Spindle fibers attach to chromosome via unique structures during mitosis. What are these unique structures called?
The correct answer and explanation is:
The unique structures that spindle fibers attach to during mitosis are called kinetochores.
Kinetochores are protein complexes that form on the centromere of each chromosome during cell division. The centromere is a region of the chromosome where the two sister chromatids are held together, and the kinetochore is located at this site. The kinetochores are crucial for the proper alignment and separation of chromosomes during mitosis.
During prophase, the spindle fibers begin to form from microtubules, and the kinetochores attach to the spindle apparatus. The microtubules, also known as spindle fibers, extend from the centrosomes, which are specialized regions of the cell that organize microtubules. These spindle fibers then attach to the kinetochores of the chromosomes. The tension between the spindle fibers and the kinetochores helps align the chromosomes in the middle of the cell during metaphase.
In anaphase, the sister chromatids are pulled apart toward opposite poles of the cell. This separation is facilitated by the kinetochore’s interaction with the spindle fibers. The dynamic tension between the spindle fibers and kinetochores ensures that the chromatids are evenly divided, which is essential for maintaining the correct chromosome number in the daughter cells.
If the kinetochore does not function correctly, it can lead to errors in chromosome segregation, resulting in aneuploidy (an abnormal number of chromosomes), which is often associated with various genetic disorders, including cancer. Therefore, the role of the kinetochore is fundamental to the fidelity of cell division and maintaining genomic stability.