Final answer:
Histone proteins form the core nucleosome, which includes tetramers of histone H2A, H2B, H3, and H4. This structure is known as the "beads on a string". The nucleosomes are further compacted into a 30 nm fiber.
Step-by-step explanation:
The histone proteins that constitute the core nucleosome include tetramers of histone H2A, H2B, H3, and H4. This is also known as the "beads on a string" structure. The negatively charged DNA is tightly wrapped around the histone core, and the nucleosomes are further compacted into a 30 nm fiber. At the metaphase stage, the chromosomes are highly compact and found in association with scaffold proteins.