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Cards In This Set
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How are spores carried long distances?
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Einf, water, if they land in a moist plcae with food they germinate
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The spores of most fungal species are...haploid or diploid?
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Haploid,but some gundi have transient diploid stages that form during their sex life cycles
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How do fungi have sex? How do they start their sexual life cycles?
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Hyphae from two mycelia release pheromones (sexual signal molecules)
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Sex only happens when the mycelia are of differnt mating types, so how?
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The pheromones from each partner bind to receptors on the other, hyphae extend to the source of the pheromones and then they fuse: contributed to genetic variation, preventing hyphae from fusing with other hyphae of same mycelium
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What is plasmogamy?
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The union of the cytoplasms of he two mycelia when the parents meet
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Do the haploid nuclei fuse right away?
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No, at a certain point for a significant part, the fused new mycelium has two genetically different haploid nuclei! This mycelium is called a heterokaryon (when they are in this stage the nuclei can exchange DNA like crossing over)
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Can they stay unfused?
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Yes, they can both pair off into a single cell in some species of fungi, then the mycelium is called dikaryotic (2 nuclei), two nuclei in each cell divide without fusing, DIFFERENT from diploid cells that have pairs of homologous chromosomes within a single nucleus
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So you have Plasmogamy (fusion of cytoplasm), then the heterokaryotic stage (two unfused nuclei), then what comes next...?
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Karyogamy! (this can happen hrs to centuries later after plasmogamy), the haploid nuclei fuse, producing a diploid cell (cells), zygotes form during karyogamy (ONLY DIPLOID STAGEIN MOST FUNGI)
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What happens after this, remain diploid?
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No, meiosis happens, restores the haploid condition, lead to the formation of haploid spores that enable the fungi to disperse
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Does the sexual process of karyogamy and meiosis produce geneticc variation?
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Yes, having a diploid turned haploid produces variation
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So what about Asexual reproduction?
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Many fungi do this! wide variety of how its done among fungi
MOLDS: grow as filamentous fungi that make haploid spres by mitosis , form visible mycelia YEASTS: some fungi reproduce asexually by growing as single-celled yeasts, instead of mitosis, small "bud cells" bud off parent cell |
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What are deuteromycetes?
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Yeasts and filamentous fungi that have no sexual stage
Imperfect fungi |
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Fungi evolved from a...?
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Flagellated ancestor, though majority of fungi don't have flagella, some of the earliest-diverging lineages of fungi DO have flagella, and most of the protists that shhare a close common ancestor with animals and fungi ALSO have flagella
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What are opisthokonts?
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Well DNA sequence data says that three grps of eukaryotes (fundi, animals, protist relatives) form a clade that is called this, because they came from flagellated ancestors
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How do you know that fungi ancestor was unicellular?
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Use DNA sequencing to figure out that fungi are more closely related to several grps of single-celled protists than they are to other opisthokonts, so that thheir ancestor is single celled
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