Fungi Flashcards
What are fungi
Fungi are Unikonta whcih means that they are really closely related to animals.
What are some characteristics of Fungi?
Fungi are:
- Eukaryotes
- most are multicellular (but few are unicellular)
- Have a cell wall made of chitin
- diverse and wide spread
- about 100000 species described (estimated 1.5million)
- diverse reproductive cycles
- play essential ecological roles:
- break down organic material
- recycle vital nutrients
Are Fungi Heterotrophs or Autotrophs?
All fungi are heterotrophs, however they do not feed like animals they feed by absorbtion, they cannot make their own food.
How do Fungi eat?
Digestive enzymes (hydrolytic enzymes) secreted outside the body break down the bonds in large food particles in environment and smaller molecules are then absorbed into cells. They have a versitile range of enzymes which explains their ecological success.
What are the different types of fungi?
- Decomposers (“saprobes”) - absorb nutrients from dead organic material
- Parasites - absorb nutrients from the cells of living hosts
- Predators - trap animals and digest them
- Mutualists - absorb nutrients from a host, but reciprocate with actions that benefit the host
How do predatory fungi get their food?
- Some secrete sticy substances that trap prey
- others trap prey with hoop-like traps
What it hyphae?
Thread-like filaments that make up a multicellular fungus and release enzymes to absorb nutrients from food sources
What is Mycelium?
The vegetative part of a fungus, consisting of a network of fine white filaments (hyphae).
Draw structure of Septate hypha
in back of excersize book
Draw structure of Coenocytin Hypha
in back of exercise book
How do Fungi reproduce?
By producing spores:
- vast number of spores (puffballs can release trillions of spores)
- when released, carried away, land, and if environment is moist and there is food, germinate, producing a new mycelium
What are the two ways fungi can reproduce?
- Asexual: spores produced by mitosis
- Sexual: more complicated … includes:
- sexual signalling molecules (pheromones) and
- Fusion of hyphae ->fusion of cytoplasim (“plasmogamy”) -> fusion of nuclei (karyogamy) -> diploid cell … meiosis then restores normal haploid conditioning
Draw the generalised life cycle of fungi
in workbook
How many different phyla of fungi do we have and what are they based on?
There are currently five and they are based on reproductive structures
What are the five Phyla of fungi?
1) Chrytridiomycota
2) Zygomycota
3) Glomeromycota
4) Ascomycota
5) Basidiomycota
What is Phylum Chrytridiomycota?
A phylum of fungi where the chytrids have flagellated spores called zoospores, but are true fungi (chitin cell walls, absorbtive mode of nutrition, hyphae)
What is Phylum Zygomycota?
A phylum of fungi that has alot of diversity and includes fast growing moulds, parasites and commensal symbionts
- named for their sexually produced “zygosporangium”
- resistant to freezing and drying
What is phylum Glomeromycota?
a phylum of fungi that includes glomeromycetes which are an ecologically important group: nearly all form arbuscular mycorrhizae with plants
- mycorrhiza: fungal hyphae colonise plant root
- Arbuscular mycorrhiza:hyphae reach inside the plant cell (through cell wall)
- important beneficial partnership for plants (increases “root” surface area for nutrient acquisition by 200x)
- 80% of plants have relationship with glomeromycetes
What is Phylum Ascomycota?
A phylum of fungi where 65 000 species described and they have a varied clade:
- variety of habittas (marine, freshwter, terrestrial)
- unicellular yeasts to complex multi cellular fungi
defining feature is production of spores in sac-like “asci” (micro-macroscopic)
What is Phylum Basidiomycota
Phylum of fungi where the name in derived from “basidium”, club-shaped spore producig structure in diploid stage
- AKA “club fungi
Very important for decomposing, like wood and other plant material (particularly lignin, an abundant component of wood
What are some of the key ecological roles of fungi?
- play key roles in nutrient cycling, ecological interactions and human welfare
- they interact with many species from diverse kingdoms of life
- decomposers
- mutualists
- pathogens
Why are decomposer fungi important?
Their enzymes can break down almost any corbon-containing substrate (like cellulose and lignin)
they are so effective at breaking down stable carbons that they are being used to break down sewage.
Biotech applications
recycles elements like C, N and other elements which would not otherwise remain tied up in organic matter
without decomposers, life as we know it would cease to exist
What happens in mutualistic relationships with plants and fungi?
Myccorhizae: symbiosis between plant and fungi that dramatically increases water and nutrient supply for plant in exchange for sugars from plant for fungi
- ectomycorrhizae - outside root cell
- endomycorrhizae - inside root cells
fossil record suggest this was important for colonisation of land by plants
What are mutualistic relationships with animals and fungi?
some fungi share digestive services with animals, helping break down plant material in the guts of cows and other mammals
What are mutualistic relationships with fungi and protists?
Lichen: highly integrated symbiotic association of algal cells (usually filamentous green algae or cyanobacteria) with fungal hyphae (usually ascomcetes)
- protist provides C and N compounds
- ungus provides moist environment and minerals
What percentage of fugal species are parasites or pathogens
30%, mostly on or in plants, each year 10-50% of the worlds fruit harvest is lost due to fungi
What are human and fungal pathogens?
infected by fungal parasite = “mycosis”
- often by inhalation of spores
What are some beneficial human uses of fungi?
- medicine: many pharmaceutical ingredients are isolated from fungi
research: Saccharomyces cerevisiae is widely used model to study genetics of eukaryotes
bioremediation: isolated fungal enzymes break down organic contaminants in wastewater
