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Body Structure
• The morphology of multicellular fungi
– Enhances ability to absorb nutrients
– Chitin
Hyphae. The mushroom and its subterranean mycelium are a continuous network of hyphae.
Reproductive structure.The mushroom producestiny cells called spores.
Spore-producing structures
20 µm
Mycelium
Figure 31.2
Hyphae
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Hyphal Structure
• Most are multicellular
– Cells divided by septa
• Some have no cross wall- Coenocytic Figure 31.3
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Figure 31.4a, b
haustoria
Hyphal Structure
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Nematode Hyphae25 µµµµm
(a) Hyphae adapted for trapping and killing prey
Figure 31.4a, b
Hyphal Structure
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Mycorrhizae
• Are mutually beneficial relationships between
fungi and plant roots
– Mycorrhizae “fungus roots”
• Delivers minerals and receives organic nutrients
– Ectomycorrhizal fungi: Grow in extracellular spaces of roots
– Endomycorrhizal fungi: Hyphae go through cell wall to plasmamembrane
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• Mycorrhizae
– Increase plant productivity
RESULTS
Figure 31.21
RESULTS
Fungus-Plant Symbiosis
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Malted barley
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Saccharomyces cerevisiae
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• Brewer's yeast tolerate up to about 5% alcohol. Beyond this alcohol level the yeast cannot continue fermentation. Wine yeast on the other hand tolerates up to about 12% alcohol. The level of alcohol tolerance by yeast varies from 5% to about 21% depending on yeast strain.
• Part 1 Aerobic (Oxygen is present) This is the initial rapid process where the yeast is doubling its colony size every 4 hours. (Usually 24-48 hours)
• Part 2 Anaerobic. (No oxygen present) Slower activity and the yeast focuses on converting sugar to alcohol rather that increasing the number of yeast cells. (This process can take from days to weeks depending on the yeast and the recipe)
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• The overall process of fermentation is to convert glucose sugar (C6H12O6) to alcohol (CH3CH2OH) and carbon dioxide gas (CO2). The reactions within the yeast to make this happen are very complex but the overall process is as follows:
• C6H12O6 ====> 2(CH3CH2OH) + 2(CO2)Sugar ====> Alcohol + Carbon dioxide gas
(Glucose) (Ethyl alcohol)
•Note: The sugars used can be a range of fermentable sugars.
These sugars are converted by enzymes to glucose which is then convered to alcohol and CO2
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Diploid phase follows karyogamy
• Short-lived (2n) spore-producing structures and
(1n) spores
SporangiaBasidiocarp
Ascocarp
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• Concept 31.3: Fungi descended from an
aquatic, single-celled, flagellated protist
• Fungi and Animalia as sister kingdoms
• Fungi early colonizers of land, probably as symbionts with plants.
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• Concept 31.4: Fungi radiated into a diverse
set of lineages
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Hyphae
Chytrids
• Found in freshwater and terrestrial habitats
• They can be saprobic or parasitic
• Zoospores: unique with flagellated spores
Figure 31.10
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• Fast growing bread and fruit molds
• Can also be parasitic or symbiotic relationship
Zygomycetes
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Rhizopusgrowingon bread
Matingtype (+) Mating
type (–)
PLASMOGAMY
Key
Haploid (n)
Heterokaryotic (n + n)
Diploid (2n)
100 µm
SEXUALREPRODUCTION
KARYOGAMY
Zygosporangium(heterokaryotic)
Diploidnuclei
MEIOSIS
Sporangium
Mycelium
Dispersal andgermination
Dispersal andgermination
ASEXUALREPRODUCTION
Sporangia
50 µm
Zygospore
Zygomycetes
Figure 31.13
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• Pilobolus “aim” their sporangia toward the light
Zygomycetes
Figure 31.14
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• Pilobolus “aim” their sporangia toward the light
Zygomycetes
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Glomeromycetes
• arbuscular mycorrhizae
• See Figure 31.15
http://www.agro-genesis.com/pics/cropscience_rhizogold1.jpg
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Ascomycetes
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Glomeromycetes
• Spores produced in a saclike asci “sac fungi”
• Asci are within the ascocarp
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Basidiomycetes
• Include mushrooms and shelf fungi
• Clublike structure
called a basidium
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Mushrooms are examples of basidiocarps
Figure 31.20
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• Concept 31.5: Fungi have a powerful impact on
ecosystems and human welfare
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Decomposers
• Essential recycling between the living and
nonliving world
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Fungus-Animal Symbiosis
• Helping break down plant material
Figure 31.22
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Lichens
• Symbiotic association of photosynthetic
microorganisms held in fungal hyphae
(a) A fruticose (shrub-like) lichen
(b) A foliose (leaf-like) lichen (c) Crustose (crust-like) lichensFigure 31.23a–c
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Lichens
• The fungal component
– Is most often an Ascomycete
• Algae or cyanobacteria
– Occupy an inner layer below the lichen surface
Ascocarp of fungus
Fungal
hyphaeAlgal
layer
Soredia
Algal cell
Fungal hyphae
10 µ
m
Figure 31.24
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Pathogens
• About 30% of known fungal species
– Are parasites, mostly on or in plants
(a) Corn smut on corn (b) Tar spot fungus on maple leaves (c) Ergots on ryeFigure 31.25a–c
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Practical Uses of Fungi
• Make cheeses, alcoholic beverages, and bread
• Genetic research on fungi is leading to
applications in biotechnology
• Antibiotics produced by fungi treat bacterial
infections
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Charophytes
ANCESTRALALGA
Red algae
Chlorophytes
Charophytes
Embryophytes
Virid
ipla
nta
e
Stre
pto
ph
yta
Pla
nta
e
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• 3 billion years terrestrial surface was lifeless
• Now roughly 290,000
living plant species
Overview: The Greening of Earth