Question

Nucleosome is:

• A. Positively charged DNA wrapped around negatively charged histone octamer
• B. Negatively charged DNA wrapped around positively charged histone octamer
• C. Positively charged DNA wrapped around positively charged histone octamer
• D. Negatively charged DNA wrapped around negatively charged histone octamer

Answer 1

The Correct Option is B

Nucleosomes are the fundamental subunits of chromatin, consisting of DNA and histone proteins. In a nucleosome, negatively charged DNA is wrapped around a positively charged histone octamer. This interaction is crucial because DNA has negatively charged phosphate groups, while histones, being proteins, have positively charged amino acids, which facilitate the binding of DNA around histone cores. 

Component	Description
DNA	Negatively charged
Histone Octamer	Positively charged

Hence, the correct conceptual understanding of a nucleosome is that it is composed of negatively charged DNA tightly wrapped around a positively charged histone octamer. This structural organization is vital for the compaction and regulation of DNA within the cell nucleus.

Answer 2

A nucleosome is the basic structural unit of chromatin, which is made up of DNA wrapped around histone proteins.

• DNA is negatively charged due to the phosphate groups in its backbone.
• Histone proteins are positively charged because they contain a high proportion of amino acids like lysine and arginine, which are positively charged.

The nucleosome is formed when the negatively charged DNA wraps around the positively charged histone octamer, which consists of eight histone proteins (H2A, H2B, H3, and H4 in pairs).