The necessary sequence of growth and synthetic stages through which a cell passes, from its origin by mitosis of a parent cell until its own division into daughter cells. It consists of a G₁ (first gap) phase, a S (synthesis) phase, a G₂ phase and a M (mitosis) phase. When the cell cycle has been temporarily interrupted, the cell is said to have entered the G₀ phase. The cell cycle has also been divided into cytologically-recognizable stages. In interphase, diploid somatic cells enter mitosis for production of daughter cells through cell division and diploid germ cells enter meiosis to form haploid gametes. In prophase the already-duplicated chromosomes become visible. In metaphase the chromosomes are aligned in the center of the cell; in anaphase the chromatids pull apart toward the poles of the cell and the cell divides (cytokinesis). The quiescent stage of the cell cycle is G₀; interphase consists of G₁, S and G₂; and mitosis is the M phase.