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A flagellum (/ f l ə ˈ dʒ ɛ l əm /; pl.: flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores (), and from a wide range of microorganisms to provide motility.
Flagella are generally used for propulsion. They may also be used to create a current that brings in food. In most such organisms, one or more flagella are located at or near the anterior of the cell (e.g., Euglena). Often there is one directed forwards and one trailing behind.
The arrangement of flagella about the bacterial cell is unique to the species observed. Common forms include: Monotrichous – Single flagellum; Lophotrichous – A tuft of flagella found at one of the cell poles; Amphitrichous – Single flagellum found at each of two opposite poles; Peritrichous – Multiple flagella found at several ...
Typically, one flagellum is very short, and does not protrude from the cell, while the other is long enough to be seen with light microscopy. In some species, such as Euglena mutabilis, both flagella are "non-emergent"—entirely confined to the interior of the cell's reservoir—and consequently cannot be seen in the light microscope.
Basal bodies originate from and have a substructure similar to that of centrioles, with nine peripheral microtubule triplets (see structure at bottom center of image). A basal body (synonymous with basal granule , kinetosome , and in older cytological literature with blepharoplast ) is a protein structure found at the base of a eukaryotic ...
The transverse flagellum is structurally complex and wraps around the cingulum. [2] The movement of the flagellum is described as "wave-like" and allows the organism to spin as it swims. [2] The longitudinal flagellum extends from a groove known as the sulcus, and this flagellum is simpler in structure than the transverse flagellum. [2]
One flagellum is relatively long and conspicuous, and when the Peranema is gliding it is held stiffly in front. At the tip of the flagellum, a short segment beats and flails in a rhythmic manner, possibly as a mechanism for detecting and contacting potential prey. Peranama usually glides belly-down, without rotating. [13]
First, the basal bodies and flagella replicate, then the cytostome and microtubules (the feeding apparatus), and finally the nucleus and remaining cytoskeleton. Once this occurs, the organism begins to cleave at the basal bodies, and this cleavage line moves towards the center of the organism until two separate euglenids are evident. [ 20 ]