01:119:116 Lecture Notes - Lecture 4: Unikont, Nucleariida, Dikaryon
27 Aug 2019
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Outcomes: sequence the basic sexual & asexual lifecyles of a fungus. I the evolution of fungi: origin of fungi. Sister group to the nucleariids: colonization of land. ~ 100,000 species named 5 major groups within the fungi. Characteristics of fungi: mostly haploid life cycle, no photosynthesis , heterotrophs - digests externally. Same substance that insects use in exoskeletons. Wet, moist, nutritious: body structure, single cell = yeasts only. Or: multicellular (many cells) , mycelium (pl. mycelia) Grows in and around food source: hyphae - long branched filaments, specialized hyphae. But can be: predatory, mutualistic like the haustoria found in mycorrhizae, reproductive. Aerial hyphae - aids in spore dispersal. A single-cell - starts a new individual. # of mating types depends on # of alleles: two haploid (n) fungi. Hyphae release pheromones & test compatibility: fuse cell membranes (n+n) cell. They grow and fuse to each other. Two different nuclei in the same cell. Plasmogamy = fusing cytoplasm to form heterokaryon.
