细胞增殖通过细胞周期而实现。从上一次细胞分裂结束开始到下一次细胞分裂结束为止的时间称为细胞周期。细胞周期可以依据DNA的合成与否和细胞分裂与否分为四个时相:G_1期、S期、G_2期和M期。正常细胞周期的完成,这四个时期是顺次完成的。并且表现为前一时期为后一时 Cell proliferation is achieved through the cell cycle. The time from the end of the last cell division to the end of the next cell division is called the cell cycle. The cell cycle can be divided into four phases according to whether DNA is synthesized or not and cell division or not: G1 phase, S phase, G2 phase, and M phase. The completion of the normal cell cycle, these four periods are completed in sequence. And it shows that the former period is the latter