| Term | Definition |
| alga | historical term for photosynthetic protists - not accepted by all scientists |
| alternation of generations | life cycle in which a haploid gamete-producing individual (gametophyte) alternated with a diploid spore-producing individual (sporophyte) |
| amoeba | protist that moves using flexible, cytoplasmic extensions |
| cilium | in cells, one hair like structure in tightly packed rows that are used for movement |
| diatom | photosynthetic unicellular protist of the phylum Bacillariophyta |
| euglenoid | members of the phylum Euglenophyta |
| merozoite | stage of the life cycle of the protist Plasmodium in which the protist divides rapidly in red blood cells and produces many more merozoites |
| plasmodium | protist of the phylum Myxomycota; characterized by multinucleate, amoeboid appearance |
| protozoan | historic term for a heterotrophic protist |
| pseudopodium | extension of cytoplasm of the amoeba that enables it to move |
| sporangium | spore capsule in which haploid spores are produced by meiosis |
| sporozoite | one of three stages of Plasmodium that lives in mosquitoes and is injected into human |
| zoomastigote | unicellular, heterotrophic protist that is a member of the phylum Zoomastigina |
| zygospore | diploid zygote that results from the pairing of gametes of the opposite mating types |