An onion root tip cell is treated with a chemical that prevents microtubule polymerization. What will be the resulting chromosome number in the cell after the centromeres split in a failed division cycle, and which specific mitotic event is directly prevented by this treatment?

Step-by-step solution

The normal diploid chromosome number ( 2n ) for an onion root tip cell is 16. During the S-phase of the cell cycle, DNA replication occurs, but the chromosome number remains 16. During mitosis, the centromeres split at the onset of anaphase, converting each sister chromatid into an individual chromosome. This temporarily doubles the chromosome number to 32 in the cell. Microtubules are the structural components of spindle fibers. A chemical that prevents microtubule polymerization destroys the mitotic spindle appar