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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. The flagella in eukaryotes have dynein and microtubules that move with a bending mechanism. Bacteria and archaea do not have dynein or microtubules in ...
The bacterial flagellum consists of three basic components: a whip-like filament, a motor complex, and a hook that connects them. The filament is approximately 20 nm in diameter and consists of several protofilaments, each made up of thousands of flagellin subunits.
[14] [3] During the rotation of the bacterial flagellar motor, which is located in the membrane, the flagella rotate at speeds between 200 and 2000 rpm, depending on the bacterial species. The hook substructure of the bacterial flagellum acts as a universal joint connecting the motor to the flagellar filament. [13]
Flagellins are a family of proteins present in flagellated bacteria [1] which arrange themselves in a hollow cylinder to form the filament in a bacterial flagellum. Flagellin has a mass on average of about 40,000 daltons. [2] [3] Flagellins are the principal component of bacterial flagella that have a crucial role in bacterial motility.
Inside a cilium and a flagellum is a microtubule-based cytoskeleton called the axoneme. The axoneme of a primary cilium typically has a ring of nine outer microtubule doublets (called a 9+0 axoneme), and the axoneme of a motile cilium has two central microtubules in addition to the nine outer doublets (called a 9+2 axoneme).
[2]: 396 The bacterial flagellum is the best known example. [27] [28] About half of all known bacteria have at least one flagellum; thus, given the ubiquity of bacteria, rotation may in fact be the most common form of locomotion used by living systems—though its use is restricted to the microscopic environment. [29]
The evolution of flagella is of great interest to biologists because the three known varieties of flagella – (eukaryotic, bacterial, and archaeal) each represent a sophisticated cellular structure that requires the interaction of many different systems.
The bacterial flagellum is made of about 20 proteins, with approximately another 30 proteins required for its regulation and ... as part of the three-domain system. [5]