In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name organelle comes from the idea that these structures are parts of cells, as organs are to the body, hence organelle, the suffix -elle being a diminutive. Organelles are either separately enclosed within their own lipid bilayers (also called membrane-bounded organelles) or are spatially distinct functional units without a surrounding lipid bilayer (non-membrane bounded organelles). Although most organelles are functional units within cells, some function units that extend outside of cells are often termed organelles, such as cilia, the flagellum and archaellum, and the trichocyst (these could be referred to as membrane bound in the sense that they are attached to (or bound to) the membrane).
Organelles are identified by microscopy, and can also be purified by cell fractionation. There are many types of organelles, particularly in eukaryotic cells. They include structures that make up the endomembrane system (such as the nuclear envelope, endoplasmic reticulum, and Golgi apparatus), and other structures such as mitochondria and plastids. While prokaryotes do not possess eukaryotic organelles, some do contain protein-shelled bacterial microcompartments, which are thought to act as primitive prokaryotic organelles;[1] and there is also evidence of other membrane-bounded structures.[2] Also, the prokaryotic flagellum which protrudes outside the cell, and its motor, as well as the largely extracellular pilus, are often spoken of as organelles.
^Kerfeld CA, Sawaya MR, Tanaka S, Nguyen CV, Phillips M, Beeby M, Yeates TO (August 2005). "Protein structures forming the shell of primitive organelles". Science. 309 (5736): 936–8. Bibcode:2005Sci...309..936K. CiteSeerX 10.1.1.1026.896. doi:10.1126/science.1113397. PMID 16081736. S2CID 24561197.
^Cite error: The named reference Murat 2010 was invoked but never defined (see the help page).
In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name organelle comes from the idea that...
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A nitroplast is an organelle found in certain species of algae, particularly in the marine algae Braarudosphaera bigelowii. It plays a crucial role in...
heteroplasmy to occur, organelles must contain a genome and, in turn, a genotype. In animals, mitochondria are the only organelles that contain their own...
the plants, with chloroplasts. Eukaryotic cells contain membrane-bound organelles such as the nucleus, the endoplasmic reticulum, and the Golgi apparatus...
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A vacuole (/ˈvækjuːoʊl/) is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles...
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πλαστός (plastós) 'formed, molded'), pl. plastids, is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms...
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that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes...
also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the...
or outside the cell. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, the plasma membrane, or to the exterior...
membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Frequently...
or undulopodium (Greek: "swinging foot"; plural undulipodia), or a 9+2 organelle is a motile filamentous extracellular projection of eukaryotic cells....
of membrane-less organelles and organelle subdomains, which carry out specialized functions within the cell. Unlike many organelles, biomolecular condensate...
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single-cell organism whose cell lacks a nucleus and other membrane-bound organelles. The word prokaryote comes from the Ancient Greek πρό (pró) 'before' and...
components of the cytoplasm are the cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions...
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food vacuole, or digestive vacuole, is an organelle found in simple eukaryotes such as protists. This organelle is essentially a lysosome. During the stage...
proteins. The synapomorphies of genus Giardia include cells with duplicate organelles, absence of cytostomes, and ventral adhesive disc. About 40 species have...
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