Nucleosomes : Basic Unit of Eukaryotic Chromosome Structure

07.06 0 Comments

The proteins that bind to the DNA to form eukaryotic chromosomes are traditionally divided into two classes: the histones and the non-histone chromosomal proteins, each contributing about the same mass to a chromosome as the DNA. The complex of both classes of protein with the nuclear DNA of eukaryotic cells is known as chromatin


Nucleosomes as seen in the electron microscope

(A) Chromatin
isolated directly from an interphase nucleus appears in the electron microscope as a thread about 30 nm thick

(B) This electron micrograph shows a length of chromatin that has been experimentally unpacked, or decondensed, after isolation to show the nucleosomes.