Question

Histones are tightly bound to DNA because:

• A. histones are positively charged proteins.
• B. histones are negatively charged proteins.
• C. histones get acetylated by the action of acyltransferases.
• D. histones are highly hydrophobic in nature.

Hint:

Opposites attract: Positive Histones + Negative DNA = Stable Nucleosome.

Answer 1

The Correct Option is A

Step 1: Concept
DNA packaging depends on the electrostatic attraction between DNA and histone proteins.

Step 2: Meaning
DNA is a negatively charged molecule due to the phosphate groups in its sugar-phosphate backbone.

Step 3: Analysis
Histones are rich in basic amino acids like lysine and arginine, which carry positive charges at physiological pH. This creates a strong electrostatic attraction that allows DNA to wrap tightly around the histone octamer.

Step 4: Conclusion
Therefore, the positive charge of histones is the primary reason they bind so tightly to the negatively charged DNA. Final Answer: (A)