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Wheel-like appendage ?


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Hi.

Is there any living organism with a wheel+shaft-like appendage ?

 

There is feathers, cilia, tails, joints, paws, hooks, scales, wings, hair, and dozens more, but seems mother nature has not invented the wheel.

 

 

yes there is a biological wheel + shaft.

 

 

629px-Flagellum_base_diagram_en.svg.png

Wheel-like rotation

 

Though no known multicellular organism is able to spin part of its body freely relative to another part of its body, there are two known examples of rotating molecular structures used by living cells.[

 

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The only known example of a biological "wheel", a system capable of providing continuous propulsive torque about a fixed body, is the flagellum, a propeller-like tail used by single-celled prokaryotes for propulsion. The bacterial flagellum is the best known example.[6][18] About half of all known bacteria have at least one flagellum, indicating that rotation may in fact be the most common form of locomotion in living systems.[19]

 

At the base of the bacterial flagellum, where it enters the cell membrane, a motor protein acts as a rotary engine. The engine is powered by proton motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane due to a concentration gradient set up by the cell's metabolism. (In species of the genus Vibrio, there are two kinds of flagella, lateral and polar, and some are driven by a sodium ion pump rather than a proton pump.)[20] Flagella are quite efficient, allowing bacteria to move at speeds up to 60 cell lengths per second. The rotary motor at the base of the flagellum is similar in structure to that of ATP synthase.[14] Spirillum bacteria have helically-shaped bodies with flagella at either end, and spin about the central axis of their helical body as they move through the water.[21]

 

Archaea, a group of prokaryotes distinct from bacteria, also feature flagella driven by rotary motor proteins, though they are structurally and evolutionarily distinct from bacterial flagella. Whereas bacterial flagella evolved from the bacterial Type III secretion system, archaeal flagella appear to have evolved from Type IV pili.[22] Some eukaryotic cells, such as the protist Euglena, also have a flagellum, but eukaryotic flagella do not rotate at the base; rather, they bend in such a way that the tip of the flagellum whips in a circle. The eukaryotic flagellum, also called a cilium or undulipodium, is structurally and evolutionarily distinct from prokaryotic flagella.[23]...

 

Rotating locomotion in living systems

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