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In the first the cell extends small pseudopods which then move down the sides of the cell, acting like paddles. [9] [10] [12] In the second the cell generates an internal flow cycle, with the cytoplasm flowing backward along the membrane edge and forward through the middle, generating a force on the membrane which moves the cell forward. [10] [12]
Cells which use flagella for movement are usually referred to as flagellates, cells which use cilia are usually referred to as ciliates, and cells which use pseudopods are usually referred to as amoeba or amoeboids. Other protists are not motile, and consequently have no built-in movement mechanism.
Acrasis kona is a eukaryotic microorganism within the family Acrasidae, notable for its life cycle that alternates between unicellular and multicellular stages. [1]In its unicellular phase, it exists as an amoeboid cell, while under certain environmental conditions, individual cells aggregate to form a multicellular structure. [2]
Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, [8] often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. [ 7 ] [ 9 ] In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista [ 10 ] or the kingdom ...
An amoeba (/ ə ˈ m iː b ə /; less commonly spelled ameba or amœba; pl.: amoebas (less commonly, amebas) or amoebae (amebae) / ə ˈ m iː b i /), [1] often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. [2]
The amoeboid stage can retract its filopodia and become a round cyst, in which palintomic cell division (i.e. rapid cell divisions without cytoplasmic growth in between, a characteristic of animal embryonic cleavage) [3] can occur, generating 2, 4, 8 or 16 flagellated cells that are released from inside the cyst.
In some cases the cell moves by "walking", with relatively permanent pseudopodia serving as limbs. The most important genera are Amoeba and Chaos, which are set apart from the others by longitudinal ridges. The best known of the species in this family is Amoeba proteus, commonly used in classrooms to demonstrate movement by pseudopodia.
[2] [3] [4] The axopodia are microtubule-supported projections from the amoeboid cell body, and are variously used for capturing food, sensation, movement, and attachment. They are similar to Radiolaria , but they are distinguished from them by lacking central capsules and other complex skeletal elements, although some produce simple scales and ...