Histone

Definition

Histones are proteins that package and order DNA into structural units called nucleosomes. They play a crucial role in gene regulation by controlling access to DNA.

5 Must Know Facts For Your Next Test

1. Histones are positively charged, which helps them bind to the negatively charged DNA.
2. There are five main types of histones: H1, H2A, H2B, H3, and H4.
3. Histone modifications such as methylation or acetylation can influence gene expression by altering chromatin structure.
4. During DNA replication, histones need to be duplicated along with the DNA to maintain chromatin structure.
5. Histone proteins are highly conserved across different species, highlighting their essential role in cellular processes.

Review Questions

• What is the primary function of histones in relation to DNA?
• How do histone modifications affect gene regulation?
• Why is it important for histones to be replicated during DNA replication?

Related terms

Nucleosome:

A structural unit of a chromosome consisting of a length of DNA coiled around a core of histone proteins.

Chromatin:

The material that makes up chromosomes, consisting of DNA and associated proteins including histones.

Epigenetics:

The study of changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence, often involving histone modification.