Cell division. Time-exposure light micrograph showing the different stages in mitosis (nuclear division). At left the cell is in interphase. The nucleus (round, centre) is clearly visible. As the cell moves into prophase, the nuclear envelope dissolves and the chromosomes (white) condense. By the fifth frame, the cell is in metaphase, with the chromosomes aligned along the centre of the cell. The chromosomes start to move to the opposite poles, guided by microtubules, during anaphase. In the last frame the separated chromosomes have moved to opposite ends of the cell. The cell is undergoing cytokinesis (cell division) to form two new cells.