Which statement best describes the G2 checkpoint?

Which statement best describes the G2 checkpoint?

• A. A checkpoint that ensures chromosome condensation is complete.
• B. A checkpoint that verifies DNA replication has occurred accurately without errors prior to mitosis.
• C. A checkpoint that checks spindle fiber formation during anaphase.
• D. A checkpoint that ensures nuclear envelope reformation after mitosis.

Answer: (B)

The G2 checkpoint is the cell’s quality control before entering mitosis; it makes sure that DNA replication is complete and that any DNA damage has been repaired. This is why the best description is that it verifies DNA replication has occurred accurately without errors prior to mitosis. If problems are found, the cell cycle stops so repairs can be made, preventing transmission of mutations. Chromosome condensation happens as cells prepare for mitosis, not at the G2 checkpoint. The checkpoint that monitors spindle formation and proper chromosome–spindle attachments occurs later, before anaphase, and ensures chromosomes are lined up correctly. Nuclear envelope reformation occurs after mitosis, during telophase, not at the G2 checkpoint.

The G2 checkpoint is the cell’s quality control before entering mitosis; it makes sure that DNA replication is complete and that any DNA damage has been repaired. This is why the best description is that it verifies DNA replication has occurred accurately without errors prior to mitosis. If problems are found, the cell cycle stops so repairs can be made, preventing transmission of mutations.

Chromosome condensation happens as cells prepare for mitosis, not at the G2 checkpoint. The checkpoint that monitors spindle formation and proper chromosome–spindle attachments occurs later, before anaphase, and ensures chromosomes are lined up correctly. Nuclear envelope reformation occurs after mitosis, during telophase, not at the G2 checkpoint.