What term is used to refer to a structure composed of DNA and proteins that forms chromosomes?

The term "chromatin" refers to the complex of DNA and proteins that makes up chromosomes within the nucleus of eukaryotic cells. Chromatin plays a crucial role in packaging DNA into a more compact, dense shape, which is essential for proper chromosome segregation during cell division. It consists of DNA that is tightly coiled around histone proteins, allowing for the organization and regulation of genetic material.

While nucleosomes are the units that form chromatin and consist of a segment of DNA wrapped around a core of histone proteins, the broader term chromatin encompasses the entire assembly of DNA and proteins within the chromosome structure. Histones specifically are the proteins that help in the organization of DNA, but they do not represent the full structure of DNA and proteins together. A gene, on the other hand, is a unit of heredity that is made up of DNA and encodes information for making proteins but does not indicate the overall structure formed by DNA and proteins. Thus, the term that best describes the complete structure is chromatin.