Question

Choose the correct answer from the alternatives given:
histone proteins are
A- Basic , negatively charged
B- Basic, positively charged
C- Acidic, negatively charged
D- Acidic, positively charged

Answer 1

Hint: Between active and inactive states of chromatin histone protein plays an essential structural and functional role. The DNA replication is influenced by histone variant, post translational modifications and interactions with chromatin chromatin remodeling complexes .

Complete answer:
DNA organisation is complex in eukaryotes.In them a set of histone proteins occurs which are positively charged.Histone proteins are of five typesH1,H2A,H2B,H3and H4.Histone protein are rich in the asic amino acid residues lysine and arginine. Four of them the histone protein forms the core of the nucleosome. The positively charged octamer wrapped negatively charged DNA for the formation of nucleosomes. The two adjacent nucleosomes connected by DNA are called linker DNA which bears H1 histone protein.

Histones are a highly positively charged conserved protein. They interact electrostatically with the negatively charged phosphate group in DNA because of this positive charge.Core histone proteins are H2A, H2B,H3 and H4 while linker histones protein are H1 and H5.
Histone makes five types of interaction with DNA in all.
In the backbone of histone protein hydrogen bond forms between the DNA backbone and the peptide bond.
On DNA interaction between the DNA and deoxyribose sugar.

Hence, the correct answer is option (B)

Note: Histones are the basic protein that are associated with DNA in the nucleus and help it to condense into chromatin. At the point of interaction with negatively charged phosphate groups on DNA helix-dipoles form alpha- helices in H2B,H3 And H4.