Final answer:
The cell cycle in the fission yeast Saccharomyces cerevisiae is regulated primarily at the G2 to M transition, where cell size and nutrient availability are monitored. Internal controls called checkpoints regulate the cell cycle, with the G2/M checkpoint playing a crucial role.
Step-by-step explanation:
In the fission yeast, Saccharomyces cerevisiae, the cell cycle is regulated primarily by the control of the G2 to M transition, at which cell size and nutrient availability are monitored. The cell cycle consists of several phases, including G1, S, and G2, and is regulated by internal controls called checkpoints. The G2/M checkpoint is particularly important in ensuring that the cell is ready to enter mitosis and divide.