During which phase does DNA replication take place?

DNA replication occurs during the S phase of interphase. The S phase, or synthesis phase, is specifically designated for the replication of DNA, where each chromosome is duplicated, resulting in two sister chromatids for each chromosome. This process is essential for ensuring that when a cell divides, each daughter cell receives an identical set of chromosomes.

During this phase, the DNA unwinds, and enzymes such as DNA polymerase synthesize the new strands by adding complementary nucleotides. This meticulous process allows for the accurate duplication of genetic material, setting the stage for cell division in the subsequent M phase (mitosis).

In contrast, the G1 phase primarily involves the cell's growth and preparation for DNA synthesis, while the G2 phase focuses on further cell growth and final preparations for mitosis. The M phase is where actual cell division occurs, which separates the duplicated chromosomes into the new daughter cells. Therefore, the S phase is uniquely responsible for the essential process of DNA replication.