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Unformatted text preview: Exam 2 • (fig. 31.2) Kingdom Fungi o Eukaryotic, multicellular cells o No chlorophyll, but do send out exoenzymes to digest their materials outside of the cell o Heterotroph – absorptive by digesting organic material outside then ingest o Different in their structures o Saprobes – scavengers on dead living organisms (white stuff on dead stuff) o Parasitic – survive on living host; many plant losses in agriculture are due to parasitic fungi o (fig. 31.22) Symbiotic relationship with Ants and Fungi – leaf cutter ants cut out half-moon leaf – carry the leaves back to nest and harvest the fungi; a mutualistic relationship; remember the michorrizae o Hyphae structure – many hyphae = mycelium – structural support in anchoring o (fig. 31.4) Parasitic fungus stick its Haustorum into the host cells, sends out its enzymes to break down the cell, and then sucks all the cytoplasmic fluid out. o (fig. 31.3) Structure of Hyphae Septa Hypha – separate cells; spaces between each individual cell and nuclei for each cell Coenocytic Hypha – multiple nuclei Dikaryon/heterokaryon = 2 nuclei/multiple nuclei o Fungi are haploid (n) o Asexual mostly but sexual under stress; Basidiomycota are almost always sexual reproducers o (fig. 31.5) Generalized life cycle of fungi Sexual • Mycelium plasmogamy(fusion of cytoplasm) heterokarytotic stage karyogamy(fusion of nuclei) zygote(2n) meiosis spore-producing structures spores(n) germination mycelium Asexual (completely haploid) • Mycelium – spore producing structures – spores – germination mycelium o (fig. 31.9) Fungal Phyla Chtridiomycota most primitive fungi • motile spores with flagella; only fungal group with spores with flagella • also have chitin in their cell wall • have coenocytic hyphae Zygomycota • Black bread mold • Seldomly mating sexually under stress with mating types not male or female • Resistant zygosporangium as sexual age • (fig. 31.12) Rhizopus (black bread mold) life cycle Ascomycota • (fig. 31.17) Ascomycota Neuroapora life cycle • Sac fungus • Largest group of the fungi and very diverse • Unicellular yeast can be found in this group • Edible morels that grow in association with oak tree • (fig. 31.24) Lichens it can be a green algal or cyanobacteria that benefits from a mutual relationship with fungal hyphae • Ergot – causes severe hallucination/convulsions, death of cells in extremities, the natural occurring form of LSD • Truffles – naturally grow underground, and can be used for French cook; release androstenol (sex hormone); very expensive; used truffle pigs in olden times to locate the underground truffles(female pigs were always better at locating them than males because of the truffles’ releasing of androstenol) • Cause most of the plant diseases; Elm and Chestnut trees were all killed off by Ascomycota in America • Ergot may have been a cause of convulsions/hallucinations in...
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- Spring '08