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Pseudopod
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Pseudopods or pseudopodia (singular: pseudopodium) (from the Greek word ?e?d?p?d?a, ?e?d?? "fake, false" + p?d?a "feet") are temporary projections of eukaryotic cells. Cells having this faculty are generally referred to as amoeboids. Pseudopodia extend and contract by the reversible assembly of actin subunits into microfilaments.
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Encyclopedia
eruses4|eukaryotic cells|the Band|Pseudopod (band)}}
Pseudopods or pseudopodia (singular: pseudopodium) (from the Greek word ?e?d?p?d?a, ?e?d?? "fake, false" + p?d?a "feet") are temporary projections of eukaryotic cells. Cells having this faculty are generally referred to as amoeboids. Pseudopodia extend and contract by the reversible assembly of actin subunits into microfilaments. Filaments near the cell's end interact with myosin which causes contraction. The pseudopodium extends itself until the actin reassembles itself into a network. This is how amoebas move, as well as some cells found in animals, such as white blood cells.
Reproduction
First and foremost, the cell surface extends a membrane process, termed a lamellipodium. Polymerization of actin takes place and form filaments at the leading edge, which subsequently will blend into one another to form networks. It is supposed that actin polymerization is at the origin of the force propelling the cell forwards.
Pseudopodia (which translates to "false feet") are temporary cytoplasm-filled projections of the cell wall that certain eukaryotic cells use for motion or for ingesting nutrients. Most cells with this capability are referred to as amoeboids.
Pseudopodia are formed by microtubule and filament structures. The cell surface projects a membrane process called the lamellipodium, which is supported inside by filaments that form at the leading edge, turning into networks as they blend together. Cytoplasm flows into the lamelliopdium, forming the pseudopodia.
The functions of pseudopodia include locomotion and the capturing of prey. Pseudopodia are critical in sensing prey that can then be engulfed; the engulfing pseudopodia are called phagocytosis pseudopodia. A common example of this sort of amoeboid cell is the human white blood cell.
Pseudopodia don't all look like amorphous blobs; instead, they can be classified by their distinct appearances. Lobopodia are bulbous and amoebic. Filopodia are slender, sort of football shaped, and are supported largely by microfilaments. Reticulopodia are very complex and bear individual pseudopodia that form irregular nets. Axopodia are the phagocytosis type, with long thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm, and they respond rapidly to physical contact.
Function
Mechanical role
Pseudopods are one of the three locomotion modes of unicellular organisms (together with flagella and cilia).
Pseudopods are also important in cell signaling, angiogenesis and phagocytosis.
Morphology
Pseudopods can be classified into several varieties according to their appearance:
- Lobopodia are bulbous, short and blunt in form, very typical of Amoebozoa.
- , also known as reticulose pseudopods, are complex formations where individual pseudopods are blended together and form irregular nets.
- Axopodia are thin pseudopods containing complex arrays of microtubules and are enveloped by cytoplasm. Axopodia are mostly responsible for phagocytosis, by rapidly retracting in response to physical contacts. They are observed in radiolaria and heliozoa. This supposedly [citation or further research needed] takes a strain on the helix for after the sensory action has occurred, it then later on dies.
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