Final answer:
The G2/M checkpoint ensures that DNA replication is complete and undamaged, and that necessary proteins for mitosis are produced before a cell can proceed. Proper chromosome attachment to spindle fibers is assessed at the subsequent M checkpoint.
Step-by-step explanation:
The question pertains to the cell cycle, particularly the G2/M checkpoint. The passage through the G2/M checkpoint involves verifying that all DNA replication is complete and the DNA is undamaged from the S phase. If there is damage, the cell must repair it before it can proceed to mitosis. Additionally, cells must produce necessary proteins for mitosis like those for chromosome condensation and spindle fiber formation.
The two critical aspects of this checkpoint include accurate and complete DNA replication and proper attachment of mitotic spindle fibers to kinetochores, which are assessed later at the M checkpoint. The M checkpoint, occurring at the end of metaphase, ensures that all sister chromatids are correctly attached to spindle microtubules before proceeding to the next phase, which is irreversible.