Fungi Flashcards
Are fungi eukaryotes or prokaryotes?
Eukaryotes - they have a nucleus and membrane bound organelles
Where are fungi found?
In terrestrial environments
Fungi are saprotrophic, what does that mean?
They are primary decomposers of dead and organic matter
How do fungi reproduce?
Sexually and asexually
How can fungi be classified?
By morphology = the structures produced during sexual reproduction
By evolutionary relationships
What fungi is likely to be the first fungi to have evolved?
Chytridiomycota
What are the features of chytridiomycota?
Lively mostly in water and soil
Mostly saprotrophs
Asexual and sexual zoospores have flagella - enabling motility
Major threat to amphibian species
What are the features of zygomycota?
Saprotrophs
Hyphae lack cross walls and are multinucleate
What does asexual production of zygomycota produce?
Sporangiospores
What does the sexual production of zygomycota produce?
Zygospores
What are the features of ascomycota?
Plant pathogens
Saprotrophs
Symbiotic partner in lichens
Morphologically diverse
Name three examples of ascomycota.
Yeasts
Mould
Truffles
What does the asexual reproduction of ascomycota produce?
Conidia
What does the sexual production of ascomycota produce?
Ascospores
What are the features of basidiomycota?
Mainly saprotrophs
Some plant pathogens
Septate hyphae
Name three examples of basidiomycota?
Mushrooms
Puffballs
Birds next fungi
What does the rare asexual production of basidiomycota produce?
Arthrospores
What does the sexual reproduction of basidiomycota produce?
Basidiospores
When are spore forming structures produced?
In both sexual and asexual reproduction
What are hyphae?
Thin thread-like filaments found in fungi
What are mycelium?
Filamentous mass grown from hyphae
What are septa?
Hyphae containing cross walls which produces uninucleate cell like units
What are conenocytic hyphae?
Hyphae that does not contain cross walls which makes it appear multinucleate
What do the cell walls of fungi contain?
Chitin
What other organelles are found in fungi?
Vacuoles ER Ribosomes Mitochondria Golgi apparatus Nucleus
Fungi are heterotrophs, what does this mean?
They do not make their own food
They obtain nutrients from pre-formed sources of organic carbon
In what form do fungi store food?
Glycogen
Where and why are enzymes secreted before intake of nutrients?
From hyphae tips to break down food so that they can intake the nutrients
What happens when there is mechanical damage to cell walls in fungi?
Septal ‘plugs’ block septal spores
How fast does the cytoplasm stream?
12cm per hour
In what direction does cytoplasmic streaming occur?
Unrestricted bi-directional flow
Name three forms of asexual production.
Hyphal fragmentation
Production of spores
Uneven cell division
What happens during hyphal fragmentation?
Asexual spores formed by the septation and fragmentation of hyphae
What happens during the production of spores?
Asexual spores formed by mitosis at the tips of specialised hyphae
What happens during uneven cell division?
- Budding = parent cell forms a bud on the outer surface
- As the bud grows the parent cell’s nucleus divides and one nucleus migrates into the bud
- Cell wall material is laid down between the bud and the parent cell
- The bud breaks away leaving a scar
What pH do fungi grow best in?
pH 5
Why can fungi grow in relatively high salt or sugar concentrations?
Because they are more resistant to osmotic pressure
Can fungi grow on substances with low moisture content?
Yes
Do fungi require a continuous water phase for growth?
No
Do fungi need nitrogen for growth?
Little
Are fungi capable of metabolising complex carbohydrates?
Yes - lignin
Name three threats to fungal plants.
Rice blast disease
Wheat stem rust
Late potato blight
What is symbiosis?
Interactions between two different organisms living in close physical association that typically advantage both
What is mycorrhizae?
Mutualistic relationship between fungus and a plant root
What does the plant gain from fungi in mycorrihizae?
Fungus functions like a root by growing in the soil and absorbing nutrients
What does the fungi gain from plants in mycorrihizae?
Plant provides energy
What is lichen?
Associated between fungi and a photosynthetic organism or green alga
What does the photosynthetic organisms gain from the fungi in lichen?
Fungi provides structure
What does the fungi gain from the photosynthetic organism in lichen?
Photosynthetic organism provides food
What are the two main forms of association?
Ectomycorrhiza
Arbuscular mycorrhiza
What is ectomycorrhiza?
Symbiotic relationship between fungi and roots of various plants
- Fungi forms between roots
What is arbuscular mycorrhiza?
Symbiotic relationship between fungi and roots of various plants
- Fungi penetrates the root
Name three ways in which fungi act as pathogens.
Superficial infections
Subcutaneous fungal infections
Systemic mycoses
What are superficial infections?
Infections of the outer layer of the skin hair and nails
- Athletes foot
- Ringworm
What are subcutaneous fungal infections?
Infections that usually occur in deep layers of the skin or in underlying bone
What are the treatments for subcutaneous fungal infections?
Local surgery
Antibiotic treatment
What are systemic mycoses?
Infections that occur via the inhalation of fungal spores by individuals with weak immune systems
What are opportunistic infections?
An infection caused by pathogens that takes advantage of an opportunity not normally available (weak immune system)
