The stage at which DNA/chromosome replication occurs is
During the cell replication cycle, there are two major "phases" that the cell goes through. The beginning and majority of the time is known as interphase. Interphase is 80% of the total cycle and is where the cell does most of the work in replicating organelles, chromosomes and preparing to undergo mitosis which is the actual splitting process where one cell becomes two. During interphase, there are 3 major steps, G1, S and the G2 phase. In the G1 phase, the cell begins creating all of the proteins required to build chromosomes and DNA.