Answer
A nucleosome is the basic packing unit of chromatin in a eucaryotic nucleus. The central part of this unit is formed by eight isomers of histone proteins. Around this composite protein body is wrapped a double helical molecule of DNA, somewhat like thread around a spool. This DNA that wraps around the histone core is also called core DNA . There are also lengths of DNA between nucleosomes ; this is called linker DNA.
Work Step by Step
The proteins in the nucleosome core are usually designated histone proteins H2A, H2B, H3, and H4. There are two molecules of each of these. The length of DNA that is wrapped around the central octameric structure has been estimated to be about 146 base pairs(Bp) long. The linker DNA segment that ties nucleosomes together is shorter, probably about half that length.
