See Also: molecular clock(medicine)
ten-o'clock(medicine)
around-the-clock(dictionary)
four-o'clock(encyclopedia)
Four-o'clock(medicine)
clock(encyclopedia)
o'clock(dictionary)
o'clock(dictionary)
clock(6)(dictionary)
clock(5)(dictionary)

polyatomic (iou) and molecular clock (medicine)


polyatomic (iou)



polyatomic adjective. M19.
[from POLY- + ATOMIC.]
Chemistry. Containing three or more atoms; composed of molecules each containing three or more atoms. Also, polybasic, polyvalent.

molecular clock (medicine)


molecular clock


This term has two separate uses.

1. <molecular biology> The rate of fixation of mutations in DNA and thus times the rate of genetic diversification.

2. <cell biology> A biological system capable of maintaining up a timing rhythm or pulse. All such clocks are thought to be entrained by a natural oscillator such as the diurnal rhythm.