Which of the following is NOT one of the three main requirements for a successful cell cycle?

The correct option indicates that "Entrance into the GO phase" is not one of the three main requirements for a successful cell cycle. In the context of the cell cycle, the primary phases are G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). The GO phase, or quiescent phase, is indeed a state where cells can exit the cycle and remain metabolically active but not actively dividing. Thus, while some cells do enter the GO phase, it is not a requirement for a successful cell cycle, particularly for those cells that are actively dividing.

In contrast, the other choices presented describe key aspects of the proper orchestration of cell division. The requirement that "S phase proceeds M phase" reflects the necessity for DNA replication to occur before mitosis, ensuring that each daughter cell receives a complete set of genetic material. The requirement to be "responsive to checkpoint controls" is crucial because these checkpoints regulate the progression of the cell cycle, preventing cells from dividing with damaged DNA or other cellular issues. Finally, the notion of maintaining a "balanced growth and division in terms of mass per DNA ratio within the cytoplasm” ensures that cells grow appropriately in size and that cellular components are