centromere, structure in a chromosome that holds together the two chromatids (the daughter strands of a replicated chromosome). The centromere is the point of attachment of the kinetochore, a structure to which the microtubules of the mitotic spindle become anchored. The spindle is the structure that pulls the chromatids to opposite ends of the cell during the cell division processes of mitosis and meiosis. Once separated, each chromatid becomes a chromosome. Thus, when the cell divides, both daughter cells have complete sets of chromosomes.