cellular component
component of a cell
plasma membrane
biological membrane that separates the interior of a cell from its outside environment
nucleolus
largest structure in the nucleus of eukaryotic cells
X chromosome
sex chromosome present in both sexes, of species in which the male is the heterogametic sex
immunological synapse
area of close contact between a lymphocyte and a target cell
chromatin
the ordered and organized complex of DNA, protein, and sometimes RNA in cell nucleus
autosome
Any chromosome other than a sex chromosome
cell junction
a cellular component that forms a specialized region of connection between two or more cells, or between a cell and the extracellular matrix, or between two membrane-bound components of a cell, such as flagella
vesicle
any small, fluid-filled, spherical organelle enclosed by a membrane
flagellum
cellular appendages functioning as locomotive or sensory organelles
spectrin
cytoskeletal protein
sex chromosome
chromosome involved in sex determination
synaptic vesicle
secretory organelle in neurons that stores neurotransmitters that are released at the synapse
mitochondrial crista
any of the inward folds of the mitochondrial inner membrane
spine apparatus
cellular component, form of endoplasmic reticulum
axon terminus
terminal inflated portion of the axon, containing the specialized apparatus necessary to release neurotransmitters
lamella
in cellular biology, thin layer, membrane, or plate of tissue
radial spoke
protein structure in cilia and flagella
Ski complex
protein complex that regulates RNA degradation by the exosome complex. In Saccharomyces the complex has a heterotetrameric stoichiometry consisting of one copy each of Ski2p and Ski3 and two copies of Ski8p
membrane
a lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it
transport vesicle
Any of the vesicles of the constitutive secretory pathway, which carry cargo from the endoplasmic reticulum to the Golgi, between Golgi cisternae, from the Golgi to the ER (retrograde transport) or to destinations within or outside the cell.
contractile fiber
Fibers, composed of actin, myosin, and associated proteins, found in cells of smooth or striated muscle.
collagen type I trimer
a collagen trimer containing alpha(I) chains
mediator complex
protein complex that interacts with the carboxy-terminal domain of the largest subunit of RNA polymerase II
Golgi transport complex
multisubunit tethering complex of the CATCHR family (complexes associated with tethering containing helical rods) that has a role in tethering vesicles to the Golgi prior to fusion. In yeast, this complex is called the Sec34/35 complex and is comp
microprocessor complex
protein complex that binds to heme and to pri-miRNAs, and is required for the formation of a pre-microRNA (pre-miRNA), the initial step of microRNA (miRNA) biogenesis. The complex is composed of the double-stranded-RNA-specific RNase Drosha (also c
DNA replication factor A complex
conserved heterotrimeric complex that binds nonspecifically to single-stranded DNA and is required for multiple processes in eukaryotic DNA metabolism
SAGA complex
SAGA-type histone acetyltransferase complex that contains Spt8 (in budding yeast) or a homolog thereof; additional polypeptides include Spt group, consisting of Spt7, Spt3, and Spt20/Ada5, which interact with the TATA-binding protein (TBP); the Ada
type II protein secretion system complex
large protein complex that spans the cell envelope of Gram-negative bacteria and mediates the movement of proteins into the extracellular environment
GINS complex
heterotetrameric protein complex that associates with replication origins, where it is required for the initiation of DNA replication, and with replication forks
signal peptidase complex
protein complex that is located in the endoplasmic reticulum membrane and cleaves the signal sequence from precursor proteins following their transport out of the cytoplasmic space
DNA polymerase V complex
complex that contains two UmuD' and one UmuC subunits, and acts in translesion DNA synthesis
spike protein
short structure attached to an icosahedral virion capsid, and used for attachment to the host cell
collagen
group of fibrous proteins that occur in vertebrates as the chief constituent of connective tissue fibrils and in bones and yield gelatin and glue upon boiling with water
nuclear pore
discrete opening in the nuclear envelope of a eukaryotic cell
protoplasm
part of cell
plastid
membrane-bound DNA-containing organelle found in the cytoplasm of autotrophic eukaryotes (plants, some protists)
axon
long projection on a neuron that conducts signals to other neurons
cilium
organelle found on eukaryotic cells
cellular compartment
closed part in cytosol
cell surface
external part of the cell wall or plasma membrane
synaptic cleft
The narrow gap that separates the presynaptic and postsynaptic membranes, into which neurotransmitter is released.
anaphase-promoting complex
ubiquitin ligase complex that degrades mitotic cyclins and anaphase inhibitory protein, thereby triggering sister chromatid separation and exit from mitosis. Substrate recognition by APC occurs through degradation signals, the most common of which
intermediate filament
cytoskeletal structure
nuclear membrane
membrane part of the nuclear envelope
neuromuscular junction
junction between the axon of a motor neuron and a muscle fiber
chromoplast
plastid containing pigments other than chlorophyll, usually yellow and orange carotenoid pigments
focal adhesion
small region on the surface of a cell that anchors the cell to the extracellular matrix and that forms a point of termination of actin filaments
nuclear matrix
the dense fibrillar network lying on the inner side of the nuclear membrane
macronucleus
type of nucleus in ciliates, involved in non-reproductive cell functions