Answer: Inhibiting separase (which would cleave cohesin).
- A Forming a direct physical bridge between sister chromatids
- B Inhibiting separase (which would cleave cohesin)
- C Nucleating spindle microtubules at the centrosome
- D Adding phosphate groups onto condensin II subunits
Correct answer: B. Inhibiting separase (which would cleave cohesin)
Explanation: Securin inhibits separase. At anaphase onset, APC/C degrades securin, freeing separase to cleave cohesin Scc1 subunit, triggering sister chromatid separation.
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.