Cell Culture

The cell cycle is the life of a dividing cell. Most of it is interphase (G₁ growth, S DNA synthesis, G₂ preparation), followed by mitosis and cytokinesis.

The cell cycle, with checkpoints that must pass before division continues.

Checkpoints act as quality control — if DNA is damaged, the cycle halts. Cell division is regulated by internal and external signals, including hormones. When the controlling genes mutate (from carcinogens), division runs unchecked — this is cancer.

Cell culture

Humans culture cells — grow them outside the body in controlled nutrient conditions — to make vaccines, test drugs, grow tissues and research disease. Limitations include contamination, cost, and cultured cells behaving differently from cells in a living organism.