During what phase of the cell cycle does DNA duplication occur?

DNA duplication occurs during the S phase of the cell cycle, which stands for "synthesis." This phase is specifically designated for the replication of the cell's DNA, ensuring that each daughter cell will receive an identical set of genetic information after cell division. During the S phase, the chromosomes are duplicated, resulting in two sister chromatids for each chromosome. This process is crucial for maintaining the integrity of the genetic material as it prepares for the subsequent phases of the cell cycle. After the S phase, the cell enters the G2 phase, where it prepares for mitosis, and this preparation includes checking the duplicated DNA for any errors. The G1 phase occurs before DNA synthesis, and the M phase is where the actual division of the cell takes place, not the duplication of DNA.