Chapter 31: Fungi

Flashcards from Chapter 31 of Pearson's Campbell Biology, Twelfth Edition. LLM Disclaimer: These flashcards were created via several turns with Claude Sonnet 4.6 based off slide material.

Decomposers

Fungi that break down and absorb nutrients from nonliving organic material

• Recycles chemical elements between living and nonliving life

Parasitic fungi

Absorb nutrients from living hosts

• 30% of known fungi

• Causes 10–50% annual losses of world's fruit harvest

Mutualistic fungi

Absorb nutrients from host while providing a benefit

• Leaf-cutter ants grow fungi in farms, feeding them leaves, consume nutrient-rich hyphal tips.

Mold reproduction

Done through the production of haploid spores by mitosis

• Forms visible furry mycelia

• Spores are dispersed by wind or water to in moist environments

• May also be done without a partner with internal meiosis of spores to be released later on

Yeast budding

Reproduction of yeasts by simple cell division or by pinching off small bud cells

• No spores

Saccharomyces cerevisiae (insulin yeast)

Model yeast studied in stages of budding

• Genetically modified to produce human glycoproteins, including an insulin-like growth factor

Cryptomycetes

Phylum that is basal, unicellular, global in soils and aquatic habitats

• Many parasitize protists and other fungi

• Have flagellated spores and chitin-rich cell walls

Microsporidians

Phylum with unicellular parasites of protists and animals

• Has reduced mitochondria

• Infects hosts via harpoon-like organelle for reproduction

Chytrids

Phylum in aquatic and soil habitats

• Nearly all have flagellated zoospores

• Includes decomposers, parasites, and mutualists

Zoopagomycetes

Phylum with parasites or commensals of animals or fungi

• Has filamentous hyphae and nonflagellated wind-dispersed spores

• Some induce behavioral changes in parasitized insects

Ascomycetes

Phylum named “sac fungi” for saclike asci

• Includes plant pathogens, decomposers, yeasts, morels, and over 25% that form lichens

Deuteromycetes

Informal group of yeasts and filamentous fungi

• Reclassified when partner is discovered or genomic analysis places them in a phylum

Basidiomycetes

Phylum that includes mushrooms, puffballs, shelf fungi, rusts, smuts

• Some form fairy rings

• Best decomposers of lignin

Fairy rings

Rings of basidiomycetes appearing rapidly overnight

• The underlying mycelium expands outward about 30 cm per year

Hyphae

Tiny tubular filaments making up the body of most fungi

• Has cell walls strengthened with chitin, preventing lysis from osmotic pressure during nutrient absorption

Septa

Cross-walls dividing hyphae in most fungi into cells

• Contains pores large enough for cell-to-cell movement of organelles

Mycelium

An interwoven mass of hyphae infiltrating a food source

• Maximizes surface-to-volume ratio for efficient absorption

• Grows primarily in length via cytoplasmic streaming

Lichens

Symbiotic associations between photosynthetic microorganisms and fungi

• Held and structured within fungal hyphae with photosynthetic cells below surface

• Reproduces by fragmentation or forming soredia; fungal partner can also use partner

Pioneer lichens

Lichens that colonize new surfaces (volcanic flows, burned forests) by physically penetrating and chemically breaking them down

• Some fix nitrogen

• Likely helped pave the way for early plants

Claviceps purpurea (Ergot)

Ascomycete causing ergots on rye

• Toxins cause ergotism: gangrene, nervous spasms, burning sensations, hallucinations, temporary insanity

• However, they can also be used for reducing hypertension and childbirth maternal bleeding

Chytrid amphibian decline

Two chytrid species implicated in decline or extinction of ~500 amphibian species worldwide

• Causes severe skin infections leading to massive die-offs in frogs (e.g., yellow-legged frogs)

Candida albicans

Normal inhabitant of moist epithelia

• Can grow rapidly and become pathogenic under certain conditions, causing yeast infections in humans

Fungi uses

Includes:

• Cheese, alcohol, bread making

• Antibiotics (seen in penicillin)

• Medicine (with ergot and saccharomyces’ insulin-like growth factor)

• Biofuel (with Gliocladium roseum being studied)