Cell Growth and Reproduction Cell Reproduction All cells come from preexisting cells. Cell division results in two cells that are identical to the parent cell. New cells are constantly being produced. Scientists noticed certain structures that appeared just before cell division and disappeared after. Chromosomes: structures which contain DNA and become darkly colored when stained For most of a cell?s life, chromosomes exist as chromatin Chromatin: long strands of DNA wrapped around proteins called histones Histones are grouped in bunches called nucleosomes The Cell Cycle Cell cycle: the sequence of growth and division of a cell Two general periods of the cycle: growth and division The majority of a cell?s life is spent in the growth period known as interphase