Unit 6--Microbiology

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Unit 6--Microbiology

• Chapter 21
• Fungi

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Fungal Characteristics

• Filamentous bodies
• Hyphae thin filaments
• Mycelium entire mass of hyphae
• Chitinous cell walls (instead of cellulose)

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Fungal invasion in leaf
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Fungal characteristics

• How they obtain food
• 1) Secrete digestive enzymes into environment
• 2) Digestion takes place outside their body
• 3) They absorb what they need, leaving the rest
• Why is this an advantage ?
• (to the rest of the world)

(Compost)
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Fungal characteristics

• Reproduction
• 1) Asexually (usually used when times are good
  with plenty of food available)
• Haploid spores produced in large numbers
• 2) Sexually (usually used when times are harsh)
• Haploid gametes fuse to form a zygote that can
  survive hard times

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Phylumexamplestypes of reproduction

• Zygomycota (Zygote-producing
  fungus)
• Rhizopus (black bread mold)
• Asexual with sporangia
• Sexual with zygospores

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Phylumexamplestypes of reproduction

• Zygomycota (Zygote-producing
  fungus)
• Rhizopus (black bread mold)
• Asexual with sporangia
• Sexual with zygospores

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Sporangia can produce 50,000 spores
Formed when 2 gametes unite to form a zygote
that in enveloped by a zygospore which survives
harsh times
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Rhizopus sporangia _at_ 2,990 x
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Phylumexamplestypes of reproduction

• Ascomycota (cup fungus)
• Ex yeast, truffles, many other molds
• Asexual with conidia
• Sexual with ascus (sac-like spore case) inside a
  cup

(900 per pound!)
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Aspergillus conidia
Asci (with 8 spores) making up the cup
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Phylumexamplestypes of reproduction

• Basidiomycota club fungus
• Ex mushrooms, toadstools, puffballs, bracket
  fungus
• Asexual is rare
• Sexual is club-shaped spore case called basidium

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10X
4X
40X
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Phylumexamplestypes of reproduction

• Deuteromycotaimperfect fungus
• Ex ringworm, athletes foot, penicillium mold
• Asexual only
• No known sexual stage

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Other relatives

• Lichens
• Symbiotic fungus algae
• Fungus provides home, algae provides
  food

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• Mycorrhizae
• Symbiotic fungus plant root cells
• Root cells provide home
• fungus provides mineral transport