Biology Chapter 31 Objectives

Biology Chapter 31 Objectives - Chapter 31 Fungi...

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Chapter 31 Fungi Introduction to the Fungi 1. There are many characteristics that distinguish fungi from members of other multicellular kingdoms are. Fungi do not ingest their food; they instead ingest their food while it is still in the environment by secreting powerful hydrolytic enzymes called exoenzymes, into their surroundings. Fungi also have a morphology that enhances their ability to absorb nutrients from their surroundings. Their bodies typically form a network of tiny filaments called hyphae. Hyphae are composed of tubular cell walls surrounding the plasma membrane and cytoplasm of cells. Fungal cell walls also contain chitin, a strong but flexible nitrogen-containing polysaccharide that is also found in external skeletons of insects and other arthropods. Fungal hyphae form an interwoven mass called mycelium that surrounds and infiltrates the material on which the fungus feeds. Its structure maximizes the ratio of its surface area to its volume, making feeding more efficient. The Hyphae are divided into cells by crosswalls or septa, which generally have pores large enough to let ribosomes, mitochondria and nuclei flow from cell to cell. Some fungi lack septa, which are coenocytiv fungi. These consist of a continuous cytoplasmic mass containing hundreds or thousands of nuclei. Some fungi have specialized hyphae that let them feed on animals while others have specialized hyphae called haustoria that allow them to penetrate the tissue of their hosts. These mutual beneficial relationships are called mycorrhizae. There are two different kinds of mycorrhizae: ectomycorrhizae fungi that form sheaths of hyphae over the surface of a root and also grow into the extracellular spaces of the cortex and there are endomycorrhizal fungi which
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This note was uploaded on 08/29/2009 for the course BIOL 101 taught by Professor Sakji during the Fall '08 term at Linn Tech.

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Biology Chapter 31 Objectives - Chapter 31 Fungi...

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