Fungi: Structure, function and ecosystem

Flashcards covering fungal structure, reproduction, major clades, ecological roles, and human impacts based on lecture notes.

Fungi

Heterotrophs that feed by absorption, breaking down organic material and recycling nutrients to allow other organisms to assimilate essential chemical elements.

Hydrolytic enzymes

Enzymes used by fungi to break down complex molecules into smaller organic compounds, capable of digesting materials from living or dead sources.

Decomposers

Fungi that break down and absorb nutrients from nonliving organic material.

Parasitic fungi

Fungi that absorb nutrients from living hosts.

Mutualistic fungi

Fungi that absorb nutrients from hosts and reciprocate with actions that benefit the host.

Yeasts

Single-celled fungal structures that inhabit moist environments with plentiful soluble nutrients, such as sugars or amino acids.

Hyphae

Tiny filaments that form fungal bodies, featuring tubular cell walls strengthened with chitin.

Chitin

A structural polymer that strengthens fungal cell walls and prevents cells from lysing due to osmotic pressure during nutrient absorption.

Septa

Cross-walls in hyphae that divide them into cells, containing pores large enough to enable cell-to-cell movement of organelles.

Coenocytic fungi

Fungi that lack septa and consist of a continuous cytoplasmic mass containing hundreds or thousands of nuclei resulting from repeated division without cytokinesis.

Mycelium

An interwoven mass of fungal hyphae that infiltrates the food source and maximizes surface-to-volume ratio for efficient absorption.

Haustoria

Specialized hyphae that allow fungi to extract nutrients from plants.

Arbuscules

Specialized branching hyphae used to exchange nutrients with plant hosts by penetrating plant cell walls but not the cell membrane.

Mycorrhizae

Mutually beneficial relationships between fungi and plant roots where fungi deliver phosphate ions and minerals in exchange for organic nutrients.

Ectomycorrhizal fungi

Fungi that form sheaths of hyphae over the root surface and extend into the extracellular spaces of the root cortex.

Arbuscular mycorrhizal fungi

Fungi that extend arbuscules through the root cell wall and into tubes formed by invagination of the root cell plasma membrane.

Spores

Haploid cells used for fungal dispersal and propagation, carried long distances by wind or water before germinating into new mycelia.

Pheromones

Sexual signaling molecules used by fungi to communicate mating types during sexual reproduction.

Plasmogamy

The union of cytoplasm from two parent mycelia.

Heterokaryon

A mycelium that contains coexisting, genetically different nuclei after plasmogamy.

Dikaryotic

A mycelium in which haploid nuclei pair off two to a cell, one from each parent, without fusing immediately.

Karyogamy

The stage where haploid nuclei fuse to produce diploid cells or zygotes.

Molds

Fungi that produce haploid spores asexually by mitosis and form visible, furry mycelia.

Deuteromycetes

A group of yeasts and filamentous fungi that have no known sexual stage.

Opisthokonts

A clade including fungi, animals, and their protistan relatives, which evolved from a unicellular flagellated ancestor.

Nucleariids

Single-celled protist amoebas that feed on algae and bacteria and are more closely related to fungi than to animals.

Tortotubus

A fungus from which fossil hyphae dating back to $440\,million$ years ago were discovered.

Cryptomycetes

A basal fungal lineage of unicellular fungi with flagellated spores that can synthesize a chitin-rich cell wall.

Microsporidians

Unicellular parasites of protists and animals that have highly reduced mitochondria and infect host cells via a harpoon-like organelle.

Chytrids

Fungi characterized by flagellated spores called zoospores, found in lakes, soil, and marine habitats.

Zoopagomycetes

Fungi that live as parasites or commensal symbionts, forming filamentous hyphae and producing durable zygosporangia during sexual reproduction.

Zygosporangium

A durable structure that houses and protects the zygote, often resistant to freezing and drying.

Mucoromycetes

A phylum including fast-growing molds like Rhizopus stolonifer and arbuscular forming fungi called glomeromycetes.

Ascomycetes

Often called sac fungi, this group produces spores in saclike asci and includes cup fungi, morels, and many lichen-forming species.

Ascocarps

Fruiting bodies produced by ascomycetes during the sexual stage which contain the spore-forming asci.

Conidia

Asexual spores produced by ascomycetes externally at the tips of specialized hyphae called conidiophores.

Basidiomycetes

Also known as club fungi, this group includes mushrooms and puffballs and is named for the basidium, a cell where karyogamy and meiosis occur.

Basidiocarps

Sexual fruiting bodies of basidiomycetes, such as common mushrooms, that protect a large surface area of dikaryotic basidia on gills.

Lignin

A complex polymer abundant in wood that certain basidiomycetes are highly efficient at decomposing.

Endophytes

Symbiotic fungi or bacteria that live inside leaves or other plant parts without causing harm, often producing toxins to defend the host.

Lichens

Symbiotic associations between photosynthetic microorganisms (green algae or cyanobacteria) and fungi, typically ascomycetes.

Soredia

Small clusters of fungal hyphae with embedded algae used for the asexual reproduction of lichens.

Ergots

Structures grown on rye caused by the ascomycete Claviceps purpurea, which contain toxins that cause gangrene and hallucinations in humans.

Mycosis

The general term for a fungal infection in animals, such as ringworm or athlete's foot.

Coccidioidomycosis

A potentially fatal systemic mycosis that produces tuberculosis-like symptoms in the lungs.

Candida albicans

A normal inhabitant of moist epithelia that can become pathogenic and cause yeast infections under certain conditions.

Penicillium

An ascomycete fungus used to produce penicillin, an antibiotic for treating bacterial infections.

Saccharomyces cerevisiae

A yeast genetically modified to produce human glycoproteins, including insulin-like growth factor.