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Clockwise from top right: Amoeba proteus, Actinophrys sol, Acanthamoeba sp., Nuclearia thermophila., Euglypha acanthophora, neutrophil ingesting bacteria. 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 ...
In the process of evolution, single-celled organisms have developed in a variety of directions, and thus their rich morphology results in a large spectrum of swimming modes. [8] [2] Many swimming protists actuate tail-like appendages called flagella or cilia in order to generate the required thrust. [9]
Many different prokaryotic and eukaryotic cells can swim and many of these have either flagella or cilia for that purpose. These dedicated structures are not necessary for swimming, though, as there are amoeba and other eukaryotic cells which lack flagella and cilia but can still swim, although it is slower than crawling or gliding.
Those that feed on soluble molecules [129]: 218 or macromolecules under 0.5 μm in size are called osmotrophs, [128] and they absorb them by diffusion, ciliary pits, transport proteins of the cell membrane, and a type of endocytosis (i.e., invagination of the cell membrane into vacuoles, called endosomes) known as pinocytosis [2] or fluid-phase ...
Most ciliates are heterotrophs, feeding on smaller organisms, such as bacteria and algae, and detritus swept into the oral groove (mouth) by modified oral cilia. This usually includes a series of membranelles to the left of the mouth and a paroral membrane to its right, both of which arise from polykinetids , groups of many cilia together with ...
Ciliates (which move by using hair-like structures called cilia) and amoebae (which move by the use of temporary extensions of cytoplasm called pseudopodia). Many protozoa, such as the agents of amoebic meningitis, use both pseudopodia and flagella. Some protozoa attach to the substrate or form cysts, so they do not move around . Most sessile ...
An amoeba of the genus Mayorella (Amoebozoa, Discosea) Amoebozoa is a large and diverse group, but certain features are common to many of its members. The amoebozoan cell is typically divided into a granular central mass, called endoplasm, and a clear outer layer, called ectoplasm. During locomotion, the endoplasm flows forwards and the ...
Enclosing the cell is the cell envelope, generally consisting of a plasma membrane covered by a cell wall which, for some bacteria, may be further covered by a third layer called a capsule. Though most prokaryotes have both a cell membrane and a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermoplasma (archaea) which only ...