That's one of the properties of mitosis, that the DNA gets completely duplicated during the S phase, during DNA synthesis phase.

有丝分裂的一个特征,就是DNA在S期内完全复制,S期就是DNA合成期

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If I followed one of them it is in a phase that's called G1 first and this is a resting phase before it enters the process of synthesizing new DNA in preparation for another round of mitosis.

如果我们跟随一个细胞前进,首先进入G1期,这是一段静息期,之后进入,合成新DNA的S期,为下一轮有丝分裂做准备

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