NEET BIOLOGY

Detailed explanation-1: -The bacterial flagellum is a helical filamentous organelle responsible for motility. In bacterial species possessing flagella at the cell exterior, the long helical flagellar filament acts as a molecular screw to generate thrust.

Detailed explanation-2: -The flagellum has three components-the motor, hook, and filament. The rotation of the filament allows bacteria to move around in their environment. The motor embedded in the bacterial cell membrane rotates-just as a car motor spins beneath the hood of the vehicle-to drive the movement of the filament outside.

Detailed explanation-3: -Flagellum is primarily a motility organelle that enables movement and chemotaxis. Bacteria can have one flagellum or several, and they can be either polar (one or several flagella at one spot) or peritrichous (several flagella all over the bacterium).

Detailed explanation-4: -The movement of eukaryotic flagella depends on adenosine triphosphate (ATP) for energy, while that of the prokaryotes derives its energy from the proton-motive force, or ion gradient, across the cell membrane.

Detailed explanation-5: -A flagellum is built on a template organelle called the basal body, which is constructed by modifying a centriole recruited from a centrosome (or from a pre-existing basal body) (Figure 1).