name: prospore membrane spindle pole body attachment site

description: The region of the prospore membrane to which the spindle pole body (SPB) is anchored; the prospore membrane extends from the SPB attachment site to surround the spore nucleus.


right middle basal body pair

category: biolink:CellularComponent biolink:AnatomicalEntity biolink:PhysicalEssence biolink:OrganismalEntity biolink:SubjectOfInvestigation biolink:BiologicalEntity biolink:ThingWithTaxon biolink:NamedThing biolink:PhysicalEssenceOrOccurrent

description: Set of two basal bodies found in Giardia species (trophozoite stage). It comprises the caudal and posteriolateral basal bodies located to the left of the right nucleus of the trophozoite when viewed dorsally.


name: medial layer of collagen and cuticulin-based cuticle extracellular matrix

description: The fluid-filled cuticle layer that lies between the cortical and basal layers and is characterized by the presence of regularly spaced columnar struts that lie on either side of the annular furrows and link the two surrounding layers. In C. elegans, a defined medial layer is found only in adult animals.


cell septum

description: A structure composed of peptidoglycan and often chitin in addition to other materials. It usually forms perpendicular to the long axis of a cell or hypha and grows centripetally from the cell wall to the center of the cell and often functions in the compartmentalization of a cell into two daughter cells.


late endosome lumen

description: The volume enclosed by the membrane of a late endosome.


apical pole of neuron

description: Portion of a neuron cell soma closest to the point where the apical dendrite emerges.


cytoskeletal calyx

description: A large cytoskeletal structure located at the posterior end of the perinuclear theca of a mammalian sperm head. The nucleus is tightly associated with the calyx, which contains calicin and basic cylicin proteins.


host cell presynaptic membrane

description: A specialized area of membrane of the host axon terminal that faces the plasma membrane of the host neuron or muscle fiber with which the axon terminal establishes a synaptic junction; many host synaptic junctions exhibit structural presynaptic characteristics, such as conical, electron-dense internal protrusions, that distinguish it from the remainder of the axon plasma membrane.


somatic ring canal

description: A stable intercellular bridge between somatic cells. Examples include the intercellular bridges between ovarian follicle cells in insects and between imaginal disc cells in insects.


type III terminal bouton

description: Terminal inflated portion of the axon of a non-glutamatergic neuron, containing the specialized apparatus necessary to release neurotransmitters at a regulatory synapse. The axon terminus is considered to be the whole region of thickening and the terminal bouton is a specialized region of it. Type III terminal boutons are larger than type II ones.


bacterial extracellular vesicle

description: Small membrane vesicle (< 1 um) that buds off a prokaryotic cell plasma membrane, able to carry proteins, phospholipids, lipopolysaccharides, nucleic acids, viruses, and more. Important in intercellular communication and pathogenesis; can exist within host cells.


dinoflagellate antapical horn

description: A horn-shaped dinoflagellate antapex found in thecate species.


name: epicuticle of collagen and cuticulin-based cuticle extracellular matrix

description: A lipid-containing layer of cuticle that lies between the cortical layer and the surface coat. An example of this component is found in Caenorhabditis elegans.


muscle cell postsynaptic specialization

description: A postsynaptic specialization that is part of a neuromuscular junction.


right lateral basal body pair

description: Set of two basal bodies found in Giardia species (trophozoite stage). It comprises the anterior and ventral basal bodies located to the left of the right nucleus of the trophozoite when viewed dorsally.


sperm individualization complex

description: A cellular structure that includes cytoskeletal components and part of the cell membrane. Forms at the nuclear end of a male germline syncytium, or cyst, and translocates the over the length of the syncytium in the course of sperm individualization. Each complex contains an array of 64 investment cones, one per nucleus, that move synchronously along the spermatogenic cyst.


chloroplast thylakoid lumen

description: The cavity enclosed within the chloroplast thylakoid membrane. An example of this component is found in Arabidopsis thaliana.


meiotic spindle midzone

description: The area in the center of the meiotic spindle where the spindle microtubules from opposite poles overlap.


cell envelope

description: An envelope that surrounds a bacterial cell and includes the cytoplasmic membrane and everything external, encompassing the periplasmic space, cell wall, and outer membrane if present.


curli

description: A proteinaceous extracellular fiber, produced by an enteric bacterium, that is involved in surface and cell-cell contacts that promote community behavior and host colonization.


actin rod

description: A cellular structure consisting of parallel, hexagonally arranged actin tubules, comprising filamentous actin and associated proteins. Actin rod structures are found in diverse organisms, having been observed in spores of Dictyostelium discoideum, Drosophila melanogaster oocytes, as well as in numerous animal cells under stress conditions.


name: nucleoplasmic periphery of the nuclear pore complex

description: Nucleoplasm situated in close proximity and peripheral to a nuclear pore complex.


plastid inner membrane

description: The inner, i.e. lumen-facing, lipid bilayer of the plastid envelope; also faces the plastid stroma.


intracellular canaliculus

description: An apical plasma membrane part that forms a narrow enfolded luminal membrane channel, lined with numerous microvilli, that appears to extend into the cytoplasm of the cell. A specialized network of intracellular canaliculi is a characteristic feature of parietal cells of the gastric mucosa in vertebrates.


name: cellularization cleavage furrow invagination front

description: The base of the cellularization invagination or cleavage furrow most distal to the original multi-nucleate cell or syncytium plasma membrane.


dendritic shaft

description: Cylindric portion of the dendrite, directly stemming from the perikaryon, and carrying the dendritic spines.


photoreceptor disc membrane

description: Stack of disc membranes located inside a photoreceptor outer segment, and containing densely packed molecules of photoreceptor proteins that traverse the lipid bilayer. Disc membranes arise as evaginations of the ciliary membrane during the development of the outer segment and may or may not remain contiguous with the ciliary membrane.


perinuclear endoplasmic reticulum

description: The portion of endoplasmic reticulum, the intracellular network of tubules and cisternae, that occurs near the nucleus. The lumen of the perinuclear endoplasmic reticulum is contiguous with the nuclear envelope lumen (also called perinuclear space), the region between the inner and outer nuclear membranes.


suberin network

description: An extracellular matrix part that consists of fatty acid-derived polymers, including both aromatic and aliphatic components. The suberin network is found in specialized plant cell walls, where it is laid down between the primary wall and plasma membrane, forms protective and wound-healing layers, and provides a water-impermeable diffusion barrier.


elaioplast stroma

description: The space enclosed by the double membrane of an elaioplast.


plant-type vacuole membrane

description: The lipid bilayer surrounding a vacuole that retains the same shape regardless of cell cycle phase. The membrane separates its contents from the cytoplasm of the cell. An example of this component is found in Arabidopsis thaliana.


prospore contractile ring

description: A contractile ring, i.e. a cytoskeletal structure composed of actin filaments and myosin, that forms beneath the plasma membrane of the prospore envelope in meiotic cells in preparation for completing cytokinesis.


myelin sheath abaxonal region

description: The region of the myelin sheath furthest from the axon.


mesosome

description: An intracellular, often complex, membranous structure, sometimes with additional membranous lamellae inside, found in bacteria. They are associated with synthesis of DNA and secretion of proteins.


germ cell nucleus

description: The nucleus of a germ cell, a reproductive cell in multicellular organisms.


filopodium membrane

description: The portion of the plasma membrane surrounding a filopodium.


septin band

description: A diffuse ring composed of a series of septin bars that run parallel to the long axis of the cell. This type of septin structure has been observed in a number of locations associated with polarized grown and/or deposition of new membrane, but not with cytokinesis, such as at the shmoo (mating projection) neck, at the junction between the mother cell and the germ tube (hypha) of a fungal cell growing filamentously.


name: bacterial-type flagellum basal body, C ring

description: Cytoplasmic ring located at the base of the bacterial-type flagellar basal body; acts as a rotor; includes three switch proteins, which generate torque and can change their conformational state in a bimodal fashion, so that the motor direction can switch between clockwise and counterclockwise.


name: extrinsic component of thylakoid membrane

description: The component of a thylakoid membrane consisting of gene products and protein complexes that are loosely bound to one of its surfaces, but not integrated into the hydrophobic region.


cyst wall

description: The specialized envelope lying outside the cell membrane of a cyst. A cyst is a resting or dormant stage of a microorganism, usually a bacterium or a protist or rarely an invertebrate animal, that helps the organism to survive in unfavorable environmental conditions. In protists such as protozoan parasites alternating cystic- and non-cystic stages, the cyst wall is usually composed of carbohydrates and proteins.


stereocilium membrane

description: The portion of the plasma membrane surrounding a stereocilium.


inner membrane pellicle complex

description: A membrane structure formed of two closely aligned lipid bilayers that lie beneath the plasma membrane and form part of the pellicle surrounding an apicomplexan parasite cell.


orthogonal array

description: Square array of closely spaced intramembrane particles, 4-6 nm in size, that form supramolecular aggregates found in the plasma membrane of astrocytes, skeletal muscle and epithelial cells. They have been shown to contain aquaporins (water channels).


endospore cortex

description: A layer surrounding a bacterial endospore found inside the outer endospore membrane, but outside the membrane surrounding the endospore core. It consists of peptidoglycan of a different chemical nature than that found in vegetative cell walls which results in less cross-linking of peptidoglycan.


name: half bridge of mitotic spindle pole body

description: Structure adjacent to the plaques of the mitotic spindle pole body.


post-anaphase microtubule array

description: A cytoskeletal part that consists of an array of microtubules and associated molecules that forms at the end of anaphase, and in which microtubules are nucleated from an equatorial microtubule organizing center.


node of Ranvier

description: An axon part that is a gap in the myelin where voltage-gated sodium channels cluster and saltatory conduction is executed.


host cell periplasmic space

description: The region between the inner (cytoplasmic) and outer host membrane (Gram-negative Bacteria) or inner host membrane and host cell wall (Fungi).


gas vesicle shell

description: The proteinaceous structure surrounding a gas vesicle.


root hair tip

description: The tip portion of an outgrowth of a root epidermal cell.


anammoxosome

description: An intracytoplasmic membrane-bounded compartment in anaerobic ammonium oxidation (anammox) bacteria, is the site of anammox catabolism.


P4 peroxisome

description: A subform of peroxisome that corresponds to an intermediate in a peroxisome assembly pathway, which operates by conversion of peroxisomal subforms in the direction P1, P2 -> P3 -> P4 -> P5 -> P6. P4 peroxisomes are distinguished from the other subforms on the bases of buoyant density and protein content.


name: outer plaque of mitotic spindle pole body

description: One of three laminate structures that form the mitotic spindle pole body; the outer plaque is in the cytoplasm.


extracellular organelle

description: Organized structure of distinctive morphology and function, occurring outside the cell. Includes, for example, extracellular membrane vesicles (EMVs) and the cellulosomes of anaerobic bacteria and fungi.


host caveola

description: A small pit, depression, or invagination, such as any of the minute pits or incuppings of the host cell membrane formed during pinocytosis, that communicates with the outside of a host cell and extends inward, indenting the host cytoplasm and the host cell membrane. Such caveolae may be pinched off to form free vesicles within the host cytoplasm. The host is defined as the larger of the organisms involved in a symbiotic interaction.


unicellular trichome apex

description: A cell projection part that is the apical most portion of a unicellular trichome.


lateral shield

description: Region of the ventral side of the cell body found in Giardia species (trophozoite stage). It is located posterior on either side of the ventral groove; the upper boundary is the ventral disc, and the lower boundary is marked by the posteriolateral flagella.


plasma membrane-derived chromatophore

description: A pigment-bearing structure that is derived from the cytoplasmic membrane, sometimes consisting of simple invaginations and sometimes a complete vesicle. This component is found in certain photosynthetic bacteria and cyanobacteria.


ascus membrane

description: A double layer of lipid molecules that surrounds an ascus, a capsule containing the sexual spores in some fungi.


brush border membrane

description: The portion of the plasma membrane surrounding the brush border.


spine apparatus membrane

description: The lipid bilayer surrounding the spine apparatus.


old growing cell tip

description: A cell tip which has existed for at least one complete cell cycle, and at which polarized growth occurs. For example, in fission yeast the cell end that existed prior to cell division grows immediately after division, and contains a distinctive complement of proteins including actin cytoskeletal structures.


ciliary tip

description: Part of the cilium where the axoneme ends. The ciliary tip has been implicated in ciliary assembly and disassembly, as well as signal transduction.


intine

description: The innermost of the major layers of the pollen grain wall which underlies the exine and borders the cytoplasm.


cellular bud neck

description: The constriction between the mother cell and daughter cell (bud) in an organism that reproduces by budding.


microsporidian-type exospore

description: The dense, protein rich outermost layer of a microsporidian spore wall that lies above the endospore.


sarcoplasmic reticulum lumen

description: The volume enclosed by the membranes of the sarcoplasmic reticulum.


rDNA protrusion

description: Any of the tandem arrays of rDNA localized at the periphery of the nucleus and protruding into the nucleolus, and associated proteins. May be visible as a single or double spot by DAPI staining.


microneme lumen

description: The volume enclosed by the microneme membrane.


Casparian strip

description: Region of plant cell wall specialised to act as a seal to prevent back leakage of secreted material (analogous to tight junction between epithelial cells). Found particularly where root parenchymal cells secrete solutes into xylem vessels. The barrier is composed of suberin; a fatty substance, containing long chain fatty acids and fatty esters, also found in the cell walls of cork cells (phellem) in higher plants.


rhoptry neck

description: Narrow, electron-dense part of the rhoptry that extends through the conoid at the apical tip of an apicomplexan parasite. The rhoptry neck serves as a duct through which the contents of the rhoptry are secreted after attachment to the host has been completed and at the commencement of invasion.


GABA-ergic synapse

description: A synapse that uses GABA as a neurotransmitter. These synapses are typically inhibitory.


podosome core

description: The F-actin-rich core of an adhesion structure characterized by formation upon cell substrate contact and localization at the substrate-attached part of the cell.


exine

description: The outer layer of the pollen grain wall which is composed primarily of sporopollenin.


inhibitory synapse

description: A synapse in which an action potential in the presynaptic cell reduces the probability of an action potential occurring in the postsynaptic cell.


amphisome

description: Intermediate organelles formed during macroautophagy through the fusion between autophagosomes and endosomes.


magnetosome membrane

description: The lipid bilayer surrounding a magnetosome.


phagophore

description: A disk-like structure that expands, rounds up into a cup-shaped structure, and eventually closes around its cargo (for example cytoplasmic components) to become an autophagosome or Cvt vesicle.


conoid

description: A spiral cytoskeletal structure located at the apical end of the apical complex in some apicomplexan parasites. Fibers form a left-handed spiral, and are comprised of tubulin protofilaments organized in a ribbon-like structure that differs from the conventional tubular structure characteristic of microtubules.


polar ring of apical complex

description: An electron dense ring at the most anterior position of the apical complex, from which the conoid fibers originate; formed during an invasive life cycle stage of an apicomplexan parasite.


hydrogenosomal membrane

description: The lipid bilayer surrounding a hydrogenosome.


cleavage furrow leading edge

description: The 'trough' of the cleavage furrow. This is the part of the cleavage furrow closest to the contractile ring.


external side of fungal-type cell wall

description: The side of the fungal-type cell wall that is opposite to the side that faces the cell and its contents.


growing cell tip

description: The region at either end of the longest axis of a cylindrical or elongated cell, where polarized growth occurs.


name: axonemal microtubule doublet inner junction

description: The structure which joins the B10 protofilament of the B tubule to the A1 protofilament of the A tubule within an axonemal microtubule doublet.


mitosome

description: A double-membrane-bounded organelle that functions in iron-sulfur protein maturation; evolutionarily derived from mitochondria. The mitosome has been detected only in anaerobic or microaerophilic organisms that do not have mitochondria, such as Entamoeba histolytica, Giardia intestinalis and several species of Microsporidia. These organisms are not capable of gaining energy from oxidative phosphorylation, which is normally performed by mitochondria.


bilobe structure

description: A cytoskeletal structure in some kinetoplastid species linking the structures of the ciliary pocket collar and the flagellum attachment zone (aka cilium attachment zone).


actin filament branch point

description: The part of an actin filament where the structure forks.


hydrogenosome

description: A spherical, membrane-bounded organelle found in some anaerobic protozoa, which participates in ATP and molecular hydrogen formation.


symbiont-containing vacuolar space

description: The space between a symbiont plasma membrane and the symbiont-containing vacuole membrane.


endonuclear canal

description: A membrane-bound structure present in the nucleus of a spermatozoon. There is variation in the number of endonuclear canals between sperm of different organisms, and some species lack these structures altogether. The endonuclear canal may provide a supporting role for the sperm nucleus, and originates during spermiogenesis from an invagination of the nuclear envelope.


endothelial microparticle

description: A blood microparticle that is derived from, and contains membrane receptors as well as other proteins characteristic of, an endothelial cell.


name: presynaptic active zone dense projection

description: Electron dense projection extending from the cytomatrix into the cytoplasm on which synaptic vesicles are tethered.


acrosomal matrix

description: A structural framework, or 'dense core' at the interior of an acrosome. May regulate the distribution of hydrolases within the acrosome and their release during the acrosome reaction.


etioplast prolamellar body

description: A three dimensional regular lattice found in etioplasts. It is composed of a continuous system of tubules but when exposed to light the symmetrical arrangement is rapidly lost as tubules become pinched off into two dimensional sections of lattice. These for perforated sheets of membrane that move apart, extend and increase, finally establishing the typical granal and intergranal lamellae of the mature chloroplast.


Hechtian strand

description: An extended membranous thread which firmly connects the plasma membrane to the cell wall during plasmolysis such that the plasma membrane does not separate from the cell wall completely.


platelet dense tubular network lumen

description: The volume enclosed by the membranes of the platelet dense tubular network.


Golgi lumen

description: The volume enclosed by the membranes of any cisterna or subcompartment of the Golgi apparatus, including the cis- and trans-Golgi networks.


cytostome

description: Stable, specialized structure for the ingestion of food by the cell into phagosomes.


endosperm protein body

description: A membrane-bounded plant organelle found in the developing endosperm, contains storage proteins.


name: bacterial-type flagellum basal body, distal rod, P ring

description: One of the rings of the bacterial-type flagellar basal body; anchors the basal body to the peptidoglycan layer.


transverse filament

description: A structural unit of the synaptonemal complex that spans the regions between the lateral elements and connects them.


prominosome

description: An extracellular membrane-bounded vesicle that contains prominin proteins (in mouse Prom1/CD33 or Prom2) and are found in body fluids including ventricular fluid, saliva, urine and seminal fluid. In the ventricular fluid of the developing mouse brain two major classes of these particles have been observed (P2 particles of 500-1000 nm and P4 particles of 50-80 nm) which likely originate from microvilli, primary cilia and/or the midbody of neuroepithelial cells. The physiological role is not known.


name: extrinsic component of external side of cell outer membrane

description: The component of a cell outer membrane consisting of gene products and protein complexes that are loosely bound to its external surface, but not integrated into the hydrophobic region.


bacterial biofilm matrix surface

description: The external part of the biofilm matrix, a structure lying external to bacterial cells. A biofilm is an aggregate of surface-associated bacteria, and the biofilm matrix is the envelope of polymeric substances that surrounds the bacteria.


extrachromosomal circular DNA

description: Circular DNA structures that are not part of a chromosome.


adventitious septum

description: A cell septum whose formation is independent of nuclear division.


sperm annulus

description: The ring-like, filamentous structure located at the distal end of the midpiece of the sperm flagellum; the annulus is thought to form a diffusion barrier between the midpiece and the principal piece and serve as a stabilizing structure for tail rigidity.


neural crest-derived structure

category: biolink:AnatomicalEntity biolink:PhysicalEssence biolink:OrganismalEntity biolink:SubjectOfInvestigation biolink:BiologicalEntity biolink:ThingWithTaxon biolink:NamedThing biolink:PhysicalEssenceOrOccurrent

description: An anatomical structure that develops from the neural crest.


ectoderm-derived structure

description: An anatomical structure that develops (entirely or partially) from the ectoderm.


name: structure with developmental contribution from neural crest

description: An anatomical structure that has some part that develops from the neural crest.


mesoderm-derived structure

description: An anatomical structure that develops (entirely or partially) from the mesoderm.


description: A location, relative to cellular compartments and structures, occupied by a macromolecular machine. There are three types of cellular components described in the gene ontology: (1) the cellular anatomical entity where a gene product carries out a molecular function (e.g., plasma membrane, cytoskeleton) or membrane-enclosed compartments (e.g., mitochondrion); (2) virion components, where viral proteins act, and (3) the stable macromolecular complexes of which gene product are parts (e.g., the clathrin complex).