MITOSIS. MITOSIS Meristem of an onion root composed of undifferentiated embryonic cells. Mitosis (cell division) is active in the meristem allowing the root to lengthen. Chromosomes (*) in the mother cell are duplicated during mitosis leading to the formation of two daughter cells with the same chromosomes. There are four phases of mitosis: prophase (chromosome contraction and duplication), metaphase (arrangement of the chromosomes along the equatorial plane of the spindle), anaphase (separa