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A Kingdom of its Own
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Eukaryotic organisms
Some fungi look like plants (i.e. mushrooms),
but they are not.
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Few types are unicellular (E.g.
Saccharomyces cerevisiae aka yeast)
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Most are multi-cellular
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Adapted for two main
functions
 Absorption of nutrients
 Reproduction
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The bodies of multi-cellular
fungi are made up of a thin
thread of cells called hyphae
(string is called hypha)
A network or branching
hyphae are called a mycelium
Mycelium network of hyphae
Reproductive Structures
Mycelium – branching
network of hyphae
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Most fungi are saprophytes – feed on dead or
decaying matter
 As fungi hyphae grow across a food source, they
release enzymes (proteins) outside the cell to help
break down the source into smaller molecules –
Extracellular digestion
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The larger the surface area the mycelium
occupies, the greater the amount of nutrients
absorbed
Some fungi are parasites of
plants and animals and can
cause diseases
 such as Athlete’s foot
(Epidermophyton floccosum)
and ringworm
 (Microsporum).
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 Parasitic fungi are specialized
to feed on living cells
 There have hyphae called
haustoria that can penetrate
host cells without immediately
killing them
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Most fungi live in symbiosis with plants and
animals – live to benefit both organisms
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Symbiotic relationship: a relationship
between two organisms in which both
partners benefit from the interaction.
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Example: Mycorrhiza relationship –
mycelium of fungi grows around plant roots,
absorbing nutrients from the soil and
releasing it into the roots
 The fungi absorbs nutrients like sugars and amino
acids from the plant in exchange
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Fungi are used in everyday things: all the
citric acid used in soft drinks, candies,
artificial lemon juice, and baked goods is
produced industrially by fungus fermentation
using Aspergillus niger
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Saccharomyces cereviseae is used in
fermentation processes that result in the
production of beers, wines and spirits
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Other fungi provide numerous drugs (such as
penicillin and other antibiotics), foods like
mushrooms, truffles and morels
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Most Fungi have both asexual and sexual
methods of reproduction
The simplest form of asexual reproduction is
by fragmentation
 Pieces of hyphae are broken off and grow into a
new mycelium.
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Most fungi live on land. To disperse
themselves, Sporangia (reproductive
structure) release spores in great numbers
Spores: Lightweight reproductive cells
Spores are easily transported on bodies of
insects, birds or by the wind
 Spores can grow directly into a new organism in a
suitable environment
 Spores can be sexual or asexual
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At one time, fungi were included with plants
Now they have their own kingdom with four
subgroups
Deuteromycota
(Imperfect Fungi)
20,000 species
Basidiomycota
Club Fungi
25,000 species
Zygomycota
Ascomycota
Zygospore Fungi
Sac Fungi
1,500 species
30,000 species
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PG. 458 #1, 2, 4, 5, 6