The cell cycle is divided into two main parts: interphase and cell division. Interphase is the period in which the cell is performing normal functions and not actively engaged in cell division. Most of your body\'s cells spend a lot of their time in interphase. Before a cell can divide, what must occur during interphase? The sister chromatids separate into chromosomes. Each chromatin fiber is duplicated in the nucleus. The cell only performs its normal cell functions. The DNA relaxes into chromosomes. Solution During interphase ,before a cell can devide,EACH CHROMATIN FIBRE IS DUPLICATED IN THE NUCLEUS. (The duration of cell cycle when a cell is preparing itself to duplicate is called interphase. The cell does not show any activity or changes but synthesis is continued.Chromosome material is doubled,cell size is almost doubled. 4phases of interphase-.Gap1 (G1),GAP0(G0),Synthetic(S),GAP 2(G2) During s-phase,all of the cells genetic material is duplicated..