Question

What are nucleosomes?

Answer 1

Nucleosome:

1. A nucleosome contains DNA strands wrapped around the histone protein and forms the integral unit of chromatin.
2. It is a repeating unit that consists of 150 base pairs wrapped tightly around histones.
3. The histone part contains a set of eight proteins (H2A, H2B, H3, H4) referred to as the histone octamer.
4. The nucleosomes repeatedly fold and condense to form highly packaged DNA in the form of chromosomes.
5. The resultant structure is a 11 nm fiber commonly termed beads on a string.
6. The adjacent nucleosomes are interconnected via a linker DNA.
7. Structurally, nucleosomes appear as 'beads-on-string' in chromosomes when viewed under an electron microscope.