Final answer:
Colchicine is a poison that disrupts the formation of spindle fibers, leading to the a) inhibition of chromosome segregation during mitosis. By binding to tubulin, colchicine prevents spindle fiber assembly, arresting cell division typically at the metaphase stage.
Step-by-step explanation:
Colchicine is a compound known to inhibit the development of spindle fibers during cell division. Spindle fibers are essential structures that form during mitosis, specifically during the prophase to metaphase transition, and play a critical role in chromosome segregation.
These microtubular fibers, composed of the protein tubulin, are responsible for pulling duplicated chromosomes to opposite poles of the cell, ensuring that each daughter cell receives an identical set of chromosomes.
When colchicine is introduced to a cell, it binds to tubulin, inhibiting the formation and function of spindle fibers. As a result, the chromosomes do not properly align at the cell's equatorial plate during metaphase, and they cannot be segregated into the daughter cells. This interruption in the delicate process of mitosis results in the arrest of cell division, typically at the metaphase stage where chromosomes are most visibly affected by the lack of functional spindles.
The correct response to the question about the effects of colchicine on mitosis is therefore (a) Inhibition of chromosome segregation. Without spindle fibers, chromosomes cannot be pulled apart, which inhibits their segregation to the forming daughter cells and effectively halts mitosis.