Celcyclus

Celcyclus, often translated as the cell cycle in English, is the ordered sequence of events by which a eukaryotic cell grows, replicates its DNA, and divides. It coordinates cell growth with DNA replication and division to ensure genetic material is accurately transmitted to daughter cells. The cycle is typically divided into interphase and the M phase. Interphase includes G1 (gap1), S (DNA synthesis), and G2 (gap2). During G1 the cell grows and assesses environmental conditions; the S phase duplicates the genome; G2 provides further growth and checks for DNA replication errors. A cell may enter a quiescent G0 state from G1, reducing metabolic activity and division.

M phase encompasses mitosis, where chromosomes condense and segregate, and cytokinesis, which splits the cytoplasm and cell body. Mitosis is subdivided into prophase, prometaphase, metaphase, anaphase, and telophase, followed by cytokinesis.

Regulatory mechanisms ensure orderly progression. Cyclin-dependent kinases (CDKs) paired with regulatory cyclins drive transitions between phases. For example, Cyclin D-CDK4/6 promotes G1 progression; Cyclin E-CDK2 triggers the G1/S transition; Cyclin A-CDK2 participates in S and G2; Cyclin B-CDK1 drives entry into mitosis. Checkpoints monitor DNA integrity and spindle assembly: the G1/S checkpoint, the intra-S checkpoint, the G2/M checkpoint, and the spindle assembly checkpoint prevent progression with damaged DNA or missegregation.

Deregulation of the celcyclus is a hallmark of cancer, and many therapies target cell-cycle regulators. The concept and terminology vary by language, with celcyclus commonly used in some European languages to describe the same process as the English term cell cycle.