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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 their flagella, and they move using a rotary mechanism. [12] Other differences among these three types are:
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.
Examples range from the propulsion of single cells such as the swimming of spermatozoa to the transport of fluid along a stationary layer of cells such as in a respiratory tract. Though eukaryotic flagella and motile cilia are ultrastructurally identical, the beating pattern of the two organelles can be different.
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.
Many eukaryotes have long slender motile cytoplasmic projections, called flagella, or multiple shorter structures called cilia. These organelles are variously involved in movement, feeding, and sensation. They are composed mainly of tubulin, and are entirely distinct from prokaryotic flagella.
Examples range from the propulsion of single cells such as the swimming of spermatozoa to the transport of fluid along a stationary layer of cells such as in a respiratory tract. Though eukaryotic flagella and motile cilia are ultrastructurally identical, the beating pattern of the two organelles can be different.
Other examples are the dictyostelians, another group of slime molds, [11] and the closely related varioseans, such as Phalansterium. [7] Breviatea, a small class [a] related to animals, fungi and amoebozoans, is composed of anaerobic amoeboflagellates with two flagella. [13] [14]
It is this feature that gives the group its name. In contrast, flagellate cells in other eukaryote groups propel themselves with one or more anterior flagella. Flagellate cells however have been secondarily lost in some opisthokont groups, including most of the fungi. [7]