Final answer:
The regulatory systems of the cell cycle ensure the creation of progeny cells with correct DNA and size, which is crucial for the health of an organism, preventing mutations and cancer.
Step-by-step explanation:
The tight regulatory mechanisms that control progression through the cell cycle in mammals serve the purpose of ensuring the formation of progeny cells containing the right amount of DNA and exhibiting the right size in all organs and tissues. This is critical to maintaining the health of an organism. Regulatory proteins control the cycle at key checkpoints to ensure the cell completes the prior phase before proceeding, preventing mistakes in DNA duplication or distribution which could lead to mutations and possibly cancer.
Control of the cell cycle is a highly refined system with internal and external signals providing 'stop' and 'advance' instructions to manage the transition between phases. Checkpoints near the end of G1, at the G2/M transition, and during metaphase are particularly crucial. These mechanisms are not only vital for the accurate replication and health of cells but also play a preventive role against unchecked cell division which can lead to illnesses such as cancer.