Answer: Prevents spindle fibre formation.
- A Prevents spindle fibre formation
- B Speeds up DNA replication
- C Blocks DNA repair enzymes
- D Triggers programmed cell death
Correct answer: A. Prevents spindle fibre formation
Explanation: Colchicine binds tubulin and blocks assembly of the spindle microtubules, so cells cannot move past metaphase.
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.