Final answer:
In eukaryotic cells, DNA wraps around histone proteins to form nucleosomes, which are further compacted into chromatin and ultimately form chromosomes.
Step-by-step explanation:
In eukaryotic cells, DNA wraps around proteins known as histones to form structures called nucleosomes. The histones are evolutionary conserved proteins that are rich in basic amino acids and form an octamer composed of two molecules of each of four different histones. The DNA is wrapped tightly around the histone core. This nucleosome is linked to the next one with the help of a linker DNA. This is also known as the "beads on a string" structure. With the help of a fifth histone, a string of nucleosomes is further compacted into a 30-nm fiber, which is the diameter of the structure. Metaphase chromosomes are even further condensed by association with scaffolding proteins.