Answer: Condensin I works in cytoplasm during mitosis; condensin II works in nucleus from G 2 onward for different aspects of chromosome architecture.
- A Their physical location upon the chromosome arms alone, with no other functional distinction, with both complexes otherwise performing identical molecular roles throughout the entire cell cycle
- B Condensin I works in cytoplasm during mitosis; condensin II works in nucleus from G<sub>2</sub> onward for different aspects of chromosome architecture
- C Their relative ATP requirements during chromosome condensation, with condensin II needing far more, despite both complexes using the same SMC ATPase core to drive their condensation activity
- D The particular tissue types and cell lineages in which each complex is found expressed, even though both are ubiquitously expressed across essentially all dividing somatic cell types
Correct answer: B. Condensin I works in cytoplasm during mitosis; condensin II works in nucleus from G<sub>2</sub> onward for different aspects of chromosome architecture
Explanation: Condensin II is nuclear, loads in prophase for axial compaction. Condensin I is cytoplasmic until nuclear envelope breaks down, loading for lateral compaction. Together they shape mitotic chromosomes.
The cell cycle: G1 (growth and preparation), S (DNA replication, chromosome number stays 2n but DNA content doubles), G2 (final checks before division), and M (mitosis itself) - together, G1+S+G2 make up interphase.
Concept context
Mitosis and meiosis: how cells divide for growth, repair, and reproduction.