chromatin

biology

Also known as: chromatin fibre

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June 24, 2026

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Chromatin is a complex of DNA and proteins, primarily histones, found within the nucleus of eukaryotic cells. This intricate structure allows the cell's long DNA molecules to be efficiently packaged and organized.12

The basic unit of chromatin is the nucleosome, formed when DNA wraps around a core of histone proteins. These nucleosomes are then further coiled and folded into a compact fiber. This packaging is crucial for fitting the vast amount of genetic material into the nucleus and plays a vital role in regulating gene expression, DNA repair, and cell division. When a cell divides, chromatin condenses further to form visible chromosomes.3412

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cell
DNA packaging
…a dense, compact fiber called chromatin. An extreme example of the ordered folding and compaction that chromatin can undergo is seen during cell division, when the chromatin of each chromosome condenses and is divided between two daughter cells (see below Cell division and growth).
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…a dense, compact fiber called chromatin. An extreme example of the ordered folding and compaction that chromatin can undergo is seen during cell division, when the chromatin of each chromosome condenses and is divided between two daughter cells (see below Cell division and growth).
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cell
The differentiated state
…exists in the form of chromatin, which is made up of DNA bound to histones (simple alkaline proteins) and other nonhistone proteins. Most of the DNA is complexed into repeating structures called nucleosomes, each of which contains eight molecules of histone. Active genes are found in parts of the DNA…
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…exists in the form of chromatin, which is made up of DNA bound to histones (simple alkaline proteins) and other nonhistone proteins. Most of the DNA is complexed into repeating structures called nucleosomes, each of which contains eight molecules of histone. Active genes are found in parts of the DNA…
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histone
…a compact structure known as chromatin. A so-called linker histone, H1, binds to linker DNA, located where the strand enters and exits the nucleosome, and thereby adds stability to the chromatin structure.
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…a compact structure known as chromatin. A so-called linker histone, H1, binds to linker DNA, located where the strand enters and exits the nucleosome, and thereby adds stability to the chromatin structure.
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