chromosome
/ˈkrəʊməsəʊm/noun
- Biology a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes【生】染色体。
Each chromosome consists of a DNA double helix bearing a linear sequence of genes, coiled and recoiled around aggregated proteins (histones). Their number varies from species to species: humans have 22 pairs plus the two sex chromosomes （two X chromosomes in females, one X and one Y in males）. During cell division each DNA strand is duplicated, and the chromosomes condense to become visible as distinct pairs of chromatids joined at the centromere. Bacteria and viruses lack a nucleus, and have a single chromosome without histones.
派生词
chromosomal
adjective词源
late 19th cent.: coined in German from Greek khrōma 'colour' + sōma 'body'.