- A DNA repair following ultraviolet radiation damage
- B Entry into mitosis (G2 to M transition)
- C Cytokinesis and cleavage furrow formation
- D G1 arrest in response to growth factor withdrawal
Correct answer: B. Entry into mitosis (G2 to M transition)
Explanation: MPF (Cyclin B + Cdk1 complex) promotes entry into mitosis. It was the first cell cycle control protein discovered.
Concept context
Mitosis and meiosis: how cells divide for growth, repair, and reproduction.