In which phase do eukaryotic cells replicate their DNA?

Eukaryotic cells replicate their DNA during the S phase, which stands for synthesis phase. This phase is a crucial part of the cell cycle, where the entire genetic material is duplicated to ensure that each daughter cell receives an identical set of chromosomes during cell division. During S phase, the cell prepares for mitosis (or meiosis) by synthesizing new DNA strands, effectively doubling the amount of genetic material.

In contrast, the G1 phase is primarily focused on cell growth and preparation for DNA synthesis, while the G2 phase involves further growth and preparation for mitosis, including the synthesis of proteins necessary for mitosis to occur. The M phase is when mitosis and cytokinesis take place, which is the actual division of the cell, not the replication of DNA. Therefore, the S phase is uniquely dedicated to the essential process of DNA replication.