How does the cell cycle regulate normal cell growth?

The regulation of normal cell growth during the cell cycle is primarily achieved through checkpoints and cyclins. Checkpoints are crucial control mechanisms that ensure the cell is ready to proceed to the next stage of the cycle. They assess whether the cell's DNA is intact, the cell has sufficient resources, and if the cell is adequately sized before allowing progression to division.

Cyclins are proteins that interact with cyclin-dependent kinases (CDKs) to regulate the progression through different phases of the cell cycle. Different cyclins are produced and degraded at specific times, corresponding to various phases of the cell cycle. This cyclical expression ensures that the cell only advances when certain conditions are met, thus preventing uncontrolled growth and maintaining proper cellular function.

This tightly regulated process prevents errors during cell division that could lead to cancer, where the normal growth control mechanisms fail. The cell's ability to monitor and regulate its growth via these checkpoints and cyclins emphasizes the importance of this mechanism in maintaining healthy tissue homeostasis.