Protist Studio — protozoans, algae and the protist toolkit
“Protist” is an informal term for a diverse group of microscopic eukaryotes — not a formal taxon, because they lack a shared evolutionary origin. Historically they are grouped as the “animal-like” protozoans, “plant-like” algae, and “fungus-like” protists such as water molds. Protozoans are nonphotosynthetic, motile and always unicellular; drifting protists are plankton (motile, nonphotosynthetic zooplankton vs photosynthetic phytoplankton). Explore the cell below — and use the encystment control to see a trophozoite become a cyst.
Amoebozoa Lab — crawl, invade, aggregate
The supergroup Amoebozoa moves by amoeboid movement: actin microfilaments push out pseudopodia and the protoplasm flows after them. Some members are medically important — and the slime molds (Eumycetozoa) put on one of biology’s strangest shows. Choose a mode.
Excavata Files — the reduced eukaryotes
The supergroup Excavata holds primitive eukaryotes and many parasites with limited metabolic abilities — organisms with complex cell shapes, often including a surface depression called an excavate. Its subgroups: Fornicata, Parabasalia and Euglenozoa.
Helminth Clinic — the worms in microbiology
Parasitic helminths are animals studied in microbiology because many species are identified by microscopic eggs and larvae. Two major groups: roundworms (Nematoda) and flatworms (Platyhelminthes) — about half of their species are parasitic. As animals they are multicellular with organ systems, but parasitic forms often have limited digestive tracts, nervous systems and locomotion; many have complex reproductive cycles with several life stages and more than one host. Some are monoecious (both sexes in one individual), others dioecious.
Fungi Lab — hyphae, budding and the dimorphic switch
Fungi are heterotrophic and typically saprozoic (feeding on dead organic matter). Microscopic yeasts and the spores of macroscopic fungi bring them into microbiology. They matter: decomposers, cheese-makers and penicillin factories — but also opportunistic pathogens causing mycoses mainly when immune defenses are compromised.
Algae Lab — pigments, endosymbiosis and blooms
Algae are autotrophic protists, unicellular or multicellular. They are ecologically critical: they produce roughly 70% of the oxygen and organic matter in aquatic environments — and they are the source of agar, agarose and carrageenan, the solidifying agents used in laboratories and food production. Typically not pathogenic, some produce toxins during harmful algal blooms.
Lichens — a fungus and a photobiont, together
A lichen is a combination of two organisms — a green alga or cyanobacterium and a fungus — living in a symbiotic relationship. While algae normally grow only in aquatic or very moist environments, lichens grow on almost any surface (especially rocks) or as epiphytes on other plants. They are classified as fungi, with partners from the Ascomycota and Basidiomycota.
Chapter Quiz — The Eukaryotes of Microbiology
Twenty-nine questions covering the whole chapter: protists and protozoans, amoebozoa, excavata, helminths, fungi, algae and lichens.