Final answer:
The core particle in nucleosomes consists of two molecules each of four different histones (H2A, H2B, H3, H4), making the statement TRUE. Nucleosomes enable the tight packing of DNA around these histone proteins, forming a bead-like structure on the DNA string.
Step-by-step explanation:
The statement that the core particle in nucleosomes is composed of two molecules each of histones is TRUE. Within the structure of a nucleosome, DNA is wrapped around a core of eight histone proteins, which includes two copies each of H2A, H2B, H3, and H4 histones.
This octameric arrangement allows about 146 base pairs of DNA to tightly coil around the histone proteins, making the nucleosome appear like a bead on a string when viewed through an electron microscope. The DNA in between these nucleosomes is called linker DNA and is associated with an additional histone, H1, which helps in compacting the DNA further.