In which phase of the cell cycle does DNA replication occur?

DNA replication occurs during the S phase of the cell cycle. This phase is specifically designated for the synthesis of DNA, where each chromosome is duplicated to ensure that when the cell divides, each daughter cell has an identical set of chromosomes. This process is crucial for maintaining genetic consistency across generations of cells.

During the S phase, the DNA double helix unwinds and separates, allowing the synthesis of new complementary strands for each original strand. This is essential for cellular division and overall organism growth and repair. The successful completion of DNA replication is a key factor that prepares the cell for the following phases, particularly the G2 phase, where the cell checks the replication process for errors and prepares for mitosis.