The G1, S, G2, and M phases represent distinct stages of the cell cycle.

The cell cycle is a series of events that lead to cell division and replication. The first phase, known as the G1 phase (Gap 1), is characterized by cell growth and preparation for DNA replication. During this phase, the cell assesses its DNA for damage and initiates repair mechanisms if necessary. Once the cell is adequately prepared, it progresses to the S phase.

The S phase, or Synthesis phase, is where DNA replication occurs. In this phase, each chromosome is duplicated, resulting in two identical sister chromatids for each chromosome. Following the completion of the S phase, the cell transitions into the G2 phase.

The G2 phase (Gap 2) serves as the second gap phase, during which the cell continues to grow and further prepares for division. The cell conducts checks for any errors that may have arisen during DNA replication, correcting any mistakes before proceeding. Once the cell is fully prepared, it enters the M phase.

The M phase, or Mitotic phase, is the stage where the cell divides into two daughter cells. This phase is comprised of two key processes: mitosis and cytokinesis. During mitosis, the duplicated chromosomes are segregated and moved to opposite poles of the cell. In the subsequent process of cytokinesis, the cell membrane constricts, ultimately dividing the cell into two separate daughter cells.

In summary, the G1, S, G2, and M phases are critical stages of the cell cycle, each encompassing specific events and functions. A thorough understanding of these phases is essential for grasping the mechanisms of cell division and the regulation of cellular growth.