Clocked cell cycle clocks.
The cell division cycle of both mammalian cells and microorganisms, which apparently has both deterministic and probabilistic features, is a clock of sorts in that the sequence of events that comprise it measures time under a given set of environmental conditions. The cell division cycle may itself be regulated by a programmable clock that, under certain conditions, can generate circadian periodicities by interaction with a circadian pacemaker. These clocks must insert time segments into the cell division cycle in order to generate the observed variability in cellular generation times.
D000818:Animals; D001683:Biological Clocks; D002453:Cell Cycle; D002940:Circadian Rhythm; D004261:DNA Replication; D008027:Light; D008938:Mitosis; D010507:Periodicity; D011336:Probability