AP BIOLOGY

Detailed explanation-1: -Generally, however, for fast-dividing mammalian cells, the length of the cycle is approximately 24 hours. Most of the differences in cell cycle duration between species and cells are found in the duration of specific cell cycle phases. DNA replication, for example, generally proceeds faster the simpler the organisms.

Detailed explanation-2: -However, mitosis and cytokinesis last only about an hour, so approximately 95% of the cell cycle is spent in interphase-the period between mitoses.

Detailed explanation-3: -A typical proliferating human cell divides on average every 24 h. This division timing allows cells to synchronize with other physiological processes and with the environment. The circadian clock, which orchestrates daily rhythms, directly regulates the cell division cycle and is a major synchronizing factor.

Detailed explanation-4: -For a typical rapidly proliferating human cell with a total cycle time of 24 hours, the G1 phase might last about 11 hours, S phase about 8 hours, G2 about 4 hours, and M about 1 hour.