Diversity of Microbial Life: Eukaryotes – Protists & Fungi

Vocabulary flashcards covering the diversity, classification, and ecological importance of eukaryotic protists and fungi based on the lecture material.

Protists

A catch-all term for eukaryotes that are not classified in the plant, animal, or fungal kingdoms, often microscopic and most abundant in moist habitats.

Algae

An informal classification of typically photoautotrophic protists that produce organic compounds and $O_2$.

Protozoa

An informal classification of heterotrophic protists that feed by absorbing small organic molecules or by ingesting prey.

Fungus-like protists

Protists that possess bodies, nutrition, or reproduction mechanisms similar to those found in the kingdom Fungi.

Flagellates

Protists that swim by means of one or a few flagella.

Ciliates

Protists that use many cilia to move through their environment.

Amoebae

Protists that move by extending their cytoplasm into lobes called pseudopodia.

Phytoplankton

Microscopic photosynthetic protists that swim or float in fresh or salt water.

Periphytic protists

Protists that attach themselves to underwater surfaces such as rocks, sand, and plants, forming communities called periphyton.

Seaweeds (macroalgae)

Large photosynthetic protists that usually grow attached to underwater surfaces.

Excavata

A eukaryotic supergroup named for a feeding groove that allows food particles to be ingested by phagocytosis; it includes organisms like euglenoids and various parasites.

Phagocytosis

The process by which a cell ingests food particles, which also serves as the evolutionary basis for endosymbiosis.

Trichomonas vaginalis

A parasitic member of the Excavata supergroup that causes a sexually transmitted disease called trichomoniasis.

Giardia intestinalis

A plastidless member of the Excavata supergroup that causes the symptoms of giardiasis.

Rhodophyta

A phylum of red algae within the Land Plants and Related Algae supergroup, characterized by distinctive photosynthetic pigments and typically multicellular marine forms.

Alveolata

A eukaryotic supergroup named for the presence of saclike, membranous vesicles called alveoli at the cell periphery.

Dinozoa (dinoflagellates)

A phylum of Alveolata known for mutualistic relationships with reef-building corals and for causing harmful red tide blooms.

Apicomplexa

A medically important group of Alveolata that are obligate parasites, including the agents that cause malaria.

Plasmodium

A genus of Apicomplexans that infects red blood cells and requires two alternate hosts: humans (or great apes) and Anopheles mosquitoes.

Primary endosymbiosis

The evolutionary process where a eukaryotic cell without a plastid engulfs a cyanobacterial cell, resulting in a primary plastid with a double-membrane envelope.

Secondary endosymbiosis

The process where a host cell acquires a eukaryotic endosymbiont that already contains one or more primary plastids, such as a red or green alga.

Tertiary endosymbiosis

The process involving a host cell acquiring a eukaryotic endosymbiont that possesses secondary plastids.

Stramenopila

A eukaryotic supergroup characterized by distinctive straw-like hairs on their flagella, including diatoms and brown algae.

Diatoms

Unicellular stramenopiles with two-piece cell walls of silicon dioxide that perform approximately $\frac{1}{5}$ of all carbon fixation on Earth.

Brown algae (Kelps)

Multicellular marine stramenopiles that can grow up to $60\,m$ long and use holdfasts with alginic acid to attach to surfaces.

Rhizaria

A eukaryotic supergroup consisting of several flagellates and amoebae that possess thin, hair-like extensions of the cytoplasm called filose pseudopodia.

Foraminifera

A phylum within Rhizaria that produces calcium carbonate shells; their accumulation has produced much of the world's limestone.

Amoebozoa

A eukaryotic supergroup that includes many types of amoebae and slime molds which move by extending pseudopodia.

Dictyostelium discoideum

A slime mold used as a model organism to understand cell communication, development, and the evolution of multicellularity.

Opisthokonta

The eukaryotic supergroup that includes the animal and fungal kingdoms, named for the presence of a single posterior flagellum on swimming cells.

Choanoflagellates

The closest living protist relatives of animals, belonging to the supergroup Opisthokonta.

Chitin

A polysaccharide long-chain polymer of N-acetylglucosamine that strengthens fungal cell walls and allows them to resist osmotic pressure.

Absorptive heterotrophy

The fungal nutrition method where digestive enzymes are secreted outside the body and small digested molecules are then absorbed.

Saprobes

Organisms that act as decomposers by absorbing nutrients from dead organic matter.

Hyphae

Root-like filaments used by multicellular fungi to digest food; they can be septate (subdivided by walls) or aseptate (coenocytic).

Mycelium

A mass of hyphae that makes up the body of a fungus, characterized by a large surface area to volume ratio.

Fruiting body

The visible reproductive structure of a fungus that contains and disperses reproductive spores.

Conidia

Asexual spores produced at the tips of fungal hyphae that allow for rapid spread and colonization.

Glomeromycota

A fungal phylum known as arbuscular mycorrhizal (AM) fungi that form mutually beneficial associations with plant roots.

Ascomycetes

A fungal group that produces nonflagellate sexual spores called ascospores in sac-like structures called asci.

Basidiomycetes

A fungal group characterized by the production of basidiospores on club-shaped structures called basidia.

Lichens

A symbiotic association between a fungus (usually an Ascomycota) and a photosynthetic partner such as a green alga or cyanobacteria.

Arbuscular Mycorrhizae

Mutualistic associations where fungal hyphae penetrate root cell walls to form treelike structures inside the cell wall but outside the plasma membrane.

Ectomycorrhizae

Mutualistic associations where fungal hyphae wrap around individual cells in the root but do not penetrate them.

Bioremediation

The technological application of microbes to break down organic compounds for treating wastewater, industrial discharge, or oil spills.