Cell Cycle and Division

The cell cycle is a series of ordered events where a cell grows and divides. It is crucial for genetic stability.

Interphase (95% of the cycle)

• G1 phase: Cell growth, enzyme synthesis for replication.
• S phase: DNA replication (semi-conservative).
• G2 phase: Protein synthesis and spindle fiber preparation; error checking.

M Phase (Mitosis)

• Karyokinesis: Nuclear division (Prophase, Metaphase, Anaphase, Telophase).
• Cytokinesis: Cytoplasmic division into two cells.

Regulation and Checkpoints

• G1 Checkpoint: Checks for size, nutrients, and DNA damage.
• G2 Checkpoint: Ensures S-phase replication is complete without errors.
• M Checkpoint: Ensures proper chromosome alignment.

Disorders

• Cancer: Uncontrolled cell division often due to mutations in suppressor genes or oncogenes.