CELL CYCLE AND CELL DIVISION

Every second, roughly 2 million cells divide in your body. Your body replaces approximately 300 billion cells daily. Over a year, you replace ~98% of your body mass at the cellular level. Yet despite this constant renewal, you maintain consistency—the same person today as yesterday, the same tissues with same functions.

This constancy depends on precise cellular division and replication. When division goes wrong, consequences range from developmental abnormalities to cancer. Understanding cell division reveals how organisms grow, replace damaged tissues, and reproduce.