Next, during anaphase 后期, the two sister chromatids of each chromosome split, and one from each pair is drawn toward each pole of the During telophase 末期 nuclear envelopes 包膜 begin to form around each set of chromosomes, and division of the cytoplasm takes 生物学家将有丝分裂划分为4个阶段。分裂前期,高度浓缩的两个染色单体通过着丝粒连接在一起。在分裂前期后期和分裂中期前期,浓缩的染色体与纺锤体相连,最后以正确的角度排列在赤道板上。在分裂后期,两个姊妹单体分离,分别拽向细胞两极。在分裂末期,在每套染色体周围形成核膜,细胞质发生分裂。