Final answer:
DNA wraps around histone proteins to form nucleosomes, coiling into a 30-nm chromatin fiber, and then further compacts to form visible chromosomes, particularly during cell division.
Explanation:
During cell division, double-stranded DNA wraps around histone proteins to form nucleosomes, resembling "beads on a string." These nucleosomes are coiled into a structure known as a 30-nm chromatin fiber, which condenses further to form visible chromosomes. The compaction process involves multiple levels—the DNA wraps around histone octamers to form nucleosomes, which are joined by linker DNA. Nucleosomes compact further into the 30-nm fiber, which then associates with scaffolding proteins during the metaphase stage of mitosis to achieve maximal condensation. This hierarchical structure allows the large eukaryotic DNA to fit within the cell nucleus, easing the process of segregation of chromosomes during cell division.