Cytosol
The aqueous phase of the cytoplasm comprised of dissolved soluted but excluding the organelles

Cytosolic processing pathway
A pathway for processing endogenous cytosolic antigens for presentation on class I MHC.

Cytotoxic (cytolytic) T cell
A cell that kills target cells harbouring appropriate antigen within the groove of an MHC class I molecule that is identical to that of the T cell. It kills virus-infected cells and tumour cells.

Cytotype
A characteristic conferred by an agent in the cytoplasm rather than in the nucleus. This is maternally inherited. Refers to characteristics specified by cytoplasmic genes as well as those specified by the products of nuclear genes, which are synthesized in and function in the cytoplasm.

Cytoplasmic segregation
The generation of homoplasmic cells from heteroplasmic cells during mitotic division. This reflects random partition of organelle population between daughter cells, a stochastic process that leads to bias further exaggerated through rounds of division. The daughter cells are homoplasmic after several generations.

Cytoplasmic streaming
The back-and-forth movement of cytoplasm in certain algae and the circular flow of cytoplasm around a central vacuole in a plant cell. Also termed cyclosis.

Cytoplasmic trait
A genetic characteristic in which the genes are found outside the nucleus such as the mitochondria or chloroplast. This results in offspring that inherit genetic material from only one parent, usually maternal.

Cytokinesis
Cytoplasmic division and changes other than nuclear division that are a part of mitosis or meiosis. See cell division.

Cytokinin
Plant growth regulators (hormones) that stimulate cell division and cell differentiation. These compounds are derivatives of adenine. In tissue culture, these hormones are associated with enhanced callus and shoot development.

Cytological hybridization
See in situ hybridization.

Cytology
The study of the structure and function of cells.

Cytolysis
Cell disintegration.

Cytomegalovirus (CMV)
A nonpathogenic human virus that can become pathogenic in immunocompromised hosts. Following infection, the virus persists in the host. A carrier is however protected in the virus by both T-cell and humoral immunity. The CMV promoter has been incorporated into many plasmid vectors so that mammalian genes cloned can be expressed.