Story 1: Cell Cycle Clock

The fission yeast cell cycle progresses through G1, S, G2, and M phases, guided by a cell cycle clock that precisely times each step. Checkpoints act as “guards,” ensuring DNA is accurately replicated and chromosomes are properly segregated. During S phase, DNA is duplicated, and in M phase, mitosis and cytokinesis produce two genetically identical daughter cells, maintaining proper growth and division.

This Cell Cycle Clock figure illustrates the transitions through the four phases: the red pointer indicates the current phase, while the black pointer shows the previous phase.