Chi-square
A statistical procedure that enables the investigator to determine how closely an experimentally obtained set of values fits a given theoretical expectation.

Chorionic Villus Sampling
A procedure used for prenatal diagnosis in which a sample of the placenta, specifically the villous area of the chorion, is withdrawn either transabdominally or transcervically.

Chloroplast
A structure (or organelle) found in some cells of plants; its function is photosynthesis.

Chordate
A member of the phylum Chordata, which includes the tunicates, lancelets, and vertebrates. They are animals with a hollow dorsal nerve cord; a rod like notochord that forms the basis of the internal skeleton; and paired gill slits in the wall of the pharynx behind the head, although in some chordates these are apparent only in early embryonic stages. All vertebrates are chordates, but the phylum also contains simpler types, such as sea-squirts, in which only the free-swimming larva has a notochord.

Chromatid
In mitosis or meiosis, one of the two identical subunits, joined at the centromere, resulting from replication of a chromosome.
2. The two daughter strands of a duplicated chromosome that are joined by a single centromere; upon division of the centromeres, the sister chromatids become separate chromosomes