A kinetochore is a protein structure that forms on the centromere of a chromosome during cell division. It serves as the attachment point for spindle fibers, which are essential for the movement of chromosomes. The kinetochore ensures that each daughter cell receives the correct number of chromosomes during mitosis and meiosis. During cell division, the kinetochore plays a crucial role in the alignment and separation of chromosomes. It helps to pull sister chromatids apart, guiding them to opposite poles of the cell. This process is vital for maintaining genetic stability and preventing disorders related to chromosome number, such as Down syndrome.