Final answer:
Key regulators of the G1-S transition are cyclins and cyclin-dependent kinases (Cdks). Unscheduled bypass is the result of a faulty regulatory control in the cell cycle, leading to uncontrolled cell division and the potential development of cancer.
Step-by-step explanation:
The key regulators of the G1-S transition are cyclins and cyclin-dependent kinases (Cdks). Cyclins and Cdks are internal molecular signals that regulate cell transitions through the various checkpoints in the cell cycle.
When cyclins and Cdks are activated, they allow the cell cycle to advance to the next stage. However, the cell cycle is also regulated by negative regulator proteins such as retinoblastoma protein (Rb), p53, and p21. These proteins monitor cellular conditions and can halt the cell cycle until specific requirements are met.
Unscheduled bypass is the result of a faulty regulatory control in the cell cycle. It occurs when the negative regulators fail to stop the cell cycle progression, leading to uncontrolled cell division and the potential development of cancer.