Fungi – Microbiology Test Questions – Flashcards
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Symbiosis |
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Close association between two different types of organisms |
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Mutualism |
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Relationship in which members of two different species benefit and neither suffers from association |
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Commensalism |
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Relationship in which one species gains some benefit while the other species has no advantage |
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Saprobes, Saprobic, Saphrobic |
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term for organism that feeds on dead organic matter; most of fungi are saprobic |
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Parasitism |
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One species of the association benefits while the other is harmed |
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Mitochondria |
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with flattened cristae; oomycetes have mitochondria with chloroplasts |
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retronemes |
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hollow tube hairs on the ends of flagella on oomycetes |
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oomycetes |
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are fungi with small "f" but because of retronemes and they have ameboid pseudopodial stage; they are also social like protozoa; heterotrophic |
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achlorophyllous |
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cannot photosynthesize |
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yeasts |
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encapsulated and unicellular |
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molds |
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filamentous and multicellular |
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cell wall |
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chitin & beta-glucans; chlorophytes and other fungus-like but not Fungi orgs have cellulose |
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osmotrophic |
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absorptive - because of chitin in cell wall, cannot phagocytize; plants are photosynthetic, animals are phagotrophic |
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How are fungi main players? |
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they are the main contributors of carbon to terrestrial environment. w/o Carbon, it would be 100 years left of photosynthesis |
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Four Fungi Phylum (based on reproduction stage) |
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Ascomycetes, Basidiomycetes, Zygomycetes, Chytridiomycetes |
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facultative lifecycle |
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The fungi is directed by the environment - choose best mode for survival; bad environment would direct sexual; good environment would direct asexual. Both stages morphologically distinct. |
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Eukaryote Phylogeny |
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Fungi still eukaryote but because they live w/i host & absorb nutrients, they are Fungi Kingdom. |
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Radical Invention |
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Cavelier-Smith found that Fungi have chitinous cell wall and absorb nutrients. Originally thought they were pre-ancestral flagellates that phagocytized w/ loricae made of chitin. |
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Translocation |
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allows for searching of nutrients in other areas if current environment lacking; filaments are very robust (unlike bacteria); can go through substrate. |
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Chemotropism |
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one-sided attraction to food source (no gradient like chemotaxis) |
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Zygomycota |
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Zygomycetes (derived from Chytrids) Coenocytic hyphae with septa only where reproductive cells are formed; form asexual sporangiospores; Zygosporangium is one big structure, like a sac, holding zygospores |
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Ascomycota |
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Ascomycetes; sac fungi; septic hyphae in mycelium; asexual reproduction leads to formation of conidiospores; ascospores on inside of sac but outside of fungi; even number of spores because meiosis; sexual & asexual (holomorphs) |
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Basidiomycota |
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Basidiomycetes; Have a basidium & basidiospores; spores on outside; sexual & asexual (holomorphs) |
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Chytridiomycota |
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Oldest known fungi; "chytrids"; zoospores; flagella w/o retronemes |
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Ascus |
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saclike reproductive structure |
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Basidium |
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reproductive structure on which sexual spores are produced after hyphal fusion; spores don't mature inside mushroom - they do it outside in the gills |
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Chytridiomycetes |
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"Chytrids"; only fungi w/ flagella but no retronemes |
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Deuteromycetes |
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anamorphic because no known sexual stage; might never have had it or lost it along the way; "mitosporic fungi" |
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Mitosporic fungi |
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deuteromycetes - no known sexual stage; asexual state; parasexuality; some of most frequently encountered fungi; ascomycetes ; basidiomycetes; produce conidia - identified by development, morphology ; conidiogenous cell ; conidia |
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Zoospores |
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oomycetes, not true Fungi; zoospores allow them to live in wet environment; fungi with small "f" |
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Mycetozoans |
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fungi-like protozoans that are motile; only resemble fungus in morphology Acellular slime molds: like separated slugs; form structures to protect selves when nutrients limited; were myxomycetes; one big cell w/ millions of nuclei cellular slime molds: amoeba joined together to form one signal to sporylate protozoa |
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Thallophytes |
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plants w/o stems, roots or leaves; very filamentous and simple (like algae) |
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Thallus |
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vegetative body of thallophyte; used to designate somatic organization of fungus |
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Hyphae |
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long branched filaments used by mold |
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Mycelium |
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thick mass of intertwined hyphae |
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Mycoses |
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term for diseases caused by fungi |
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Haustoria |
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plant-pathogenic specialized hyphae that invade plant cell walls |
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Septic Hyphae |
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Basidiomycetes ; Ascomycetes; have crosswalls; control of water balance so live in dry conditions. 2-4 microns |
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Aseptic Hyphae |
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Zygomycetes; no crosswalls; no control of water balance; live in damp conditions bcz of lack of water control; Can be up to 10 microns |
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mycology |
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study of fungi |
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dimorphic |
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alternate between unicellular and multicellular |
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Zygomycetes |
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Aseptate hyphae; sexual cycle |
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Rhizomorph |
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go on path of least resistance in search of nutrients; can spread out through substrate to look for food; macroscopic - mushroom like |
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Stroma |
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protection to spore-producing part of fungi; balled up mycelium (tissue) to elevate fungi to spread spores better; macroscopic; only part of fungi that can be grown in lab with right conditions (cannot do plants/animals) |
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Microfungi |
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Requires microscope to view; Molds ; Yeast |
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Macrofungi |
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Mushrooms, toadstools, basidiomycetes ; ascomycetes; visible to naked eye |
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Meiosis |
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sexual stage |
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Mitosis |
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asexual stage - form asexual spores |
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Sexual Stage |
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Teleomorph ; Perfect Stage; can be used for protection ; survival. Only one stage |
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Asexual Stage |
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Anamorph ; Imperfect Stage; zillions of spores can be released. This classification is used in biomedical mycology; can have several dozen asexual stages but still same organism. |
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Pleomorphic |
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fungi can switch between sexual and asexual stages based on the need and environment; morphologically different and occur at different times and places (rarely at same time); one species can form several types of spores |
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Nomenclature problems |
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Because fungi doesn't have 1 specific sexual state; cannot determine naming convention |
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Holomorph |
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Whole fungus - sexual & asexual states |
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Teleomorph |
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sexual state "perfect state" |
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Anamorph |
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asexual state "imperfect state"; also mitosporic state |
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Plasmogamy |
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union of two protoplasts |
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Karyogamy |
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fusion of two nuclei --> diploid stage |
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Dikaryotic Stage |
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two cells that have fused with their own nuclei to create one cell with two nuclei |
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Haploid Restoration |
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meiosis occurs after reproduction stages to restore haploid stage |
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Nuclear Cycle |
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haploid or diploid |
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Parasexuality |
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Heterokaryosis; expression of multiple phenotypes; a lot of asexual fungi can have this (plasmogamy); appearance of sexuality - rearranged phenotype Expression of different types of nuclei at same time w/i mycelium mass |
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Ascocarp |
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fungal structure of tissue; naked asci; Cleistothecia is closed, hollow sphere Perithecia: flask-like Apothecia: cup or disk-like with stalk |
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Basidiocarps |
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spores are released from gills under caps; these can be very lethal to small animals colors of spores can determine species and genera (white, lilac, pink, black, etc); dead air w/i crevices where spores stored until released by wind, water, etc |
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Zygosporangia |
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Red ball structures with zygospores inside two mating types (+, -) with suspensors that are held up by stalks; they come together and reproduce |
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Zygosporangia Suspensors |
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depending on stage or situation, suspensors can have different morphologies |
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Conidia |
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asexual spores from mitosporic fungi (conidium singular); almost always ascomycetes or basidiomycetes; long chains allow for conidia to be dispersed by wind; hyphae are under surface medium or host |
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Hyphomycetes |
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Mitosporic fungi; most common; conidia produced on exposed conidiophores |
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Agonomycetes |
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Mitosporic fungi; mycelial forms that are sterile but produce differentiated vegetative structures; cannot germinate or produce spores so unidentified; not morphologically distinct; 2 types: chlamydospores, sclerotia |
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chlamydospores |
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large, round cell w/ thick wall; survival stage w/o sexual stage |
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sclerotia |
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dense, compact masses of hyphae & mycelium that survive in very low temps and are hard, dark pigmented structure; some form on wheat w/ alkaloids |
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Coelomycetes |
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Mitosporic fungi; produce conidia in conidiomata; mainly in plants, plant pathogens; spores not out in open; plant-related saprotrophs |
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Conidiomata |
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asexual cavities w/ conidiospores lining w/i; not out in open; grow on plants or plants on dead wood |
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Aerial Hyphae |
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part of hyphae on conidiophore that is above substrate or surface and extends up to allow better spreading of conidia (spores) |
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Chytridiomycotina |
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Have zoospores (motile); single flagella; zygote as resting spore resembles zygomycetes; in moist environment - aquatic or terrestrial; saprotrophs or parasites; coencytic thallus |
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Fungal Physiology Characteristics |
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Chemoorganotrophs; osmotrophic; parasites use exoenzymes to attack & break down substrates & also help metabolize |
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Exoenzymes |
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used to attack & break down substrate when cannot get things into cell wall; yeast does not need because they reside in rotting foods with simple sugars that quickly absorb |
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Primary Metabolite |
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compound with known metabolic function |
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Secondary Metabolite |
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compound w/o known function; most medically necessary things from secondary; growth stopped but can still produce compounds for medical or industrial purposes |
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Major Secondary Metabolites |
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Terpenes, Carotenoids, Steroids, Antibiotics |
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Secondary Metabolism |
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Waste products, reserve storage food, safety-valve shunts, specialized functions: chelators, hormones, antibiotics; carbon-nitrogen ratio can be balanced out with this |
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Fungal Ecology |
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Major moderators of carbon cycle; have to degrade lignin to get to cellulose (more complex) so CO2 can be released; most organisms cannot break lignin; brown wood rotting fungi |
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Lignin |
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protects polysaccharides from enzymatic digestion; oxidative process; not primary carbon source |
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Cellulose |
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Complex; needed for primary carbon source |
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Lichen |
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association of fungus and algae - two organisms intertwined to form what looks like individual organism; fungus responsible for nutrients, algae has photosynthesis and returns other nutrients to fungus |
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Mycorrhiza, Mycorrhizae |
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association between hyphae of certain fungi & absorptive organs of plants; spread out into substrate or soil & bring in nutrients; fungus makes plants more competitive; 30% of plants have association |
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Pioneer Organisms |
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Lichens; can live where others cannot; they start process of soil formation & produce acids that decompose minerals of rocks, allow for other organisms can come in; has maculae, medulla, upper/lower cortex, algal layer, rhizine |
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Lichen |
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always fungi & algae |
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Metabolism |
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primary or secondary metabolites |
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primary metabolites |
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known function = biproducts that are made and can be used for later chemical functions |
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secondary metabolites |
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no known function = waste products not needed but can be used by other organisms (antibiotics, steroids) |
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Why are exoenzymes needed? |
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from outside cell to help fungi absorb nutrients |
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microalgae |
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thallophyte |
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vegetative state of fungi |
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thallus |
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phylogenetically heterogenous but similar in characteristics |
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oomycetes & mycomycetes |
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one-sided attraction to nutrients |
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chemotropism |