Fungi Flashcards
classification
- Eukaryotic
- most closest related Kingdom is to animals
Key characteristics
- Although often mistaken for plants, fungi are unique from both plants and animals
- fungi (singular:fungus) are some of the most common but least visible organisms on Earth. They often grow out of sight- underground or within other organisms that might be dead or alive.
Main characteristics:
- Mostly multicellular
- cells have chitin(a carbohydrate) therefore, not photosynthetic
- All are heterotrophic(no photosynthesis)
- Most are terrestrial and sessile(stationary)
- Reproduce sexually(using spores) and asexually
Importance of Fungi
positive:
- major decomposers on earth (along with bacteria)
- responsible for cycling nutrients through the biosphere
- engage in symbiotic relationships with plants- plants rely on fungi to help them obtain nutrients
Negative:
- responsible for some diseases in animals and many serious diseases in plants (economic implications related to agriculture, eco-tourism, and forestry)
- eg. Dutch Elm disease
other uses:
- Food-mushroom, truffles, yeast in bread, soya sauce, blue cheese, beer, and wine
- Medicine-Penicillin(antibiotic), cyclosporine (anti-rejection drug for organ transplant)
General structure of Fungi
-Fungi are composed of hyphae which are elongated cells that form a branching filamentous structure
-Many hyphae are divided into individual cells by cell walls called septa
Multiple hyphae forming a branching network filaments is called a mycelium
Phylogeny
-5 major phyla – the most recognizable phyla are Basidiomycota (phylum containing most mushrooms) and Zygomycota (phylum containing most fruit and bread mould)
Phylum: Ascomycota
Key Features:
- Sexual spores formed in sac-like “ascus”
- Important to humans for fermentation, and food
- Very diverse
Examples of ascomycetes:
- Yeasts
- Truffles
- Morels
- Dutch Elm Disease
- Chestnut blight
Phylum: Basidiomycota
Key Features:
- Produce “mushroom-cap” fruiting bodies
- Mostly Decomposers
Examples of basidiomycetes:
- Puffballs
- Brack fungi
- Toadstool
Phylum: Zygomycota
Key Features:
- Mostly soil fungi
- Multinucleate hyphae
- non-septate
Examples of zygomycetes:
- Bread mould
- Fruit mould
Phylum: Chytridiomycota
Key Features:
- Mostly decomposers
- Some unicellular, some multicellular
- Some have “swimming spores
Phylum: Glomeromycota
Key Features:
-All form symbiotic relationships with plant roots
Extracellular Digestion
- Fungi do not have a digestive system
- They are saprophytic because they absorb their nutrients from nearby decaying matter.
- Digestive enzymes are secreted into the surrounding environment
- Enzymes breakdown food into smaller molecules that can be absorbed into the hyphae
Symbiotic Relationships
Lichen
Partnership between fungus and cyanobacteria (green algae)
-Fungus provides structure, can digest / absorb nutrients and water and can protect from harsh conditions
-Cyanobacteria or algae produce sugar (food)
Mycorrhizae
Partnership between fungus and plant roots
-Fungus provides increased capacity for absorption of nutrients and water
-Plant produces sugar (food)
Application
Sir Alexander Fleming:
- Accidentally discovered penicillin, the first antibiotic, in 1928
- Before this time there was no effective treatment for bacterial infections
- He had been growing petri dishes of bacteria and noticed that one petri dish did not show bacterial growth
- Mould had started growing on the dish and killed the bacteria
- The mould was later identified as Penicillium notatum
