Chapter 31 - BSC 1010 Dr. Presley Chapter 31 KINGDOM FUNGI...

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BSC 1010 Dr. Presley Chapter 31 KINGDOM FUNGI GENERAL CHARACTERISTICS - fungi and animals are descended from common ancestor - unicellular(yeasts), coenocytic (non-septate), to multicellular - eukaryotic - cell wall contains chitin (polysaccharide) - lacking flagella (except for one small aquatic group - Chytridiomycota) - heterotrophic by absorption (secrete digestive enzymes, absorb nutrients) - saprobes - feeding on dead matter, decompose cellulose and lignin - parasitic - feeding on living matter (facultative or obligate forms) - people with AIDS are susceptible to diseases caused by fungi (pneumonia, diarrhea, candidiasis) - predatory – secrete sticky substance to trap passers-bye - some have constrictive ring to trap worms - mutualistic associations: mycorrhizae – association of fungus and plant root lichens – association of fungus and cyanobacterium or photosynthetic protist - hyphae are tubular filaments - septate (separate cells) or non-septate ( coenocytic ) - cytoplasm flows through pores in cell wall to adjacent cells - Study Figure 31.3 on page 605 - haustoria = parasitic tip of hypha that invades host tissues and surround cells, absorb nutrients from host Fig 31.4, p. 605 - rhizoids – function for anchorage, do NOT absorb nutrients - mycelium = body of fungus made of many hyphae - growth at tips in search of food, can be very large (acres covered) - can persist for years - Study Figure 31.1 on page 617 - fruiting (reproductive) structure = mycelium structure for spore production - glycogen is food reserve - most are haploid - reproduction: haplontic life cycles - asexual by non-flagellated spores, fragmentation, conidia or budding - sexual reproduction: Straight forward method - - haploid hyphae of different mating types fuse at tip - produce diploid nucleus or zygote - undergoes meiosis - release haploid spores Dikaryon method – - haploid hyphae of different mating types fuse plasmogamy = cytoplasms with different nuclei fuse - dikaryon produced (two nuclei of different types in a hypha) = heterokaryon - produce a fruiting structure - fusion of nuclei ( karyogamy ) forming a zygote (diploid) in fruiting structure - meiosis - produces non-motile spores - germinate to form new haploid hyphae *does not require water for fertilization - taxonomy = 4 divisions(also called phyla), Fig. 31.6, p608 - based on sexual reproductive structure Table 31.1, p. 608 DIVISION CHYTRIDIOMYCOTA See Fig. 31.7 on p. 608 - probably resemble common ancestor of all fungi - freshwater, moist soil, few are marine
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This note was uploaded on 03/31/2008 for the course BSC 1010 taught by Professor Presley during the Spring '06 term at Virginia Tech.

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Chapter 31 - BSC 1010 Dr. Presley Chapter 31 KINGDOM FUNGI...

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