Question

Name the positively charged & negatively charged components of the nucleosome.

Answer 1

Hint: Nucleosome is made up of two components namely, negatively charged DNA and positively charged histone proteins. In nucleosome, DNA is wrapped around a histone protein octamer and these oppositely charged particles combines to form a compact structure with the help of hydrogen bonding

Complete step by step answer: DNA is a large structure which has to be accommodated inside a small cell. In order to fit the large DNA inside the small cell, DNA gets packaged to form condensed structures. Nucleosomes are formed during the packaging of DNA. It consists of two opposite charged components where positively charged component is histone protein octamer and negatively charged component is DNA. Histone proteins are rich in the basic amino acid residues lysine and arginine. On the other hand, DNA is negatively charged because of phosphate ions present in phosphate backbone, this allows them to be closely associated with each other with the help of electrostatic interactions. A histone octamer comprises two units each of H2A, H2B, H3 and H4. H1- histone binds with the linker DNA between two nucleosomes. A typical nucleosome contains 200 bp of DNA helix. So, DNA and histone protein are the two main components of the nucleosome which are negatively charged and positively charged, respectively.

Note: A Nucleosome is a structural packaging unit of DNA found in eukaryotes, it is fundamental subunit of chromatin it has segments of DNA wrapped around eight histone proteins forming H- bond which is a dipole-dipole attraction between the molecules. Between the two nucleosomes lies the DNA segment which is known as linker DNA.