Short answers, pulled from the story.
A single human cell spends roughly 91% of its life in a state called interphase. This long period includes three distinct phases: G1, S, and G2, followed by the M phase where actual division occurs.
Leland Hartwell, Tim Hunt, and Paul Nurse won the 2001 Nobel Prize for discovering the molecular engines that drive these cycles forward. These researchers identified cyclins and cyclin-dependent kinases as the central regulators controlling progression through specific checkpoints.
Approximately one percent of single-strand DNA damages convert into about 50 endogenous double-strand breaks per cell cycle in normal human cells. These errors usually repair with high fidelity, but mistakes contribute significantly to cancer rates.
Scientists developed synthetic inhibitors like palbociclib, ribociclib, and abemaciclib to treat advanced-stage breast cancer. These drugs received FDA approval for hormone-receptor-positive, HER2-negative breast cancer cases.
Modern yeast rely on just one CDK such as Cdc28 in Saccharomyces cerevisiae to control their entire cell cycle. Animals evolved whole families of CDKs including Cdk1, Cdk2, Cdk4, and Cdk6 to regulate different phases like mitosis and S phase entry.