Interphase occurs between mitotic cycles, and lasts from the end of one cell division to the beginning of the next. Interphase may be called the resting stage, but a cell is never at rest. During interphase the cell grows in size, and more nucleic acids, proteins, and cellular organelles are produced. Chromosomes gradually shorten and thicken, and become visible as double stranded chromosomes. The nuclear membrane and nucleoli fade away.
Spindle fibers develop and attach to centromeres.
Chromosomes line up individually on the equator. The spindle fibers shorten and pull the duplicate chromosomes to opposite sides of the cell. There is one complete set of chromosomes at each end of the cell. Chromosomes become longer, thinner and more compact. Nuclear membrane and nucleoli reappear.