Lecture 7 -- Plants Flashcards
Fungi characteristics
spends life as haploid (n), more closely related to us than animals.
heterotrophs, eukaryotic, main body is haploid, multicellular or unicellular
what does heterotroph mean
makes own food
examples of fungi (common names)
bread, athletes food, ringwood, mushrooms, beer
yeast characteristics
ascomycota, unicellular, without flagella
what is fungal cell wall made of
chitin
how does fungi digest
external digestion
what is the basic unit of fungi
hyphae - branching filaments
mycelia
network / mass of hyphae
what are the two kinds of hyphae
septate and coenocytic
septate
has septum, and pores that allow materials through
coenocytic
has no septum, no dividing, body made of continuous cytoplasm
specialized hyphae
predatory fungi, haustoria
haustoria
pathogenic, fungal hyphae that penetrate plant cell wall and expands in that cells
growth in fungi
fungi will digest material outside of its body and then grow.
life cycle of fungus, asexual and sexual – broad overview
Asexual: spores – germination – mycelium – spore-producing structures – spores
sexual: mycelium – plasmogamy – heterokaryotic – karyogamy–zygote – meiosis – spores – germination – mycellium
plasmogamy
fusion of cytoplasm
karyogamy
fusion of nuclei (fertilization)
spores in fungi
haploid – contains nucleus, dehydrated cytoplasm and protective coat
– can sometimes remain dormant
spores asexual vs sexual (production)
produced by mitosis = asexual
produced by meiosis = sexual
asexual reproduction ; spores
spores in sporangia, budding, conidia (spores) in conidiophores
what are fungi closely related to
animals
world of fungi – sex
no sex’s just mating types - and + – gametes are same size
animals and fungi are alien = opisthokonts
what are the 5 phylum of fungi
basidomycota, chytridiomycota, zygomycota, ascomycota, glomeromycota
chytridiomycota (chytrids)
1000 species, single cell or colonies with hyphae, flagellated spore (zoospore) – haploid, asexually produced
aquatic, soil
decomposers, parasites, commensals
chytrid / animals example
chytrids implicated in decline of amphibians – chytrid infests / infects skin
zygomycota
1000 species, black bread mold, coenocytic (non septate), decomposers, parasites, entomophthora (insect killer) – spore infects insects brain, fungus grows, mind control
zygomycota life cycle
asexual: sporangia – spores – mycelium – sporangia
sexual: spores – + and - — plasmogamy – karyogamy – diploid nuclei – sporangium – meiosis – spores
glomeromycota
fungi associated with plants, non-septate hyphae, asexual only, obligate symbionts
what does obligate symbionts mean
obliged to live on plant roots – fungi help plants bring in water and minerals, (mycorrhizae) , land plants supply fungi with sugars ..
basidiomycota
the fungus you think of when thinking of mushrooms, 30,000 species, live OUTSIDE of plant cells (ecto), decomposers, ectomycorrhizal, long-lived dikaryotic mycelium, multicellular and some yeasts, septate hyphae,
what does long lived eukaryotic mycelium mean
n + n stage is long lived, 2 hap nuclei,
ectomycorrhizal
symbiotic with plant roots but extracellular spaces of root cortex
multicellular sexual reproduction of basidiomycota
fruiting body = basidiocarp (mushroom, puffball, bracket)
multicellular asexual reproduction basidiomycota
conidia formed by hyphae, — most reproduction is asexual
braket shelf fungi
grow in dying/dead woody organisms
fairy ring
formed because the fungus underground is digesting and growing outward.
how do basidiomycetes made sexual spores
on gills, by meiosis \, spores are presented in 4’s on a “pedestal” (basidium)
life cycle of basidiomycetes
4 meitotic spores (basidiospores) – spore dispersal/germination – mating types + and - — plasmogamy (typically occurs fruiting body is formed – dikaryotic mycelium – basidocarp (fruiting body), gills – sexual reproduction – basidia – karyogamy – diploid nuclei – meiosis – basidium – 4 spores
leaf cutter ants
fungus farmers – feeding leaves to fungus because they live on fungus, therefore farming it to maintain it.
ascomycota
biggest group, “sac” fungi, 65,000 species, multicellular or unicellular (yeast)
multicellular asexual repro: conidia
multicellular sexual repro: fruiting body = ascocarp
examples of ascomycetes
truffles, cup fungi, penicillin, blue cheese.
truffles
ectomyocorrhizae with trees – grown underground from oak tree roots.
asexual reproduction in ascomycetes
unicellular : yeast – budding – mother cell develops birth scars – one cell divides into two by mitosis
sexual reproduction of ascomycetes simple overview
asci – sacs
– each sac/ascus has 8 spores
– meiosis THEN mitosis
– meiosis – 4 spores – mitosis – 8 spores.
red bread mold cycle
sexual:
mating type – +/- — plasmogamy – dikaryotic – karyogam – zyogte – meiosis – mitosis – mature ascus – ascospores
asexual:
conidiophore – conidia – dispersal – germination – hypha –
ascomycete ; ergot alkaloids
grows on rye, ergots – restrict blood flow, body feels on fire, medical uses ; LSD
Candida albicans
gut flora, yeast/hyphal, transmitted from moth to chip at birth
botrytis
strawberries/grapes
aspergillus fumigatus
inhabit soils worldwide – we breathe -100
summary, phyla and features
chytids: flagellated spores
zygomycetes: resistant zygosporangium as sexual stage
glomeromycete: form arbuscular mycorrhizae with plants (fungi and plants work together)
ascomycetes: sexual spores (ascospores) born internally in sacs called asci; ascomycetes also produce vast number of asexual spores
basidiomycetes: elaborate fruiting body containing many basidia that produce sexual spores (basidiospore)
