Cell Cycle

Cell Cycle Overview

• The cell cycle encompasses the stages that a cell undergoes from birth to replication.
• It is a monumental process that ensures the continuity of life from generation to generation.
• The cell cycle consists primarily of four phases; the G1 phase, S phase, G2 phase, and the mitotic (M) phase.

Phases of the Cell Cycle

G1 Phase

• In the G1 phase, the cell grows in size and prepares to duplicate its DNA.
• The cell checks its health and the surrounding environment. A healthy environment and cell conditions are suitable for DNA duplication.

S Phase

• The S phase stands for synthesis phase. It involves the replication of chromosomes.
• By the end of this phase, each cell has two complete sets of chromosomes, preparing the cell for division.

G2 Phase

• This is another growth phase, G2 phase, where the cell prepares itself for mitosis and cytokinesis.
• The cell conducts another check to ensure it is ready and healthy enough for division.

M Phase

• The M phase encompasses mitosis and cytokinesis - the final stages of cell division.
• During mitosis, the cell’s nucleus and replicated chromosomes separate into two new nuclei.
• Cytokinesis is the process where the rest of the cell splits in two, creating two identical daughter cells.

Cycle Control and Checkpoints

• Cell cycle checkpoints verify whether processes have been accurately completed before the cell moves onto the next phase.
• Checkpoints exist at the transitions from G1 to S, G2 to M and during the M phase.
• If anything is wrong, such as damaged DNA or incomplete replication, the cell cycle can halt, and the cell can try to fix the problem or self-destruct.