Histones are rich in:

The correct answer is Option (4) → Lysine and arginine

Histones are the proteins around which DNA is wound in a nucleosome. DNA is negatively charged. Histones are rich in basic amino acids, which carry a positive charge in their side chains, so they bind DNA firmly.

(1) Valine and methionine — Incorrect. Both have no charge on their side chains.

(2) Asparagine and phenylalanine — Incorrect. Both have no charge on their side chains.

(3) Leucine and alanine — Incorrect. Both have no charge on their side chains.

(4) Lysine and arginine — Correct. Both are basic and positively charged, so histones are rich in them.

Note: A similar question was also asked in CUET (UG) 2026 on 22-05-2026 (Slot 1), and in CUET (UG) 2025 on 22-05-2025 (Slot 2).

NCERT Extract:
Packaging of DNA Helix – “… In eukaryotes, this organisation is much more complex. There is a set of positively charged, basic proteins called histones. A protein acquires charge depending upon the abundance of amino acids residues with charged side chains. Histones are rich in the basic amino acid residues lysine and arginine.”