DNA synthesis takes place during_________ phase

The correct answer is S phase.

To understand when DNA synthesis occurs, let us break down the stages of the cell cycle:
The cell cycle is divided into two main parts: Interphase (the preparation phase) and the M phase (Mitosis, the division phase).

Interphase is further divided into three distinct phases:

• G₁ phase (Gap 1): This is the period of cell growth and intense metabolic activity. The cell synthesizes proteins and RNA, preparing itself for DNA replication, but no DNA replication occurs yet.
• S phase (Synthesis phase): During this phase, DNA replication (synthesis) takes place. The amount of DNA in the cell doubles (from 2C to 4C, for example), ensuring that the two future daughter cells will receive identical copies of the genetic material. Centrioles also replicate in the cytoplasm during this stage.
• G₂ phase (Gap 2): This is the second growth phase where the cell synthesizes proteins (such as tubulin for spindle fibers) and prepares for cell division (M phase).

M phase (Mitosis): This is the phase of actual nuclear and cellular division where the replicated chromosomes are separated into two new nuclei.

Therefore, DNA synthesis takes place specifically during the S phase (Synthesis phase) of the cell cycle.