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Lecture Biology: Chapter 31 - Niel Campbell, Jane Reece

Chapter 31 introduce to fungi. This chapter list the characteristics that distinguish fungi from other multicellular kingdoms, discuss mycorrhizal fungi, describe the processes of plasmogamy and karyogamy, describe the processes of plasmogamy and karyogamy,.and another content. | Chapter 31 Fungi Overview: Mighty Mushrooms Fungi are diverse and widespread. They are essential for the well-being of most terrestrial ecosystems because they break down organic material and recycle vital nutrients. Fungi are heterotrophs and absorb nutrients from outside of their body. Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds. The versatility of these enzymes contributes to fungi’s ecological success. The most common body structures are multicellular filaments and single cells (yeasts). Some species grow as either filaments or yeasts; others grow as both. Fungi exhibit diverse lifestyles: Decomposers / saphrophytes Parasites + - Mutualists + + Fungal Morphology : hyphae The morphology of multicellular fungi enhances their ability to absorb nutrients. Fungi consist of mycelia, networks of branched hyphae adapted for absorption. Most fungi have cell walls made of chitin. Multicellular Fungus: hyphae Reproductive structure Spore-producing structures Hyphae Mycelium 20 µm Figure 31.2 Structure of a multicellular fungus Septate fungi - Some fungi have hyphae divided into cells by septa, with pores allowing cell-to-cell movement of organelles. Coenocytic fungi lack septa. Some unique fungi have specialized hyphae called haustoria that allow them to penetrate the tissues of their host. Two forms of hyphae (b) Coenocytic hypha Septum (a) Septate hypha Pore Nuclei Nuclei Cell wall Cell wall Figure 31.3 Two forms of hyphae Specialized Hyphae in Mycorrhizal Fungi + + Mycorrhizae + + are mutually beneficial symbiotic relationships between fungi and plant roots. Ectomycorrhizal fungi form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex. Arbuscular mycorrhizal fungi extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane. Fungus - have specialized hyphae (b) Haustoria - penetrate cell walls of plants ++ or +- (a) | Chapter 31 Fungi Overview: Mighty Mushrooms Fungi are diverse and widespread. They are essential for the well-being of most terrestrial ecosystems because they break down organic material and recycle vital nutrients. Fungi are heterotrophs and absorb nutrients from outside of their body. Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds. The versatility of these enzymes contributes to fungi’s ecological success. The most common body structures are multicellular filaments and single cells (yeasts). Some species grow as either filaments or yeasts; others grow as both. Fungi exhibit diverse lifestyles: Decomposers / saphrophytes Parasites + - Mutualists + + Fungal Morphology : hyphae The morphology of multicellular fungi enhances their ability to absorb nutrients. Fungi consist of mycelia, networks of branched hyphae adapted for absorption. Most fungi have cell walls made of chitin. Multicellular Fungus: hyphae Reproductive structure .