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The length of a DNA molecule in a typical mammalian cell is calculated to be approximately 2.2 metres. How is the packaging of this long molecule done to accommodate it within the nucleus of the cell? |
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Answer» Eukaryotic cells possess a set of positively charged, basic proteins called histones which are rich in basic amino acid residues lysine and arginine. Histones are organised to form a unit of eight molecules, called histone octamer. The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called nucleosome. A typical nucleosome contains 200 bp of DNA helix and nucleosomes form the repeating unit of a structure of the nucleus called chromatin. |
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