Mitotic phase of cell cycle of eukaryotic cells, as distinct from the remainder, which is known as interphase (and that can be further subdivided as G1, s and G2). Beginning of M is signalled by separation of centrioles, where present and by the condensation of chromatin into chromosomes. M phase ends with the establishment of nuclear membranes around the two daughter nuclei, normally followed immediately by cell division (cytokinesis).
(18 Nov 1997)