A microtubule-based process that results in the movement of organelles, other microtubules, or other cellular components. Examples include motor-driven movement along microtubules and movement driven by polymerization or depolymerization of microtubules.

Any process that activates or increases the frequency, rate or extent of cold-induced thermogenesis.

The directed movement of the nucleus to a specific location within a cell.

The mitotic cell cycle transition by which a cell in G2 commits to M phase. The process begins when the kinase activity of M cyclin/CDK complex reaches a threshold high enough for the cell cycle to proceed. This is accomplished by activating a positive feedback loop that results in the accumulation of unphosphorylated and active M cyclin/CDK complex.

The formation of a spore-bearing structure by fungus where spores will arise from asexual reproduction.

The directed movement of substances from the endoplasmic reticulum (ER) to the Golgi, mediated by COP II vesicles. Small COP II coated vesicles form from the ER and then fuse directly with the cis-Golgi. Larger structures are transported along microtubules to the cis-Golgi.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of a vacuole.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The process in which genetic material, in the form of chromosomes, is organized into specific structures and then physically separated and apportioned to two or more sets. In eukaryotes, chromosome segregation begins with the condensation of chromosomes, includes chromosome separation, and ends when chromosomes have completed movement to the spindle poles.

Any signalling pathway that modulates the activity of a cell cycle cyclin-dependent protein kinase to modulate the switch from G2 phase to M phase of the mitotic cell cycle.

The process in which an antigen-presenting cell expresses a peptide antigen of exogenous origin on its cell surface in association with an MHC class II protein complex. The peptide antigen is typically, but not always, processed from a whole protein.

Any process that activates or increases the frequency, rate or extent of the directed movement of substances within cells.

The aggregation, arrangement and bonding together of proteins and RNA molecules to form a cytoplasmic mRNA processing body.

The aggregation, arrangement and bonding together of proteins and RNA molecules to form a stress granule.

The regulated exocytosis of secretory granules containing preformed mediators such as proteases, lipases, and inflammatory mediators by a neutrophil.

The directed movement of the spindle to a specific location in the cell.

Any process in which the nucleus is transported to, and/or maintained in, a specific location within the cell.

Any process that modulates the rate, frequency or extent of the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The directed movement of a vesicle towards the minus end of a microtubule, mediated by motor proteins. This process begins with the attachment of a vesicle to a microtubule, and ends when the vesicle reaches its final destination.

Any process that modulates the rate, frequency, or extent of metaphase plate congression, the alignment of chromosomes at the metaphase plate, a plane halfway between the poles of the spindle.

The docking of a cytosolic centriole/basal body to the plasma membrane via the ciliary transition fibers. In some species this may happen via an intermediate step, by first docking to the ciliary vesicle via the ciliary transition fibers. The basal body-ciliary vesicle then relocates to the plasma membrane, followed by the ciliary vesicle fusing with the plasma membrane, effectively attaching the basal body to the plasma membrane.

Any process that activates or increases the frequency, rate or extent of spindle assembly.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The process in which genetic material, in the form of chromosomes, is organized into specific structures and then physically separated and apportioned to two or more sets. In eukaryotes, chromosome segregation begins with the condensation of chromosomes, includes chromosome separation, and ends when chromosomes have completed movement to the spindle poles.

The process in which neuronal axons and dendrites become coated with a segmented lipid-rich sheath (myelin) to enable faster and more energetically efficient conduction of electrical impulses. The sheath is formed by the cell membranes of oligodendrocytes in the central nervous system. Adjacent myelin segments are separated by a non-myelinated stretch of axon called a node of Ranvier.

Any process that activates or increases the frequency, rate or extent of the directed movement of substances within cells.

The aggregation, arrangement and bonding together of proteins and RNA molecules to form a stress granule.

The process in which myelin sheaths are formed and maintained around neurons. Oligodendrocytes in the brain and spinal cord and Schwann cells in the peripheral nervous system wrap axons with compact layers of their plasma membrane. Adjacent myelin segments are separated by a non-myelinated stretch of axon called a node of Ranvier.

The process in which a relatively unspecialized cell acquires the specialized features of a photoreceptor cell in a camera-type eye.

Any process that modulates the rate, frequency or extent of the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The directed movement of a vesicle towards the minus end of a microtubule, mediated by motor proteins. This process begins with the attachment of a vesicle to a microtubule, and ends when the vesicle reaches its final destination.

Any process that modulates the rate, frequency, or extent of metaphase plate congression, the alignment of chromosomes at the metaphase plate, a plane halfway between the poles of the spindle.

Any process that activates or increases the frequency, rate or extent of spindle assembly.

A cell cycle process that sets the alignment of mitotic spindle relative to other cellular structures.

Progression through the phases of the mitotic cell cycle, the most common eukaryotic cell cycle, which canonically comprises four successive phases called G1, S, G2, and M and includes replication of the genome and the subsequent segregation of chromosomes into daughter cells. In some variant cell cycles nuclear replication or nuclear division may not be followed by cell division, or G1 and G2 phases may be absent.

The process of physically separating the septal cell wall material by enzymatic digestion, that occurs after daughter cells are separated by cytokinesis.

The directed, self-propelled movement of a cilium.

The directed movement of proteins in a cell, including the movement of proteins between specific compartments or structures within a cell, such as organelles of a eukaryotic cell.

A microtubule-based process that results in the movement of organelles, other microtubules, or other cellular components. Examples include motor-driven movement along microtubules and movement driven by polymerization or depolymerization of microtubules.

A microtubule-based process that results in the movement of organelles, other microtubules, or other cellular components. Examples include motor-driven movement along microtubules and movement driven by polymerization or depolymerization of microtubules.

A microtubule-based process that results in the movement of organelles, other microtubules, or other cellular components. Examples include motor-driven movement along microtubules and movement driven by polymerization or depolymerization of microtubules.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the spindle, the array of microtubules and associated molecules that forms between opposite poles of a eukaryotic cell during DNA segregation and serves to move the duplicated chromosomes apart.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The cell cycle process in which centrosome duplication and separation takes place. The centrosome cycle can operate with a considerable degree of independence from other processes of the cell cycle.

Formation of a small group of cells (pole cells) at the posterior pole of the insect blastula. They are the first cells to cellularize after the arrival of nuclei at the end of the syncytial blastula stage and are the precursors to the insect germ cells.

Any of the rounds of incomplete mitosis undergone by a cystoblast to form a cyst of interconnected cells.

The process whose specific outcome is the progression of a spermatid over time, from its formation to the mature structure.

The cell fate determination process in which a germarium-derived cell becomes capable of differentiating autonomously into an oocyte cell regardless of its environment; upon determination, the cell fate cannot be reversed. An example of this is found in Drosophila melanogaster.

The directed movement of a border cell through the nurse cells to reach the oocyte. An example of this is found in Drosophila melanogaster.

The directed movement of the oocyte nucleus within the cell as part of the establishment and maintenance of the dorsal/ventral axis of the oocyte. An example of this is found in Drosophila melanogaster.

The separation of a multi-nucleate cell or syncytium into individual cells. An example of this is found in Drosophila melanogaster embryo development.

The expansion of a neuroblast population by cell division. A neuroblast is any cell that will divide and give rise to a neuron.

The series of events required for an organism to receive an auditory stimulus, convert it to a molecular signal, and recognize and characterize the signal. Sonic stimuli are detected in the form of vibrations and are processed to form a sound.

The behavior of an adult relating to the progression of that organism along the ground by the process of lifting and setting down each leg.

Behavior that is dependent upon the sensation of chemicals.

The behavior of a male, for the purpose of attracting a sexual partner. An example of this process is found in Drosophila melanogaster.

The directed movement of organelles or molecules along microtubules in neuron projections.

The directed movement of organelles or molecules along microtubules from the cell periphery toward the cell body in nerve cell axons.

Any process in which a protein is transported to, or maintained in, a specific location.

Any process in which mRNA is transported to, or maintained in, a specific location within the cell.

Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of deprivation of nourishment.

The process whose specific outcome is the progression of the mushroom body over time, from its formation to the mature structure. The mushroom body is composed of the prominent neuropil structures of the insect central brain, thought to be crucial for olfactory associated learning. These consist mainly of a bulbous calyx and tightly packaged arrays of thin parallel fibers of the Kenyon cells.

Any process that modulates the frequency, rate or extent of the cell cycle process in which a cell progresses from metaphase to anaphase during mitosis, triggered by the activation of the anaphase promoting complex by Cdc20/Sleepy homolog which results in the degradation of Securin.

The process in which a multicellular organism, a unicellular organism or a group of unicellular organisms grow in a threadlike, filamentous shape.

Any process that stops, prevents, or reduces the frequency, rate or extent of any TGF-beta receptor signaling pathway.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the fusome of ovarian cells, an organelle derived from the spectrosome. It anchors the mitotic spindle pole to provide orientation during cystoblast cell divisions.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of structures formed of microtubules and associated proteins in the cytoplasm of a cell.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of structures formed of microtubules and associated proteins in the cytoplasm of a cell.

The behavior of an organism in response to a sound.

Any process that activates or increases the frequency, rate or extent of the directed movement of substances within cells.

The aggregation, arrangement and bonding together of proteins and RNA molecules to form a cytoplasmic mRNA processing body.

Any process in which a protein is transported to, or maintained at, the kinetochore.

Formation of a multilayered, melanized sheath of cells around a foreign invader.

Creation of the central hole of a tube in an open tracheal system through which gases flow.

The directed movement of large protein complexes along microtubules from the tip of a cilium (also called flagellum) toward the cell body, mediated by motor proteins.

The process in which a group of unicellular organisms grow in a threadlike, filamentous shape in response to deprivation of nourishment.

The process in which a group of unicellular organisms grow in a threadlike, filamentous shape in response to a biotic (living) stimulus.

The cell cycle process in which the directed movement of the mitotic spindle to a specific location in the cell occurs.

The cell cycle process in which the directed movement of the mitotic spindle to a specific location in the cell occurs.

Synthesis and deposition of a chitin-based noncellular, hardened, or membranous secretion from an epithelial sheet. An example of this process is found in Drosophila melanogaster.

Entry into the facultative diapause of the dauer (enduring) larval stage of nematode development.

Any cellular process that results in the specification, formation or maintenance of the apicobasal polarity of an epithelial cell.

The specification and formation of the apicobasal polarity of an epithelial cell.

The process during wing vibration where the male insect produces a species-specific acoustic signal called a love song.

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the fusome, a large intracellular spectrin-rich structure found in insect germline cells and mammalian hematopoietic cells.

Any process that activates or increases the frequency, rate or extent of centrosome separation.

The directed movement of a vesicle along a microtubule, mediated by motor proteins. This process begins with the attachment of a vesicle to a microtubule, and ends when the vesicle reaches its final destination.

Formation of a group of interconnected cells derived from a single gonial founder cell.

Any process that establishes the spatial arrangement of mitochondria between and within cells.

The complete process of formation and maturation of an ovum or female gamete from a primordial female germ cell. Examples of this process are found in Mus musculus and Drosophila melanogaster.

The process in which the anatomical structures of a dendrite are generated and organized.

The directed movement of RNA, ribonucleic acids, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore.

Any process in which RNA is maintained in a location and prevented from moving elsewhere.

The directed movement of the spindle to a specific location in the cell.

Any process in which a centrosome is transported to, and/or maintained in, a specific location within the cell.

The directed movement of the Golgi to a specific location.

Any process that modulates the rate, frequency or extent of the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle.

The assembly of a cilium, a specialized eukaryotic organelle that consists of a filiform extrusion of the cell surface. Each cilium is bounded by an extrusion of the cytoplasmic membrane, and contains a regular longitudinal array of microtubules, anchored basally in a centriole.

Any process that increases the rate, frequency, or extent of dauer larval development, the process whose specific outcome is the progression of the dauer larva over time, through the facultative diapause of the dauer (enduring) larval stage, with specialized traits adapted for dispersal and long-term survival, with elevated stress resistance and without feeding.

The process whose specific outcome is the progression of metulae over time, from its formation to the mature structure. Metulae are elongated mononucleate cells that bud from the surface of the conidiophore tip.

The directed movement of a vesicle towards the minus end of a microtubule, mediated by motor proteins. This process begins with the attachment of a vesicle to a microtubule, and ends when the vesicle reaches its final destination.

Any process that modulates the rate, frequency, or extent of metaphase plate congression, the alignment of chromosomes at the metaphase plate, a plane halfway between the poles of the spindle.

The aggregation, arrangement and bonding together of a set of components to form the spindle that contributes to the process of mitosis.

The aggregation, arrangement and bonding together of a set of components to form the spindle that contributes to the process of mitosis.

A process that is carried out at the cellular level which results in the arrangement of constituent parts of a phagosome within a cell. Phagosome maturation begins with endocytosis and formation of the early phagosome and ends with the formation of the hybrid organelle, the phagolysosome.

The directed movement of mitochondria along microtubules in axons towards the cell body and away from the presynapse.

Any process that activates or increases the frequency, rate or extent of cold-induced thermogenesis.

Any process that activates or increases the frequency, rate or extent of neuron remodeling.

Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a 3,3',5-triiodo-L-thyronine stimulus.

The aggregation, arrangement and bonding together of a set of components to form a non-motile cilium.

Any process that activates or increases the frequency, rate or extent of spindle assembly.

A process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a nerve growth factor stimulus.

Any multimeric complex connected to a microtubule.

Any dynein complex with a homodimeric dynein heavy chain core that catalyzes movement along a microtubule. Cytoplasmic dynein complexes participate in many cytoplasmic transport activities in eukaryotes, such as mRNA localization, intermediate filament transport, nuclear envelope breakdown, apoptosis, transport of centrosomal proteins, mitotic spindle assembly, virus transport, kinetochore functions, and movement of signaling and spindle checkpoint proteins. Some complexes participate in intraflagellar transport. Subunits associated with the dynein heavy chain mediate association between dynein heavy chain and cargoes, and may include light chains and light intermediate chains.

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.

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.

The space external to the outermost structure of a cell. For cells without external protective or external encapsulating structures this refers to space outside of the plasma membrane. This term covers the host cell environment outside an intracellular parasite.

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

Any dynein complex with a homodimeric dynein heavy chain core that catalyzes movement along a microtubule. Cytoplasmic dynein complexes participate in many cytoplasmic transport activities in eukaryotes, such as mRNA localization, intermediate filament transport, nuclear envelope breakdown, apoptosis, transport of centrosomal proteins, mitotic spindle assembly, virus transport, kinetochore functions, and movement of signaling and spindle checkpoint proteins. Some complexes participate in intraflagellar transport. Subunits associated with the dynein heavy chain mediate association between dynein heavy chain and cargoes, and may include light chains and light intermediate chains.

Any dynein complex with a homodimeric dynein heavy chain core that catalyzes movement along a microtubule. Cytoplasmic dynein complexes participate in many cytoplasmic transport activities in eukaryotes, such as mRNA localization, intermediate filament transport, nuclear envelope breakdown, apoptosis, transport of centrosomal proteins, mitotic spindle assembly, virus transport, kinetochore functions, and movement of signaling and spindle checkpoint proteins. Some complexes participate in intraflagellar transport. Subunits associated with the dynein heavy chain mediate association between dynein heavy chain and cargoes, and may include light chains and light intermediate chains.

Any of the long, generally straight, hollow tubes of internal diameter 12-15 nm and external diameter 24 nm found in a wide variety of eukaryotic cells; each consists (usually) of 13 protofilaments of polymeric tubulin, staggered in such a manner that the tubulin monomers are arranged in a helical pattern on the microtubular surface, and with the alpha/beta axes of the tubulin subunits parallel to the long axis of the tubule; exist in equilibrium with pool of tubulin monomers and can be rapidly assembled or disassembled in response to physiological stimuli; concerned with force generation, e.g. in the spindle.

A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.

The volume enclosed by the membrane of an azurophil granule, a primary lysosomal granule found in neutrophil granulocytes that contains a wide range of hydrolytic enzymes and is released into the extracellular fluid.

A vesicle that is released into the extracellular region by fusion of the limiting endosomal membrane of a multivesicular body with the plasma membrane. Extracellular exosomes, also simply called exosomes, have a diameter of about 40-100 nm.

The region of a cell that lies just beneath the plasma membrane and often, but not always, contains a network of actin filaments and associated proteins.

Any of several large complexes that contain two or three dynein heavy chains and several light chains, and have microtubule motor activity.

A multisubunit complex that is located at the centromeric region of DNA and provides an attachment point for the spindle microtubules.

The end, or tip, of a fungal hypha, where polarized growth occurs during hyphal elongation.

A tubular array of microtubules that extends from the perinuclear ring surrounding the spermatid nucleus to the flagellar axoneme. The manchette may also contain F-actin filaments.

A tubular array of microtubules that extends from the perinuclear ring surrounding the spermatid nucleus to the flagellar axoneme. The manchette may also contain F-actin filaments.

The double lipid bilayer enclosing the nucleus and separating its contents from the rest of the cytoplasm; includes the intermembrane space, a gap of width 20-40 nm (also called the perinuclear space).

The double lipid bilayer enclosing the nucleus and separating its contents from the rest of the cytoplasm; includes the intermembrane space, a gap of width 20-40 nm (also called the perinuclear space).

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.

A compound membranous cytoplasmic organelle of eukaryotic cells, consisting of flattened, ribosome-free vesicles arranged in a more or less regular stack. The Golgi apparatus differs from the endoplasmic reticulum in often having slightly thicker membranes, appearing in sections as a characteristic shallow semicircle so that the convex side (cis or entry face) abuts the endoplasmic reticulum, secretory vesicles emerging from the concave side (trans or exit face). In vertebrate cells there is usually one such organelle, while in invertebrates and plants, where they are known usually as dictyosomes, there may be several scattered in the cytoplasm. The Golgi apparatus processes proteins produced on the ribosomes of the rough endoplasmic reticulum; such processing includes modification of the core oligosaccharides of glycoproteins, and the sorting and packaging of proteins for transport to a variety of cellular locations. Three different regions of the Golgi are now recognized both in terms of structure and function: cis, in the vicinity of the cis face, trans, in the vicinity of the trans face, and medial, lying between the cis and trans regions.

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 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.

Any dynein complex with a homodimeric dynein heavy chain core that catalyzes movement along a microtubule. Cytoplasmic dynein complexes participate in many cytoplasmic transport activities in eukaryotes, such as mRNA localization, intermediate filament transport, nuclear envelope breakdown, apoptosis, transport of centrosomal proteins, mitotic spindle assembly, virus transport, kinetochore functions, and movement of signaling and spindle checkpoint proteins. Some complexes participate in intraflagellar transport. Subunits associated with the dynein heavy chain mediate association between dynein heavy chain and cargoes, and may include light chains and light intermediate chains.

Any dynein complex with a homodimeric dynein heavy chain core that catalyzes movement along a microtubule. Cytoplasmic dynein complexes participate in many cytoplasmic transport activities in eukaryotes, such as mRNA localization, intermediate filament transport, nuclear envelope breakdown, apoptosis, transport of centrosomal proteins, mitotic spindle assembly, virus transport, kinetochore functions, and movement of signaling and spindle checkpoint proteins. Some complexes participate in intraflagellar transport. Subunits associated with the dynein heavy chain mediate association between dynein heavy chain and cargoes, and may include light chains and light intermediate chains.

Any of the long, generally straight, hollow tubes of internal diameter 12-15 nm and external diameter 24 nm found in a wide variety of eukaryotic cells; each consists (usually) of 13 protofilaments of polymeric tubulin, staggered in such a manner that the tubulin monomers are arranged in a helical pattern on the microtubular surface, and with the alpha/beta axes of the tubulin subunits parallel to the long axis of the tubule; exist in equilibrium with pool of tubulin monomers and can be rapidly assembled or disassembled in response to physiological stimuli; concerned with force generation, e.g. in the spindle.

Any multimeric complex connected to a microtubule.

Any microtubule in the cytoplasm of a cell.

The bundle of microtubules and associated proteins that forms the core of cilia (also called flagella) in eukaryotic cells and is responsible for their movements.

The bundle of microtubules and associated proteins that forms the core of cilia (also called flagella) in eukaryotic cells and is responsible for their movements.

A membrane-bounded intracellular vesicle formed by invagination of the plasma membrane around an extracellular substance. Endocytic vesicles fuse with early endosomes to deliver the cargo for further sorting.

Thin, stiff, actin-based protrusion extended by the leading edge of a motile cell such as a crawling fibroblast or amoeba, or an axonal or dendritic growth cone, or a dendritic shaft.

Any of several large complexes that contain two or three dynein heavy chains and several light chains, and have microtubule motor activity.

Any of several large complexes that contain two or three dynein heavy chains and several light chains, and have microtubule motor activity.

The long process of a neuron that conducts nerve impulses, usually away from the cell body to the terminals and varicosities, which are sites of storage and release of neurotransmitter.

The long process of a neuron that conducts nerve impulses, usually away from the cell body to the terminals and varicosities, which are sites of storage and release of neurotransmitter.

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.

A nonmembrane-bound oligomeric protein complex that participates in bidirectional transport of molecules (cargo) along axonemal microtubules.

A nonmembrane-bound oligomeric protein complex that participates in bidirectional transport of molecules (cargo) along axonemal microtubules.

The lipid bilayer surrounding an early phagosome.

The portion of a neuron that includes the nucleus, but excludes cell projections such as axons and dendrites.

The portion of a neuron that includes the nucleus, but excludes cell projections such as axons and dendrites.

A large intracellular spectrin-rich structure that has been found in insect germline cells and mammalian hematopoietic cells. The fusome is an elongated, branched structure, formed from the spherical spectrosome organelle.

The lipid bilayer surrounding a phagolysosome.

A cilium which may have a variable array of axonemal microtubules but does not contain molecular motors.

Any cytoplasm that is part of a axon.

A macromolecular complex containing both protein and RNA molecules.