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Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization
Chapter 10, Problem 1

Give descriptions for the following terms: nucleosome core particle

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1
The nucleosome core particle is the fundamental unit of chromatin structure in eukaryotic cells.
It consists of a segment of DNA wrapped around a histone protein octamer.
The histone octamer is composed of two copies each of four core histone proteins: H2A, H2B, H3, and H4.
Approximately 147 base pairs of DNA are wrapped around the histone octamer in about 1.65 turns.
This structure helps in the compaction of DNA and plays a crucial role in gene regulation and DNA accessibility.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleosome Structure

A nucleosome is the fundamental unit of chromatin, consisting of a segment of DNA wrapped around a core of histone proteins. This structure helps package DNA into a compact form, allowing it to fit within the nucleus of a cell. Each nucleosome core particle is made up of eight histone proteins, forming a histone octamer, around which approximately 147 base pairs of DNA are tightly wound.
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Chromosome Structure

Histones

Histones are highly alkaline proteins that play a crucial role in the organization and regulation of DNA within the cell nucleus. They help in the formation of nucleosomes by providing a scaffold for DNA wrapping. There are five main types of histones (H1, H2A, H2B, H3, and H4), with the core histones (H2A, H2B, H3, and H4) forming the nucleosome core, while H1 acts as a linker histone.
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Chromatin Packaging

Chromatin is the complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells. The packaging of DNA into nucleosomes and higher-order structures is essential for regulating gene expression and DNA replication. This organization allows for the efficient storage of genetic information and plays a key role in cellular processes such as transcription and DNA repair.
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