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The prokaryotic flagellum uses a rotary motor, and the eukaryotic flagellum uses a complex sliding filament system. Eukaryotic flagella are ATP-driven, while prokaryotic flagella can be ATP-driven (Archaea) or proton-driven (Bacteria). [11] The three types of flagella are bacterial, archaeal, and eukaryotic.
As such, the type three secretory system supports the hypothesis that the flagellum evolved from a simpler bacterial secretion system. However, the true relationship could be the reverse: recent phylogenetic research strongly suggests the type three secretory system evolved from the flagellum through a series of gene deletions. [7]
The only known example of a biological "wheel" or "propeller"—a system capable of providing continuous propulsive torque about a fixed body—is the flagellum, a corkscrew-like tail used by single-celled prokaryotes for propulsion. [2]: 396 The bacterial flagellum is the best known example.
Eukaryotic flagella are complex cellular projections that lash back and forth, rather than in a circular motion. Prokaryotic flagella use a rotary motor, and the eukaryotic flagella use a complex sliding filament system. Eukaryotic flagella are ATP-driven, while prokaryotic flagella can be ATP-driven (archaea) or proton-driven (bacteria). [22]
Many bacteria, such as Vibrio, are monoflagellated and have a single flagellum at one pole of the cell. Their method of chemotaxis is different. Others possess a single flagellum that is kept inside the cell wall. These bacteria move by spinning the whole cell, which is shaped like a corkscrew. [25] [page needed]
Flagella in eukaryotes are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body. In some flagellates, flagella direct food into a cytostome or mouth, where food is ingested. Flagella role in classifying eukaryotes.
Behe's original examples of irreducibly complex mechanisms included the bacterial flagellum of E. coli, the blood clotting cascade, cilia, and the adaptive immune system. Behe argues that organs and biological features which are irreducibly complex cannot be wholly explained by current models of evolution .
Eukaryotic flagella are complex cellular projections that lash back and forth, rather than in a circular motion. Prokaryotic flagella use a rotary motor, and the eukaryotic flagella use a complex sliding filament system. Eukaryotic flagella are ATP-driven, while prokaryotic flagella can be ATP-driven (archaea) or proton-driven (bacteria). [124]