Topic 8 -Fungi Flashcards
How do fungi influence our everyday lives?
Food products -cheese, wine, bread, mushrooms
plant, insect & animal pathogens -ring worm, potato blight, biocontrol
pharmacy -penicillin
List the defining characteristics of fungi
eukaryotic
Chemoheterotrophic
does NOT contain chlorophyll
Reproduces via spores
obtains nutrients via absorption
cell wall composed of chitin (no peptidoglycan)
can tolerate low moisture conditions, high osmotic pressure & acidic environments (pH 5.0)
Multicellular (filamentous or unicellular)
briefly describe chemoheterotrophic absorption
fungi get carbon from organic sources
hypha tips release enzymes
enzymatic breakdown of substrate
products diffuse back into hyphae
Describe the structures of fungi
Thallus -body composed of tube-like cells called hyphae
Mycelium -meshwork of hyphae
Hyphae are haploid
Saprophytes/saprobes -exoenzymes break down substrate for absorption
Fungal hyphae grow from the…. & the two types of hypha are… &…
grow from the tip (nuclei move into tip -vegetative growth)
2 types: septate hypha (segmented) & coenocytic hypha (single tube).
A little about yeasts?
unicellular fungi
fission yeasts -divide symmetrically
budding yeasts -divide asymmetrically
What is fungal dimorphism?
fungi change from yeast-like to mould-like depending on CO2 concentration or temperature
What does asexual repro in fungi involve?
Mitosis only -spores are genetically identical
What does sexual repro in fungi involve?
3 phases:
Plasmogamy: cytoplasm of 2 parent cell hyphae fuse; + hypha penetrates cytoplasm of recipient - hypha.
Karyogamy: nuclei from each + & - hyphae now are in same cytoplasm & fuse
Meiosis: resulting diploid nucleus produces haploid nuclei which become the nuclei of the sexual spores
Name the 5 different kinds of fungi
Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes
A bit about spores? Which ones are sex or asex?
Asex -sporangio, conidia (some), zoospores
Sex -asco, basidio, zygo, zoospores
Spores are important in fungal classification
A bit about chytrids?
most primitive
Spread via swimming zoospores w/ flagella
Vegetative growth -hyphae
Can be parasitic
A bit about zygomycetes?
Non-motile spores produce asex sporangiospores produce sex zygospores \+ & - hyphae fuse to give diploid spore Vegetative growth -hyphae Conjugation fungi -fusion of 2 hyphae from different strains of same fungus Coenocytic (aseptate=no cross walls)
A bit about glomeromycetes?
Form mutualistic associations w/ plants (mycorrhizal)
Very important for plant growth! -plant supplies sugar to fungus, fungus gets phosphorous for plant & increase root SA
A bit about ascomycetes?
Sac fungi (biggest phylum)
Septate (cross walls)
Spores are non-motile: ascospores or conidiospores
