What is the primary feature of the structure of nucleosomes?

The primary feature of the structure of nucleosomes is that DNA is wound around histone proteins. Nucleosomes are the fundamental units of chromatin, which is the material that makes up chromosomes. Each nucleosome consists of a segment of DNA wrapped around a core of histone proteins, which helps to package the DNA tightly within the cell nucleus.

This winding of DNA around histones serves several important functions. It not only assists in the compact organization of DNA, making it fit into the limited space of the nucleus, but it also plays a crucial role in regulating gene expression. The way DNA interacts with histones can influence how available the DNA is for transcription, and therefore how genes are expressed.

In contrast, options discussing loose associations or tightly coiled DNA without proteins do not accurately describe the nucleosome structure, as they overlook the critical role histones play in organizing and compacting the DNA. The reference to DNA remaining in a single linear strand fails to encompass the elaborate packaging that occurs in nucleosomes, which is essential for maintaining the integrity and functionality of genetic material within the cell.