Chromatid is a term used for one of two identical halves of chromosomes that have been replicated in preparation for cell division. Two sister chromatids are joined together at a specific region of the chromosome called the centromere. During cell division, each sister chromatid is pulled to the opposite side by the spindle fiber, which is attached to the centromere. And when the cells divide into two, it makes daughter cells with identical DNA. This cell replication is very important during growth and for replacing the cells which got damaged. For example, the cut heals when a person gets a cut on his skin. It is because of cell replication that the new cells are exact copies of the old ones. The chromosomes also contain copies in the form of chromatids which contain special structures for separating daughter cells.