Each chromosome of a eukaryotic cell consists of a pair of identical structures called chromatids.

Here's a breakdown:

* Chromosomes: Long, thread-like structures found in the nucleus of eukaryotic cells. They carry genetic information in the form of genes.

* Chromatids: Two identical copies of a single chromosome that are joined together at a point called the centromere.

* Centromere: The constricted region of a chromosome that holds the two chromatids together.

During cell division (specifically, during mitosis and meiosis), the chromatids separate and each becomes a new chromosome, ensuring that each daughter cell receives a complete set of genetic information.