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FUNGI
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Microbiologists use the term "fungi" to include the eukaryotic, spore
bearing organisms with absorptive nutrition, no chlorophyll and that
reproduce sexually and asexually.
Scientist who study fungus are called as mycologists and
the scientific discipline dealing with fungi is called as
mycology. The study of the fungal toxins and their effects is
called as mycotoxicology, and the diseases caused by
fungi in animals is called as mycoses.
The five kingdom classification places the fungi in the kingdom FUNGI.
According to the universal phylogenetic tree, fungi are members of
domain eucarya. |
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DISTRIBUTION of fungi
They are primarily terrestrial organisms, although a few are fresh
water or marine. Many are pathogenic and and infect plants and
animals. They also form beneficial relationship with other organisms.
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IMPORTANCE of fungi
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Act as decomposers.
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cause disease in animals and plants.
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essential for many industrial processes involving fermentation.
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commercial production of many organic acids and certain drugs.
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in manufacture of many antibiotics
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acts as important research tools in the study of fundamental
biological processes.
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STRUCTURE
The body or the vegetative structure of fungus is called a thallus. it
varies in complexity and size ranging from the single -cell
microscopic yeasts to multicellular molds, macroscopic puffballs, and
mushrooms. the fungal cell is encased in a cell wall of chitin.
chitin is a strong but flexible nitrogen containing polysaccharide
consisting of N-acetyl glucosamine residues.
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A yeast is a unicellular fungus that has a single nucleus and
reproduces either asexually by budding or by transverse division
or through spore formation. each bud that separates can grow into
a new yeast. and some group together to form colonies. generally
yeast cells are larger than bacterial cells, vary considerably in
size and are commonly spherical to egg shaped. they have no
flagella but do posses most of the other eukaryotic organelles.
A mold consists of long, branches, Thread like filaments of cells
called hyphae, that form the mycelium, a tangled mass or tissue
like aggregation. in some fungi protoplasm streams through hyphae,
uninterrupted by cross walls. these hyphae are called coenocytic. |
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The hyphae of other fungi have cross walls called septa with
either a single pore or multiple pores that permit cytoplasmic
streaming. These hyphae are called as septate.
NUTRITION & METABOLISM
They grow best in dark moist habitats, but they are found wherever
organic material is found. Most fungi are saprophytes. They release
hydrolytic exoenzymes that digest external substrates, they then
absorb the soluble products. They are chemo organoheterotrophs and
derive carbon, oxygen and electrons from organic source.
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