Chapter 31 Notes Fungi

Concept 31.1 All fungi are eukaryotic; most are multicellular mycete = fungi Fungi differ from plants in nutritional mode, structural organization, growth, and reproduction

Concept 31.1 Fungi are heterotrophs that acquire their nutrients by absorption - fungi digest their food outside their body by secreting powerful hydrolytic enzymes (exoenzymes) into the food. - decomposers, parasites, and mutualistic symbionts

Concept 31.1 Fungi have a large surface area and grow rapidly to assist with absorption The bodies of fungi are constructed of tiny filaments called hyphae - the hyphae are divided into cells by cross-walls, or septa - cells walls are made of chitin

Concept 31.2 Fungi disperse and reproduce by releasing spores that are produced sexually and asexually - heterokaryotic stage: fusion of two hyphae that have genetically different nuclei

More than 100,000 fungi species are known; estimated that 1 More than 100,000 fungi species are known; estimated that 1.5 million may exist Phylum Chytridiomycota: - chytrids are mainly aquatic - saprobes or parasites - most primitive fungi; ancestors of protists

Phylum Zygomycota: - mostly terrestrial; live in soil or on decaying plants and animals - many form mycorrhizae, a mutualistic association with the roots of plants

Phylum Ascomycota: - sac fungi - range from unicellular yeasts to cup fungi - produce spores in saclike asci

Phylum Basidiomycota: - “club fungus” - mushrooms, puffballs, and rusts - important decomposers of wood and other plants

Concept 31.5 Molds, yeasts, lichens, and mycorrhizae have specialized lifestyles Molds - a rapidly growing, asexually reproducing fungus Yeasts - unicellular fungi that inhabit liquid or moist habitats

Concept 31.5 Lichens - symbiotic relationship of millions of photosynthetic microorganisms (alga) held in a mesh of fungal hyphae - the alga provides the fungus with food. The fungus provides a suitable environment for growth

Concept 31.5 Mycorrhizae - mutualistic association of plant roots and fungi - responsible for making nutrients able to be absorbed