S phase

S phase (or synthesis phase) is a period in the cell cycle during which DNA replication occurs. It succeeds the G1 phase and precedes the G2 phase. Normally, the S phase lasts for 10-12 hours in most cells.

Overview

During the S phase, the cell's DNA is replicated. This process is crucial for the cell division that follows in the M phase. The S phase is part of the interphase of the cell cycle, which also includes the G1 and G2 phases.

DNA Replication

DNA replication is the process by which a cell duplicates its DNA. This process is essential for cell division, as each new cell needs a complete set of DNA. During the S phase, the cell's DNA is unwound by enzymes, and each strand is used as a template for the synthesis of a new, complementary strand.

Regulation

The S phase is tightly regulated to ensure that DNA replication occurs accurately and only once per cell cycle. This is achieved through the action of various proteins and enzymes, including cyclins and cyclin-dependent kinases.

Clinical Significance

Abnormalities in the S phase can lead to cancer and other diseases. For example, if DNA replication is not properly regulated, it can lead to mutations and genomic instability, which can contribute to the development of cancer.

See Also

• Cell cycle
• DNA replication
• Interphase
• G1 phase
• G2 phase
• M phase

S_phase

• 
  Asymmetry in the synthesis of leading and lagging strands
• 
  Steps in DNA synthesis
• Nucleosome Duplication
  Nucleosome Duplication