BIOL 211 Lecture Notes - Lecture 9: Karyogamy, Ascus, Dikaryon
6 Oct 2017
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Single celled or filamentous with cell walls made of chitin. Some species of chytrids are parasites of amphibians> may be involved in worldwide decline in amphibian population. Contains many 2n zygotes> each will undergo meiosis to produce 4 1n spores. Sporangium> produces haploid spores by mitosis for asexual reproduction. 80% of all plants have mycorrhizal relationships with members of this lineage. Roots of almost all vascular plant species form mycorrhizal relationships> very important in allowing plants to accumulate mineral nutrients. Dikaryotic cells are produced during sexual reproduction> two haploid nuclei in each cell for a portion of the life cycle because plasmogamy (fusion of cytoplasm) has occurred but karyogamy (fusion of nuclei) has not. Meiosis occurs inside of basidia to form 4 basidiospores. Asexual reproductive spores not produced by most species. (cid:373)ale a(cid:374)d fe(cid:373)ale do(cid:374) t really apply> ge(cid:374)eti(cid:272)ally (cid:271)ut (cid:374)ot (cid:373)orphologi(cid:272)ally disti(cid:374)(cid:272)t (cid:862)(cid:373)ati(cid:374)g types(cid:863) Zygote is only 2n cell in the life cycle.
