Cell life cycle. Labelled animation showing the stages in a cell's life cycle, indicated by the coloured circular bar. The two stages are interphase (the non-dividing 'normal' phase) and mitosis (the process of cell division). Three sub-stages of interphase are illustrated here: Gap 1 (dark blue), S phase (blue), and Gap 2 (light blue). The cycle is completed by mitosis (red). The cell is shown with its nucleus (orange) and genetic material (chromosomes, red and blue). During Gap 1 (G1), the normal biological functions supporting life take place, such as respiration and translation of genetic instructions. During the S phase, replication of the DNA (deoxyribonucleic acid) results in a copy being formed of the chromosomes. During Gap 2 (G2), the cell grows and a check occurs of the DNA, with damage being repaired before mitosis takes place. During mitosis, the nuclear membrane dissolves, the chromosomes separate, and the cell divides (cytokinesis). The nuclear membranes reform in the two identical daughter cells. For this animation without labels, see clip K004/6136. |