 During its lifetime , a nucleus may be broken down or destroyed , either in the process of cell division or as a consequence of apoptosis ( the process of programmed cell death ) . During these events , the structural components of the nucleus — the envelope and lamina — can be systematically degraded . In most cells , the disassembly of the nuclear envelope marks the end of the <unk> of mitosis . However , this disassembly of the nucleus is not a universal feature of mitosis and does not occur in all cells . Some <unk> eukaryotes ( e.g. , <unk> ) undergo so @-@ called closed mitosis , in which the nuclear envelope remains intact . In closed mitosis , the daughter chromosomes migrate to opposite poles of the nucleus , which then divides in two . The cells of higher eukaryotes , however , usually undergo open mitosis , which is characterized by breakdown of the nuclear envelope . The daughter chromosomes then migrate to opposite poles of the <unk> spindle , and new nuclei <unk> around them . 
