Types
Three types of flagella have so far been distinguished; bacterial, archaeal and eukaryotic.
The main differences among these three types are summarized below:
- Bacterial flagella are helical filaments, each with a rotary motor at its base which can turn clockwise or counterclockwise. They provide two of several kinds of bacterial motility.
- Archaeal flagella (Archaella) are superficially similar to bacterial flagella, but are different in many details and considered non-homologous.
- Eukaryotic flagella - those of animal, plant, and protist cells - are complex cellular projections that lash back and forth. Eukaryotic flagella are classed along with eukaryotic motile cilia as undulipodia to emphasize their distinctive wavy appendage role in cellular function or motility. Primary cilia are immotile, and are not undulipodia; they have a structurally different 9+0 axoneme rather than the 9+2 axoneme found in both flagella and motile cilia undulopodia.
Read more about this topic: Flagellum
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