Why do histones bind tightly to DNA?

• A. Because histones are hydrophobic and DNA is hydrophilic.
• B. Because histones are composed of RNA, which naturally binds to DNA.
• C. Because histones are positively charged and DNA is negatively charged.
• D. Because histones are enzymes that catalyze DNA replication.

Answer: (C)

Verified step by step guidance

1. Understand the structure of DNA: DNA is composed of nucleotides, each containing a phosphate group, which gives DNA a negative charge.
2. Learn about histones: Histones are proteins that help package DNA into structural units called nucleosomes. They are rich in basic amino acids like lysine and arginine.
3. Recognize the charge properties: Basic amino acids in histones carry a positive charge due to their side chains.
4. Apply the concept of charge attraction: Opposite charges attract, so the positively charged histones bind tightly to the negatively charged DNA.
5. Conclude the reason for binding: The electrostatic attraction between the positive charges on histones and the negative charges on DNA is the primary reason for their tight binding.