Question

What is a histone octamer?

Options

• A complex of eight non-histone chromosomal proteins

• The core component of prokaryotic nucleoids

• A group of eight different histone types found in eukaryotic nuclei

• A structural unit composed of eight histone protein molecules around which DNA is wrapped

Answer 1

A histone octamer consists of eight histone molecules—two copies each of H2A, H2B, H3, and H4. This octamer forms the structural core around which DNA wraps in 1.65 turns to form the basic repeating unit of chromatin, the nucleosome.