Phases of Mitosis Practice Test

The three classes are kinetochore microtubules, polar microtubules, and astral microtubules. Kinetochore microtubules attach to chromosomes at the kinetochores, and their dynamics help move chromosomes toward the metaphase plate and then pull sister chromatids apart during anaphase. Polar microtubules extend from each pole toward the center and interact with microtubules from the opposite pole; their overlap at the spindle midzone, coordinated by motor proteins, helps push the poles apart and elongate the spindle. Astral microtubules radiate toward the cell cortex, anchor to the cortex, and help position and orient the spindle within the cell by pulling on the cortex. Together, these three classes organize spindle assembly and drive accurate chromosome segregation.