What term refers to one of the two identical halves of a duplicated chromosome?

The term that refers to one of the two identical halves of a duplicated chromosome is chromatid. When a chromosome is duplicated during the cell cycle, particularly in the S phase, each replicated chromosome consists of two identical strands, known as sister chromatids. These chromatids are joined together at a region called the centromere. When cell division occurs, specifically during mitosis or meiosis, the chromatids separate and are distributed to the daughter cells, ensuring that each new cell receives an identical set of genetic material.

Chromatin, while related, refers to the complex of DNA and proteins found in the nucleus of eukaryotic cells, and it exists in a less condensed form than chromosomes. A gene is a specific sequence of DNA that encodes instructions to make proteins and is not synonymous with the structure of a chromatid. The centromere is merely the point of constriction that connects the two chromatids and does not refer to the chromatids themselves. Thus, identifying chromatids as the correct term clarifies their role in chromosome structure and function during cell division.