Unformatted text preview:

Chapter 22 Opisthokants:group of fungi,animals, and choanoflagellates modes of nutrition◦ Saprobes:absorb nutrients from dead organic matter◦ Parasites:absorb nuterients from living hosts◦ Mutualists:benefit both partners fungi evolved from unicellular protist that had falgellum Unicellular,free-living fungi are yeasts Body of multicellular fungi=mycelium◦ composed of individal tubular filaments (hyphae)▪ hyphae subdivided into cell-like ocmpartments by incomplete cross-walls=septa▪ other species have hundreds of nuclei=coenocytic and no septa  Fungi have tolerance for highly hypertonic environmental Saprobic fungi are major decomposers on earth◦ no decomposers=no carbon cycle on earth◦ produce spores Facultative parasites:grow on living organisms,but can grow by themselves Obligate parasites:only grow on specific living host  Lichens: association of fungi with cyanobacteria,photosynthetic alga, or both◦ susceptible to poor air quality, but can survive in harsh environments◦ body forms:▪ crustose(crustlike):lichens look like colored poweder dusted over substrate▪ foliose(leafy)▪ fructicose(shrubby)◦ reproduce by fragmentation of vegetative body(thallus) or by specialized structures (soredia) Mycorrhizae:association of fungi and roots of plants◦ fungus obtais material and provides minerals and water to plant◦ endomycorrhizae:fungus wraps around root▪ dont penetrate cell walls▪ increase surface area for absorption of water/minerals◦ arbuscular mycorrhizae:enter root and penetrate cell walls of root cells▪ form arbuscular (treelike) structure inside cell wall◦ fungus provides better absorption of H20 and obtains organic compounds from plant▪ may provide plant with growth hormones and protection from disease causing microbes◦ plants that lakc chlorophyll have mycorrhizae Endophytic fungi:fungi that live within plants and don't cause obvious deleterious symptoms  6 major groups of fungi◦ microsporidia◦ chytrids◦ zygospore fungi◦ arbuscular mycorrhizal fungi◦ sac fungi◦ club fungi Asexual reproduction forms◦ production of haploid spores within structures called sporangia◦ production of haploid spores at tips of hyphae called conidia◦ Cell division by unicellular fungi: ▪ fission:equal division of cell into 2▪ budding:asymmetrical division in which smaller daughter cell produced  Individuals of same mating type cannot mate◦ can mate with other mating type of same species Microsporidia◦ unicellular parasitic fungi◦ lack mitochondria have reduced structures(mitosomes)▪ mitosomes contain no DNA◦ hots cell penetrated by polar tube that grows from microsporidian spore ▪ contents injected into cell called sporoplasm chytrids◦ possess flagellated gametes◦ only fungi to have flagella at any lie cycle stage◦ reproduce both asex. And sex.◦ Parasitic and mutualistic Other 4◦ cytoplasms of two individuals of different mating type fuse (plasmogamy) before nuclei fuse (karyogamy)◦ Zygospore=resting stage undergoes meiosis to become sporangiophore◦ Sporangiophore:fruiting structure Arbuscular mycorrhizal fungi◦ Symbiotic, mutualistic relationship with plants◦ hyphae=coenocytic◦ reproduce asex. Last 2◦ two genetically different haplod nuclei co-exist and divide within each cell of mycelium▪ stage is dikaryon▪ ploidy indicated by n+n Sac fungi◦ distinguished by production of sacs called asci Club fungi◦ septate=hyphae◦ Basidium (swollen cell at tip of specialized hypha) is characteristic◦ basidiomata=fruiting structure, basidia=reproductive

View Full Document

UNLV BIOL 197 - Chapter 22

Download Chapter 22
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...

Join to view Chapter 22 and access 3M+ class-specific study document.

We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Chapter 22 2 2 and access 3M+ class-specific study document.


By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?