细胞周期是细胞从一个分裂开始，经过一系列有序的生命周期阶段，最终完成一次分裂的过程。包括有丝分裂（M 期）和间期（G1、S、G2 三个阶段）。在 S 期，DNA 合成复制；在 G2 期，准备进入有丝分裂；有丝分裂完成后，进入 G1 期。细胞周期的调控受到多个细胞周期蛋白和激酶的精密调节，确保细胞分裂的有序进行。研究细胞周期对于理解细胞生物学、癌症发生机制和药物治疗具有重要意义。

The cell cycle is a process in which a cell begins with division, passes through a series of orderly life cycle stages, and finally completes one division. Including mitosis (M phase) and interphase (G1, S, G2). In S phase, DNA is synthesized and replicated; in G2 phase, it prepares to enter mitosis; after mitosis is completed, it enters G1 phase. The regulation of the cell cycle is precisely regulated by multiple cell cycle proteins and kinases to ensure the orderly progress of cell division. Studying the cell cycle is of great significance to understanding cell biology, cancer mechanisms and drug treatment.