The S Phase: When DNA Is Synthesized in the Cell Cycle
The cell cycle is a tightly regulated sequence of events that leads to cell growth and division. Among its distinct stages, one stands out as the central moment where the genetic material is duplicated: the synthesis phase, commonly abbreviated as S phase. Day to day, during this phase, the cell replicates its DNA in an exact manner, ensuring that each daughter cell receives an identical copy of the genome. Understanding during which phase of cell cycle is DNA synthesized is fundamental for students of biology, medicine, and biotechnology, as errors in this process can lead to mutations, cancer, or developmental abnormalities. The S phase occurs within interphase, the preparatory period before mitosis, and is characterized by precise enzymatic activity, checkpoint controls, and the unwinding and copying of the double helix.
Following the G1 gap phase, where
