In prophase of mitosis, specialized regions on centromeres called kinetochores attach chromosomes to spindle fibers. The centromere is the part of a chromosome that links sister chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. Kinetochores generate kinetochore fibers, which attach sister chromatids to spindle fibers. Kinetochore fibers and spindle polar fibers work together to manipulate and separate chromosomes during mitosis and meiosis.