Fungi Flashcards
give some examples of fungal derived products
- citric acid was originally sourced from fungi
- enzymes in bio detergents
- fermented products
- yeast in bread
- ANTI MALARIAL DRUG
what are fungi? where are they mainly found?
- eukaryotes
- mainly in terrestrial environments
what type of nutrition do fungi rely on?
SAPROTROPHIC NUTRITION, decomposee dead matter
what are the 5 diff types of fungi? describe the types of spores that each of them make
- CHYTRIDIOMYCOTA-motile zoospores
- ZYGOMYCOTA- zygospores
- ASCOMYCOTA- ascospores
- BASIDIOMYCOTA- basidiospores
- DEUTEROMYCOTA- nosexual cycle found- other
what is the asexual repro cycle of fungi?
- mycelium (n)— spore producing structures (n)— spores (n)— [GERMINATION]-mycelium
what is the sexual reproduction cycle in fungi?
- mycelium (n)— [PLASMOGAMY-cytoplasm fusion]— Dikaryotic stage (n+n)—[KARYOGAMY -nuclei fuse, genetic variation]— Diploid stage (2n)—[MEIOSIS]—spore producing structures (n)— spores (n)—[GERMINATION]—mycelium
where are chytridiomycota found?
mostly in water and soil
how do chytridiomycota gain nutrients?
mostly saprotrophs or plant parasites
how do chytridiomycota produce motile zoospores?
have flagella
how old are Chytridiomycota?
v old, maybe the first fungi to evolve
where are Zygomycota found?
terrestrial habitats
how do Zygomycota gain nutrition?
saprotrophs and a few pathogens
what are special features of Zygomycete hyphae?
- lack cross walls
- are multi nucleate
what are special features of Ascomycota?
- important pathogens eg rice blast disease
- are ‘sac fungi’
- morphologically diverse, septate hyphae
how do Ascomycota gain nutrition?
saprotrophs and SYMBIOTIC partner in lichens
give some examsples of Ascomycota sac fungi
- yeasts
- moulds
- morels (edible mushrooms)
how do Basidiomycota gain nutrition?
- mainly saprotrophs
- some MAJOR PLANT PATHOGENS
- some form mycorrhizal associations (symbiotic association between fungus and roots of host plant)
give some examples of Basidiomycota
- mushrooms (long lived fruiting body)
- puffballs
describe the structure of filamentous fungi
what are the two diff types?
- has HYPHAE, thin thread like filaments
- hyphae can grow to form a filamentous mass- MYCELIUM
types 1) septate
2) coenocytic
what are septate hyphae?
hyphae with CROSS WALLS (septa), which didvide them into distinct uni-nucleate cell like units
what are coenocytic hyphae?
hyphae with NO CROSS walls and O MULTI NUCLEI
what are the functions of hyphae?
vegetative- absorbs nutrients
aerial-bears reproductive structures
what is the hyphal wall made of?
chitin
do hyphae have organelles?
yes
what are mycelia before they are mycelia?
hyphae and before that a germinating spore
how do fungi gain nutrition? how do they store food?
HETEROTROPHS- do not make own carbon sources/food O obtain from pre formed sources of ORGANIC CARBON
SAPROTROPHS- principle decomposers
- store food as GLYCOGEN
what can filamentous hyphae do to transport things? what does it allow
cytoplasmic streaming
- bi-directional flow of cytoplasm through filaments
- allows continuity and communication in fungal body
- septal plugs block septal pores if there is mechanical damage to cell wall
give an example of non filamentous fungi
yeast-BUT they can exhibit yeast form (single round/oval cells) OR filamentous form
ie temp dependent DIMORPHISM
what are the 3 main ways of asexual repro?
1 Hyphal fragmentation
2 Production of spores
3 Budding- uneven cell division
describe hyphal fragmentation as a method of asexual repro
spores formed from septation and fragmenation of hypha
describe spore production as a method of asexual repro
asexual spores are formed by mitosis at the tips of specialised hyphae
describe budding/uneven cell division as a method of asexual repro
1 parent cell grows a bud on its outer surface
2 parent nuclei divides and one nucleus migrates into bud
3 cell wall material laid down between bud and parent
4 bud breaks off, leaving scar
what kind of env are fungi adapted to live in? how are fungi adapted for their environment?
- adapted to live in environments that would be hostile to bacteria than bac
1 grow better in pH 5, too acidic for most bac
2 more resistant to OSMOTIC PRESSURE O can grow in high sugar/salt con
3 can grow LOW MOISTURE content (lower than bac can cope w/)
4 do NOT NEED CONT WATER PHASES for growth and dispersal
5 need LESS N than bac for same growth
6 can METABOLISE COMPLEX CARBS (ie lignin), most bac cannot
describe rice blast disease
caused by fungus Magnaporthe oryae (a type of Ascomycota), causes 10-35% loss of harvest in around 85 countries
describe wheat stem rust
caused by Puccinia graminis ( a Basidiomycot). Can cause 100% crop loss
what is Mycorrhizae
- mutualistic relationship between fungus and plant root
- fungus grows into soil and absorbs nutrients (like a root)
- plant provides sugars for energy
- contribute N, P, K, Zn, Cu
what are the two types of association?
Ectomycorrhiza and Arbuscular mycorrhiza
describe ectomycorrhiza as a type of association
ie what env, what type of fungi and where
- common in TEMPERATE FOREST ECOSYSTEMS
- Ascomycota and Basidiomycota
- BETWEEN root cells
describe Arbuscular mycorrhiza as a type of association
ie what env, what type of fungi and where
- in GRASSLANDS and TROPICAL ECOSYSTEMS
- Zygomycota
- INVADES root cells
describe the symbiotic relationship between fungi and lichens
- fungi provide the structure
- photosynthetic org provides food
describe and give an example of a superficial infection caused by fungi
- infections of the outer layer of the skin, hair and nails
- eg ringworm (Microsporum)
describe and give an example of a subcutaneous infection caused by fungi. how are they treated?
- in deeper layers of skin and can reach bone
- eg Chromoblastomytosis and Mycetoma
- treat using local surgery and/or antibiotics
describe and give an example of a systemic mycoses infection caused by fungi
- infection is often caused by INHALATION OF FUNGAL SPORES by individuals w/ WEAKENED IMMUNE (eg AIDS, cancer, transplant) O OPPORTUNISTIC inf
- eg Thrush- Candida spp.
- Histoplasmosis (caused by breathing in spore of fungus in bird/bat droppings)
why are fungi important to humans?
- primary decomposers
- produce things like enzymes, drugs, antibiotics etc
- enable food production
CONS - cause plant/animal disease
what features of fungi distinguish them from other forms of life?
- eukaryotes
- have nuclei
- CHITIN cell walls
- ergosterol in membs
main ways of division in fungi asexually?
fragmentation, spore formation and budding
main ways of division in fungi sexually?
spores, but specifics depend on the Phyla of fungi
why is it difficult to treat fungal infections?
- closely relate to humans etc
- O drugs that are toxic to fungi are usually toxic to humans
