Definition
noun, plural: histones
A water-soluble alkaline protein in the nucleus, and from where the DNA tightly coils around to form the nucleosome
Supplement
Histone is a water-soluble alkaline protein. It is rich in lysine and arginine. There are five major families of histones: H1, H2A, H2B, H3, and H4. The first is a linker whereas the other four are core.
Histones are the proteins in the nucleus serving as spools from where the DNA tightly coils around at. Histones form a core by which the DNA wounds around to form the fundamental structural unit of chromatin, the nucleosome. A nucleosome is made up of around 200 base pairs and eight histones (i.e. histone octamer). These histones include two of each of H2A, H2B, H3 and H4. The histone octamer through which DNA coils around facilitates the packing of a large genome into the nucleus. Without the histone core the genome would be too lengthy to fit into the nucleus. The length of the DNA in a human diploid cell is about 1.8 meters whereas the nucleus has about a diameter of 10 µm. Apart from compacting DNA strands, the histones are also associated with chromatin regulation. They undergo modifications for several biological processes, e.g. DNA repair, spermatogenesis in meiosis, and chromosome condensation during mitosis.
See also:
Dictionary > Histone
You will also like...
![Still Water Animals](https://www.biologyonline.com/wp-content/uploads/2020/02/Still-Water-Animals-252x168.jpg)
Still Water Animals
Animals living in aquatic habitats have diversified and evolved through time. They eventually occupy ecological niches a..
![Chemical composition of the body](https://www.biologyonline.com/wp-content/uploads/2020/02/Chemical-composition-of-the-body-300x168.jpg)
Chemical Composition of the Body
The body is comprised of different elements with hydrogen, oxygen, carbon, and nitrogen as the major four. This tutorial..
![sponge](https://www.biologyonline.com/wp-content/uploads/2020/02/Primitive-Animals-252x168.jpg)
Primitive Animals
Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like or..
![complete-dominance](https://www.biologyonline.com/wp-content/uploads/2019/10/complete-dominance-300x168.jpg)
Dominance
This tutorial presents Gregor Mendel's law of dominance. Learn more about this form of inheritance and how it can be pre..
![DNA - schematic](https://www.biologyonline.com/wp-content/uploads/2020/07/DNA-300x168.jpg)
Genetic Mutations
This tutorial looks at the mutation at the gene level and the harm it may bring. Learn about single nucleotide polymorph..
![Bryophytes](https://www.biologyonline.com/wp-content/uploads/2020/02/Bryophytes-252x168.jpg)
Bryophytes
Bryophytes (nonvascular plants) are a plant group characterized by lacking vascular tissues. They include the mosses, th..