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An organelle found in cnidoblast (nematoblast) cells. When matured, these stinging organelles store toxins and can deliver them when the cnidocil (a short extension of the cnidocyst) is stimulated by a prey or another stimulus. An actin-rich adhesion structure characterized by formation upon cell substrate contact and localization at the substrate-attached part of the cell, contain an F-actin-rich core surrounded by a ring structure containing proteins such as vinculin and talin, and have a diameter of 0.5 mm. A transient, cytoplasmic organelle found in Plasmodium species that resembles a cytoplasmic inclusion body and whose function is poorly understood. Crystalloids form in ookinetes and disappear after ookinete-to-oocyst transformation. Organized structure of distinctive morphology and function. Includes the nucleus, mitochondria, plastids, vacuoles, vesicles, ribosomes and the cytoskeleton, and prokaryotic structures such as anammoxosomes and pirellulosomes. Excludes the plasma membrane. A motor complex composed of an extracellular helical protein filament coupled to a rotary motor embedded in the cell envelope. Fibers, composed of actin, myosin, and associated proteins, found in cells of smooth or striated muscle. Organized structure of distinctive morphology and function, not bounded by a lipid bilayer membrane. Includes ribosomes, the cytoskeleton and chromosomes. Organized structure of distinctive morphology and function, occurring within the cell. Includes the nucleus, mitochondria, plastids, vacuoles, vesicles, ribosomes and the cytoskeleton. Excludes the plasma membrane. Any of the various filamentous elements that form the internal framework of cells, and typically remain after treatment of the cells with mild detergent to remove membrane constituents and soluble components of the cytoplasm. The term embraces intermediate filaments, microfilaments, microtubules, the microtrabecular lattice, and other structures characterized by a polymeric filamentous nature and long-range order within the cell. The various elements of the cytoskeleton not only serve in the maintenance of cellular shape but also have roles in other cellular functions, including cellular movement, cell division, endocytosis, and movement of organelles. A germline specific spherical organelle, rich in membrane skeletal proteins. Precursor to the fusome. A structure comprised of a core structure (in most organisms, a pair of centrioles) and peripheral material from which a microtubule-based structure, such as a spindle apparatus, is organized. Centrosomes occur close to the nucleus during interphase in many eukaryotic cells, though in animal cells it changes continually during the cell-division cycle. A cellular organelle, found close to the nucleus in many eukaryotic cells, consisting of a small cylinder with microtubular walls, 300-500 nm long and 150-250 nm in diameter. It contains nine short, parallel, peripheral microtubular fibrils, each fibril consisting of one complete microtubule fused to two incomplete microtubules. Cells usually have two centrioles, lying at right angles to each other. At division, each pair of centrioles generates another pair and the twin pairs form the pole of the mitotic spindle. A structure composed of a very long molecule of DNA and associated proteins (e.g. histones) that carries hereditary information. The array of microtubules and associated molecules that forms between opposite poles of a eukaryotic cell during mitosis or meiosis and serves to move the duplicated chromosomes apart. A small, dense body one or more of which are present in the nucleus of eukaryotic cells. It is rich in RNA and protein, is not bounded by a limiting membrane, and is not seen during mitosis. Its prime function is the transcription of the nucleolar DNA into 45S ribosomal-precursor RNA, the processing of this RNA into 5.8S, 18S, and 28S components of ribosomal RNA, and the association of these components with 5S RNA and proteins synthesized outside the nucleolus. This association results in the formation of ribonucleoprotein precursors; these pass into the cytoplasm and mature into the 40S and 60S subunits of the ribosome. An array of microtubules emanating from a spindle pole MTOC that do not connect to kinetochores. An actin-based, cross-linked cellular protrusion on the apical surface of auditory and vestibular hair cells. Stereocilium bundles act as mechanosensory organelles by responding to fluid motion or fluid pressure changes. A hollow structure made of protein, which usually has the form of a cylindrical tube closed by conical end caps. By regulating their relative gas vesicle content aquatic microbes are able to perform vertical migrations. Organized structure of distinctive morphology and function, not bounded by a lipid bilayer membrane and occurring within the cell. Includes ribosomes, the cytoskeleton and chromosomes. A large enclosure of aggregated pigment, typically bacteriochlorophyll c (BChl c), that acts as a light-harvesting antenna structure and is characteristic of green photosynthetic bacteria (e.g. Chlorobiaceae). The BChl aggregates are organized into lamellar elements by pigment-pigment rather than pigment-protein interactions. Chlorosomes also contain BChl a, carotenoids, quinones, lipids, and proteins, and are attached to the cytoplasmic membrane via a BChl a-containing protein baseplate. An intracellular organelle, about 200 A in diameter, consisting of RNA and protein. It is the site of protein biosynthesis resulting from translation of messenger RNA (mRNA). It consists of two subunits, one large and one small, each containing only protein and RNA. Both the ribosome and its subunits are characterized by their sedimentation coefficients, expressed in Svedberg units (symbol: S). Hence, the prokaryotic ribosome (70S) comprises a large (50S) subunit and a small (30S) subunit, while the eukaryotic ribosome (80S) comprises a large (60S) subunit and a small (40S) subunit. Two sites on the ribosomal large subunit are involved in translation, namely the aminoacyl site (A site) and peptidyl site (P site). Ribosomes from prokaryotes, eukaryotes, mitochondria, and chloroplasts have characteristically distinct ribosomal proteins. A multisubunit complex that is located at the centromeric region of DNA and provides an attachment point for the spindle microtubules. Any constituent part of the living contents of a cell; the matter contained within (but not including) the plasma membrane, usually taken to exclude large vacuoles and masses of secretory or ingested material. In eukaryotes it includes the nucleus and cytoplasm. A small cytoplasmic, non-membranous RNA/protein complex aggregates in the primordial germ cells of many higher eukaryotes. A prominent mass in the cytoplasm of previtellogenic oocytes. The cloud contains both mitochondria and electron-dense granulofibrillar material (GFM) and is the source of germinal granule material. An organelle found in bacteria consisting of a proteinaceous coat containing metabolic enzymes whose purpose is the sequestration or concentration of metabolites and which has the appearance of a polygonal granule by electron microscopy. A thylakoid that is derived from and attached to, but not necessarily continuous with, the plasma membrane, and is not enclosed in a plastid. It bears the photosynthetic pigments in photosynthetic cyanobacteria. The region of a bacterial cell, mitochondrion or chloroplast to which the DNA is confined.

View Gene Ontology (GO) Term


Name: intracellular non-membrane-bounded organelle
Acc: GO:0043232
Aspect: Cellular Component
Desc: Organized structure of distinctive morphology and function, not bounded by a lipid bilayer membrane and occurring within the cell. Includes ribosomes, the cytoskeleton and chromosomes.
  • intracellular non-membrane-enclosed organelle
Proteins in PDR annotated with:
   This term: 0
   Term or descendants: 11066 [Refine Search]


GO:0043232 - intracellular non-membrane-bounded organelle (interactive image map)

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