<P> The cell cycle or cell - division cycle is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells . In bacteria, which lack a cell nucleus, the cell cycle is divided into the B, C, and D periods . The B period extends from the end of cell division to the beginning of DNA replication . DNA replication occurs during the C period . The D period refers to the stage between the end of DNA replication and the splitting of the bacterial cell into two daughter cells . In cells with a nucleus, as in eukaryotes, the cell cycle is also divided into three periods: interphase, the mitotic (M) phase, and cytokinesis . During interphase, the cell grows, accumulating nutrients needed for mitosis, preparing it for cell division and duplicating its DNA . During the mitotic phase, the chromosomes separate . During the final stage, cytokinesis, the chromosomes and cytoplasm separate into two new daughter cells . To ensure the proper division of the cell, there are control mechanisms known as cell cycle checkpoints . </P> <P> The cell - division cycle is a vital process by which a single - celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed . After cell division, each of the daughter cells begin the interphase of a new cycle . Although the various stages of interphase are not usually morphologically distinguishable, each phase of the cell cycle has a distinct set of specialized biochemical processes that prepare the cell for initiation of cell divisions . </P>

State during which phase of the cell cycle dna replication occurs