Ebio 1220 Exam 3 Notes

Ebio 1220 Exam 3 Notes - Ebio 1220 Exam 3 Notes...

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Ebio 1220 Exam 3 Notes 05/03/2008 14:56:00 Sharon.collinge@colorado.edu     100,000 species of fungi have been described possibly 1.5 million? Famous fungi-athlete’s foot-spidermophyton floccosum “Humongous fungus”:2200 acres Armilaria ostoyae potato blight-phytophthora infestans Fungi Nutrition Fungi are heterotrophs Obtain carbon from organic sources Secrete exoenzymes to break down complex molecules Absorb smaller organic molecules Diverse lifestyles: o Saprobic(decomposers) o Parasitic(feed off of living organisms) o Mutualistic(engage in positive relationships) Tuber melanosporum: truffle Hyphae:tubular cell walls, surround plasma membrane and cytoplasm o Extend into soil where they get nutrients needed to grow o High surface area to volume ration of mycelia enhances feeding  efficiency Spore-producing structures-end of hyphae, reproduction taking place
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Reproductive structures”fruiting bodies”- Mycelium(interwoven mass of hyphae)-mass of hyphae strung together Specialized hyphae o To trap and kill prey o To penetrate host tissues(“haustoria”)-hypae that can go into host  tissue, parasitic fungi, or in mutualistic fungi o Parasitic fungi o Mutualistic fungi: mycorrhizae(“fungus roots”) Ectomycorrhizae: hyphae form on root surface Endomycorrhizae: extend hyphae through root cell wall Mycorrhizal associations:  o Mutualism(+/+): Plant obtain nutrients(phosphorus, nitrogen, minerals) Fungus obtains organic compounds(photosynthate) Reproduction of fungi Reproductive cells are spores Nuclei and spores of fungi are haploid o Haploid-one copy of each chromosome Diploid stage is transient(doesn’t last very long) o Diploid-two copies of each chromosome Generalized fungal life cycle Sexual life cycle-spores floating around in air, germinate(under go cell  division to form mycelia) those mycelium get to time to reproduce and if they  are different enough genetically they fuse cytoplasm called plasmogamy  which produces heterokaryotic stage(cytoplasm fused but not nuclei) then  karyogamy(fusion of nuclei) and produce zygote(diploid phase) then zygote  undergoes meiosis and produces haploid spore producing structures then  produces spores then cycle repeats. 
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Asexual cycle-spores produced, germinate, form mycelia which produce more  sporm producing structures then repeat, no union of nuclei to form diploid  zygote Generalize sexual life cycle in words Sexual reproduction:  o Hyphae from 2 distinct mycelia emit phermones o If different mating types, hyphae will fuse o Union of cytoplasm is called plasmogamy o Mycelia are now heterokaryotic(“different nuclei”)
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This note was uploaded on 05/02/2008 for the course EBIO 1220 taught by Professor Demig-addams during the Spring '07 term at Colorado.

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Ebio 1220 Exam 3 Notes - Ebio 1220 Exam 3 Notes...

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