • Ustomycetes: smuts – look like ash
    • Hyphae: Septate hyphae that include parenthosomes around each perforation
  13. Basidiomycota sexual reproduction
    • Lack unique asexual structures, so sexual is the focus
    • For class Basidiomycetes…
    • 1. Haploid basidiospores germinate and form monokaryotic mycelium
    • 2. Different mating types undergo plasmogamy and create a dikaryotic mycelium
    • 3. Regions of the dikaryotic mycelium enlarge and form a basidiomata (usually in response to light and low CO2)
    • 4. Karyogamy occurs withing basidia (found inside gill of basidiomata), creating diploid zygote
    • 5. Basidiospores (connected to basidium by sterigma) are formed AFTER meosis occurs
    • For classes Teliomycetes and Ustomycetes…
    • No basidioma, spores are produced in masses called sori (singular sorus)
    • Still form basidia and basidiospores.
    • Class Teliomycetes have incredibly complex life cycles with multiple hosts (eg Puccina graminis)
    • Class Ustomycetes produce dusty masses of teliospores. Typically produce large swelling due to internal mycelium growth. Only need on host in their life cycles.
  14. Describe class Basidiomycetes
    • Hymenomycetes: have distinct fertile layer (hymenial layer) where basidiospores are produced. This layer is exposed to the environment BEFORE the spores mature.
    • Psiocybe mexicana is structurally similar to LSD, used in religious ceremonies. Prior to 1960s studies showed LSD may help personality disorders.
    • Gastromycetes: No distinguishable hymenial layer. Basidioma have distinct outer periderm which causes INTERNAL spore maturation. This layer either ruptures or opens naturally once the basidiospores are mature.
  15. General information about yeasts
    • Single celled fungus
    • Primary mode of reproduction is budding, can sexual reproduce (ascospores)
    • Most are Ascomyecetes
    • Used for bread, alcohol, baking, and genetic research
  16. Information about Conidial fungi + commercial importance
    • Used to be called Deuteromycetes
    • Grab-bag of ~15,000 species
    • Sexual lifecycle is absent or unknown. However some members are known, but classified into this category based on strong similarities with other members.
    • Aspergillus – helps produce soy sauce
    • Penicillium roqueforti – helps create many cheeses (Danish blue, Gorgonzola, Stilton)
  17. Information about Lichens (a lot)
    • ½ fungi (usually ascomycetes) and ½ cyano or algae
    • Capable of both photosynthesis and decomposition.
    • Able to live in extremely varied environments
    • Reproduction by simple fragmentation and soredia (algal cells + fungal cells already) dispersal
    • Key to longevity is suspended animation which occurs when they are dry
    • Important aspects…
    • Ecological pioneers – set up environment for other organisms
    • Lichens containing cyanobacteria may help with N2 fixation
    • Great pollution indicators because they cannot excrete chemicals that they absorb from their surroundings. Extensively used to monitor toxic air pollutants such as sulfur dioxide
    • Three types…
    • Crustose: flat/crusty
    • Foliose: leaflike
    • Fruticose: tall and shrublike
  18. Information about Mycorrhizae
    • Benefit plant by increasing absorption of phosphorus, zinc, manganese, and copper
    • Fungi benefit by receives carbohydrates and vitamins from the host
    • Endomycorrhizae: penetrate root cells. Hyphae penetrate root tissue cells forming highly branched structures called arbuscules and occasionally swellings called vesicles.
    • Arbuscules – associate w/ plasma membranes and are thought to aid transfer of materials between environment and cells by increasing surface area
    • Ectomycorrhizae: surround the roots. A highly branched network of hyphae (Hartig Net) forms around the root epidermal and cortex cells.