How do genes control the growth and division of cells?
Cells rely on a tightly regulated process called the cell cycle to ensure DNA is copied correctly and that damaged cells are repaired or removed.
The Cell Cycle
A variety of genes are involved in the control of cell growth and division. The cell replicates itself in an organized, step-by-step fashion known as the cell cycle. Tight regulation of this process ensures that:
- A dividing cell’s DNA is copied properly.
- Any errors in the DNA are repaired.
- Each daughter cell receives a full set of chromosomes.
The cell cycle includes checkpoints (also called restriction points), which allow certain genes to check for problems and halt the cycle for repairs if something goes wrong.
Apoptosis and Disease
If a cell has an error in its DNA that cannot be repaired, it may undergo self-destruction, known as apoptosis. This is a common process throughout life that helps the body remove cells that no longer work or are not needed. These cells are recycled by a type of white blood cell called a macrophage. Apoptosis protects the body by removing genetically damaged cells that could lead to cancer, and it plays an important role in the development of the embryo and the maintenance of adult tissues.
Disruption of the normal regulation of the cell cycle can lead to diseases such as cancer. When the cell cycle proceeds without control, cells can divide without order and accumulate genetic errors.