fungi Flashcards
fungi
essential for the ecosystem. extremely diverse and widespread.
number of species of fungi
100K described, 1.5 million undiscovered
fungi nutrition
heterotrophic. feed by absorption. spores land on food and digest it
key to fungi ecological success
enzyme versatility
fungi lifestyles
decomposers, parasites, mutualistic symbionts
decomposer
breaks down and absorbs nutrients from non-living organisms.
parasites
negative type of symbiotic relationship. parasite wins, the host loses. absorb nutrients from living host. causes fungal disease. 80% of plant diseases are fungal
mutualistic symbionts
fungus and host win. swap nutrients. reciprocal interaction.
body structures
the majority are multicellular filamentous, some are unicellular
yeast
single-celled fungi. least common morphology. live in moist environments
filamentous
white fuzzy stuff. multicellular vegetative body. morphology enhances the ability to absorb nutrients- it’s flat and increases surface area.
filament
hyphae
mycelium
an interwoven mat of hyphae
cell wall
made of chitin, keeps the cells from exploding water
reproductive structures
only present at certain times
septate hyphae
hyphae contain septa, there is division. multicellular type of organism. pores between cell walls that allow nutrients to transfer.
coenocytic hyphae
one big cytoplasm, no separation. lots of nuclei everywhere. single-celled organism. dynamic
mycorrhizal fungi
win-win situation. mutualism between fungi and plants. fungi provide the minerals, plants provide the organic nutrients.
ectomycorrhizal fungi
the fungus is on the outside of the root and goes in between the cells. forms sheets of hyphae over the roots, does not penetrate the epidermal cell. grows between the extracellular spaces. looks like white fuzzy stuff.
arbuscular fungi
most common. hyphae puncture into the epidermal cell of the root, doesn’t harm it. branching hyphae penetrate the cell wall. associated with the internal cytoplasm. resembles motor endplates in animals.
reproduction
produce spores to propagate themselves
sexual
the diploid zygote state is transitional. the fusion of hyphae from different mating types (positive or negative). signal each other through pheromones, avoid the same mating types. fungi can avoid their own mating types to increase genetic diversity.
plasmogamy
the fusion of the cytoplasm of 2 hyphae of different mating types.
heterokaryon
2 separate haploid nuclei
dikaryon stage
delay in the fusion of nuclei
karyogamy
the fusion of the 2 nuclei. sexual reproduction. forms the diploid zygote. the part that increases genetic variation.
zygote undergoes meiosis
formation and release of haploid spores. spores then make new mycelium, mycelium can produce fruiting bodies or mate with another hypha.
asexual reproduction
in the haploid state, the sporangia produce haploid spores. spores are released into the environment and make the next mycelia
yeast
only asexual reproduction: budding or simple cell division
fungi ancestor
aquatic single-celled flagellate protist
opisthokonts
protists, fungi & animals
order of colonization
prokaryote (cyanobacteria), algae, fungi
sym genes
specialized genes in plants that have been conserved for hundreds of millions of years that allow plants to form a mycorrhizal association with fungi without being harmed
5 major fungi groups
chytrids, zygomycetes, glomeromycetes, ascomycetes, basidiomycetes
chytrids
1,000 species. Basal fungi, everybody else went a different direction. sister taxa to all other fungi. maintained the flagellate state: spores swim, called zoospores. the flagellate stage has to be in water or moist soil. parasites, mutualists, decomposers
