Question

What is the fundamental structural unit of chromatin in which DNA is wrapped around a histone octamer consisting of H2A, H2B, H3, and H4, often described as "beads on a string," and where does histone H1 fit into this structure?

Answer 1

The fundamental structural unit of chromatin is a nucleosome, which consists of DNA wrapped around a histone octamer. Histone H1 binds to the linker DNA between nucleosomes.

Step-by-step explanation:

The fundamental structural unit of chromatin in which DNA is wrapped around a histone octamer consisting of H2A, H2B, H3, and H4 is called a nucleosome.

The nucleosome is often described as 'beads on a string' because when multiple nucleosomes are connected by linker DNA, they resemble a string of beads.

Histone H1 fits into this structure by binding to the linker DNA that connects the nucleosomes, helping to further stabilize the chromatin structure and compact it into a 30-nm fiber.