Answer – A centromere is the constricted point at which the two sister chromatids are joined and which divides the chromosome into a long arm and short arm.
Explanation:
DNA, or genetic information, for each cell is carried on the chromosomes within the cell’s nucleus. During interphase, when the cell is not dividing, the chromosomes assume a fine, thread-like form. However, when cell division begins, these threads condense into a thicker cylindrical structure, which is pinched at a point that divides it asymmetrically. This point of constriction is the centromere.
A centromere is the constricted point at which the two sister chromatids are joined Image Credit: Christinelmiller / Wikimedia Commons (licensed under CC BY-SA 4.0)
When the chromosome replicates, the two resulting sister chromatids are attached to each other at the centromere. It is also the site of a protein assembly called kinetochore. It ensures that each sister chromatid contains all the information of the chromosome, and that they are exact copies of one another.
As the larger cell structure divides, the pairs of sister chromatids are aligned along their centromeres, and each pair is encased in spindle fibers attached to the centromere. This provides a space for the sister chromatids to detach from each other, as each goes to one of the two daughter cells.
