Nucleosomes: Structural Units of Chromatin

What are nucleosomes composed of?

Nucleosomes are structural units of chromatin, consisting of DNA wrapped around a core of histone proteins. Which histone proteins make up the core of the nucleosome?

Nucleosomes Composition

The core histones that make up the nucleosome include H2A, H2B, H3, and H4. These histones play a crucial role in organizing and compacting DNA within the cell nucleus.

Nucleosomes are fundamental units of chromatin structure, acting as a packaging mechanism for the long lengths of DNA in the cell. Each nucleosome consists of a segment of DNA wrapped around the histone core, forming a bead-like structure. The histone core is composed of the core histones H2A, H2B, H3, and H4.

These histones have a globular structure and assemble into an octamer core around which the DNA is coiled. This structure helps in organizing and condensing the genetic material within the nucleus, facilitating various cellular processes such as DNA replication, transcription, and repair.

While the core histones play a central role in nucleosome formation and chromatin organization, histone H1, also known as the linker histone, serves a different function. Histone H1 binds to the linker DNA regions between nucleosomes, stabilizing and compacting the chromatin fiber further.

Although histone H1 is involved in chromatin structure and gene regulation, it is not a component of the nucleosome core itself. The correct answer to the question is A) H1, as nucleosomes do not contain H1 within their core composition.