Here's a breakdown of the cell cycle phases:

* Interphase: This is the longest phase of the cell cycle, where the cell grows and copies its DNA. It's further divided into three sub-phases:

* G1 phase (First Gap): The cell grows and carries out normal functions.

* S phase (Synthesis): DNA replication occurs.

* G2 phase (Second Gap): The cell continues to grow and prepares for mitosis.

* M phase (Mitotic phase): This is the phase where the cell divides. It includes:

* Mitosis: The process of nuclear division.

* Cytokinesis: The process of cell division, where the cytoplasm splits.

So, to summarize, DNA replication is a crucial event that happens exclusively during the S phase of the cell cycle, ensuring that each daughter cell receives a complete copy of the genetic material.