Microbiology Chapter 12: Fungi, Algae, and Lichens

Vocabulary terms and definitions covering fungal characteristics, reproduction, classification, and industrial/medical relevance, as well as lichens and algae.

Mycology

The study of fungi.

Chemoheterotrophs

Organisms that require organic compounds for both energy and carbon sources.

Ergosterols

Specific sterols found in fungal cell membranes that help with membrane permeability.

Thallus

The body of a mold or fleshy fungus, consisting of long filaments of cells joined together.

Hyphae

Long filaments of cells that make up the thallus of a fungus.

Septate hyphae

Fungal hyphae that contain cross-walls.

Coenocytic hyphae

Fungal hyphae that do not contain separations in the cell wall.

Vegetative hyphae

The portion of hyphae responsible for obtaining nutrients.

Aerial hyphae

The portion of hyphae that bears reproductive spores.

Yeasts

Non-filamentous, unicellular fungi that are typically spherical or oval.

Dimorphic Fungi

Fungi that exhibit two forms of growth, appearing as yeast at $37^\text{o}C$ and mold at $25^\text{o}C$.

Conidia

Asexual fungal spores that are not enclosed in a sac and are arranged in chains at the end of a conidiophore.

Sporangiospore

Asexual fungal spores formed within a sac called a sporangium.

Plasmogamy

A phase of sexual reproduction where a haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-).

Karyogamy

The phase of sexual reproduction where (+) and (-) nuclei fuse to form a diploid zygote nucleus.

Meiosis

The phase where a diploid nucleus gives rise to haploid nuclei, which serve as sexual spores.

Zygospore

A large sexual spore enclosed in a thick wall, characteristic of the phylum Zygomycota.

Ascus

A saclike structure in Ascomycota that houses sexual spores known as ascospores.

Basidium

A base pedestal on which basidiospores are formed externally in the phylum Basidiomycota.

Valley Fever

A serious respiratory infection caused by the Ascomycota fungus Coccidioides immitis, endemic to the American southwest.

Aflatoxins

Potent biological carcinogens produced by Aspergillus flavus, often found in contaminated nuts, grains, and rice.

Mycosis

The general term for a fungal infection.

Lichen

A mutualistic combination of a green alga (or cyanobacterium) and a fungus.

Crustose

A type of lichen growth form that appears encrusted on the substratum.

Algin

A thickener used in foods that is produced from the cellulose and alginic acid cell walls of brown algae.

Diatoms

Unicellular or filamentous algae with pectin and silica cell walls that store energy as oil.

Saxitoxins

Neurotoxins produced by dinoflagellates that can make shellfish poisonous to humans.

Algal Blooms

Periodic increases in planktonic algae that can result in toxin release or oxygen depletion when the algae die.