Bio--Study Guide 3

Bio--Study Guide 3 - EBIO 1220General Biology, Spring 2008...

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EBIO 1220—General Biology, Spring 2008 Study Guide—Exam 3 Professor Sharon Collinge Chapter 31—Fungi • How many described species of fungi are there? 100,000 • What are the major nutritional roles of fungi? Examples of each? Heterotrophs Obtain C from organic sources Secrete exoenzymes to break down complex molecules Absorb smaller organic molecules Diverse Lifestyles: Saprobic (Decomposers) (S) Parasitic (P) Mutualistic (M) • What are structural components of fungi, including hyphae, haustoria, mycelia? Hyphae- tiny filaments composed of tubular walls surrounding the plasma membrane and cytoplasm of the cells. Form complex network within fungi (P/M/S). Haustoria- Specialized hyphae that can penetrate cell walls of plants (P/M) Mycelia- hyphae form an interwoven mass that surrounds and infiltrates the material on which the fungus feeds. Maximized SA:V. • What are mycorrhizal associations? Mycorrhizae- mutually beneficial relationships between plants and fungi. Endomycorrhizae- Extended hyphae through root cell wall. Ectomycorrhizae- Hyphae form on root surface. • What are the key aspects of the asexual and sexual life cycles of fungi? Sexual : Hyphae release Pheromones Hyphae meet-check compatability-fuse (H) Plasmogamy (hetero) Karyogamy (D) Meiosis then spores produced/dispersed (H)
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Asexual : Spores germinate, form mycelia (H) Mycleia produce spore-producing structures (H) Spores germinate-cycle repeats (H) *Common in molds, yeasts. Plasmogamy and karyogamy: Plasmogamy- union of cytoplasm of the two parent mycelia, Haploid nuclei do not fuse right away. (2 H) Heterokaryon- parts of the mycelia contain coexisting, genetically different nuclei. Karyogamy- Hapoid nuclei fuse producing diploid cells, zygotes form, only stage of diploidity for most fungi. (D) • What kingdom is most closely related to Fungi? Animalia • Know the five phyla of fungi, what are their distinguishing features, the approximate number of species, what nutritional role(s) they play, and be able to recognize or recall examples of species from each phylum. Chytridomycota (Chytrids) - 1000 species Simple Produce flagellated spores (zoospores) S/P in aquatic habitats Diverged earliest in fungal evolution. Ex: Batrachochytrium dendrobatidis - Amphibian Chytrid -Invades amphibian skin, affects exchange of water and oxygen with environment -Primary cause of Amph. Declines/Extinctions. Zygomycota (Zygote) - 1000 species Mostly terrestrial Fruit molds, black bread molds, Sake, tempeh. Ex: Pilobolus Decomposes animal feces, Aims sporangia toward bright light: shoots up to 2m high Cows eat grass, defecate spores
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Glomeromycota (Arbuscular Mycorrhizae)- 160 species Distinct from endomycorrhizae Tiny treelike structures- arbuscules- formed in plant root cell. Ecologically significant- 90% of all plant have symbiotic partnerships with
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This note was uploaded on 10/08/2008 for the course EBIO 1220 taught by Professor Demig-addams during the Spring '07 term at Colorado.

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Bio--Study Guide 3 - EBIO 1220General Biology, Spring 2008...

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