Chapter 30 & 31 Flashcards
prokaryotes
No nucleus, unicellular, few organelles or structure components
eukaryotes
Nucleus, numerous organelles, cytoskeleton
Protists
Eukaryote, not a green plant, an animal or a fungus
fungi
filamentous body (mycelium) obtain nutrients by absorption
Why study Fungi
Nutrient recycling
Carbon Cycle
Economic uses
Nutrient recycling
Most are decomposers
This means that when they are in close association with plants the plants benefit from the increase in nutrients
Mycorrhizal- fungal root
Mycelia
formed by Actinobacteria
Mycelium
formed by a fungus
Carbon Cycle
- Saprophytes: digest dead material
- Land plants Cell walls contain lignin and cellulose
- Fungi break down the wood into sugars and other organic compounds
- Fungi do this faster than other decomposers
Economic impact
- Food: mushrooms,
- Decomposition of food: fungal parasites or mold
- Chestnut trees
- Yeast: bread, soy sauce, cheese, beer
- Fungal enzymes: are used in food production
How do we study them?
Morphologically
Phylogenies: DNA sequencing
Isotope analysis
Morphology
- Two growth forms: yeasts and mycelia
- Some fungi can switch between the two forms
- Yeasts
- Mycelium
- Reproductive structures
Yeasts
Single celled fungi
Form psuedo-hyphae (molds)
Fermentation
Mostly asexual
Mycelium
- Indefinite growth
- Largest found: 6.5 km^2 or 1310 acres
- Mycelium are constantly changing according to food sources
- This means that the bod shape of the fungus changes daily
- Hyphae are very thin, but very long making fungi have the largest Vol to surface area in “multicellular” organisms
- Mycelium are made up of Hyphae
Hyphae
Haploid
heterokaryotic: can contain several nuclei from different parents
Most are dikaryotic
Typically Hyphae are broken up by septa
Septa: wall like structures that separate hyphae , but allow for the transfer of nutrients and genes
If there are no septa than fungi are called:
Coenocytic or common celled
Are fungi multicellular?
Dehydration is common due to thin long hyphae
Reproductive structures
The only reason to expose the hyphae to the risk of dehydration sould be….?
The thick fleshy structures are made of hyphae
Four types of reproductive structures
Reproduction
Four types of reproductive structures
Swimming gametes or spores: produced by Chytrids, asexual, flagella,
Zygosporangia: produced by zygomycetes, two hyphae that ran into each other and form,two hyphae of similar gametes will not mate
Basidia: produced by basidiomycetes, spores inside mushroom, puffball, brackets
Asci: produces by Ascomycetes, spores inside cups, morels, or other outer structures
Fertilization
Typically begins with two hyphae
Two hyphae of similar genetic types will not mate
Instead of male and female you can have thousands of mating types
When two cytoplasm mix: plasogamy occurs
If the nuclei fuse: karyogamy
If nuclei do not fuse the cell is heterokaryotic
The hyphea can then split and grow either with one or two nuclei
Reproductive bodies
Puffballs
Mushrooms
Brackets
Cups
Morels
Other shapes
Fungi and animals
Both use chitin as a structural material
Flagella in animals and on Chytrids are similar
Synthesize food via glycogen
This is why funguses are harder to treat in humans than bacterial infections
Molecular Phylogenies
This is still up for debate
Microsporidians are fungi how they are related is unknown
Chytrids and Zygomycetes are paraphyletic
Glomeromycota, Basidiomycota and Ascomycota: monophyletic
Studies using isotopes
Symbiotic relationships between plants and fungi are common
Use isotopes to look at nutrient movement and categorize the relationships
Mutualistic
Parasitic
Commensal
These studies have shown that many fungi give plants P or N and plants give the fungi sugars and carbon compounds
Diversity
Mutualism types
Decomposition
Lifecycles
Mutualistic relationships: 2 types
Ectomycorrhizal Fungi (EMF):
found in basidiomychota
Sometimes in ascomycetes
Hyphae form a dense covering around root tips
Temperate regions
Use peptidase to break down amino acids
The hyphae secrete proteins suggesting a signaling between the plant and fungi
Arbuscular Mycorrhizal Fungi (AMF):
Glomeromycota
AKA endomycorrhizal
Grow into the root tissue
80% land plant species
Tropical forests and grasslands
Phosphorus is most important uptake
Glomalin: causes organic materials to bind to soil particles
Endophytes
live within the above ground parts of plants
Being newly studied
Mostly seem comensalistic
Mutualism with other species
Lichens: ascomycete and cyanobacteria or algae
Go over more later
Farmer ants: harvest and fertilize the fungus for food
Decomposition
Mycelium
Large surface area
Quick growth toward food (sahrophytic)
Extracellular digestion
Most organic molecules are huge
Hyphea secrete enzyme that break down these materials
Lignin degradation
Very strong source of protection for plants
Lignin peroxidase remove the protective layer from the cellulose
Cellulose degradation
Multiple enzymes are used to degrade cellulose step by step into glucose
Lifecycles
Four types:
Chytridiomycete
Zygomycete
Basidiomycota
Ascomycota
Chytridiomycete
Swimming gametes
Diploid zygote
Sporophyte -> sporangium: bosy where spores are stored
Zygomycete
protected from cold or draught
Basidiomycota
produce and eject spores
Ascomycota
Form specialized structures to fuse together
Major Lineages
Microsporidia
Chytrids
Zygomycetes
Glomeromycota
Basidiomycota
Ascomycota - > lichen formers
Ascomycota -> non lichen formers
Microsporidia
Single celled
Parasitic
1200 species
Absorption
Life cycles vary
Honey bee and silk worm psets
Attack AIDS patients
Used as a pesticide for grasshoppers
CHytrids
Mostly aquatic
Spores can germinate after 31 years
Motile cells
Have many cellulose enzymes
Can hurt algae or live in stomachs of animals and help
Parasitise mosquito larvae
Are a main cause for amphibian declines
Zygomycetes
Zygosporangium
Soil dwellers
Many are saprophytes
Common bread mold
Fruit molds
Steroids (medical use)
Glomermycota
Arbuscular mycorrhizal fungi
Phosphorus
Life cycle not well studied
Very important because is common in grasslands and tropics
Basidiomycota
Club like or pedastal like
31000 species
Can completely digest wood with lignin peridoxase
Forms “rusts” on plants
“smuts” on grass
Has heterokaryotic mycelia
Ascomycota- lichen formers
Live in symbiosis with an algae or cyanobacterium
15000 lichens
Partially parasitic
Lichens are protective of the bacterium most of the time
Perfume production
Ascomycota – non lichen formers
Found everywhere
EMF associations
Endophytic fungi
Some are predatory on amoebe or unicellular protists
Set snares or use sticky substances
Ascocarp: above ground structure
Cleans contaminated sites
Truffles and morels
Dutch elm disease