The cell cycle is the cycle in which a cell alternates between growth and then actively dividing into daughter cells. The time between divisions varies between minutes, months or even years, depending on the type of cell. The time between divisions is called Interphase. It has three stages. After a cell has divided, the two daughter cells are smaller than the original cell. They immediately begin interphase. G1 is the first stage of interphase--a period of growth in which cellular organelles are constructed. This sythesis phase makes the cells increase in size. Next is the S phase, in which chromosomes are replicated. This stage is followed by G2, which prepares the cell to divide. Next, the cell enters the mitosis phase. The steps include prophase, where the chromosomes condense, nuclear envelope disappears and centrioles divide and move to opposite poles. Spindle fibers form and attach to chromosome pairs, or chromatids, at their centromere. Metaphase is when chromosome pairs line up in the equator of the cell. During anaphase, the chromosome pairs or chromatids begin to separate. Telophase is when the chromosomes are pulled to opposite poles of the cell, the membrane begins to pinch and the nuclear envelope re-forms. In cytokinesis, the membrane completely pinches off into two daughter cells, smaller but genetically identical to the parent cell.