Which statement about histone acetylation is true?

• A. It generally decreases transcription by condensing chromatin.
• B. It generally increases transcription by opening chromatin.
• C. It has no impact on transcription.
• D. It changes the amino acid sequence.

Answer: (B)

Histone acetylation changes chromatin structure to regulate transcription. Adding acetyl groups to lysine residues on histone tails neutralizes their positive charge, loosening the interaction between histones and DNA. This leads to a more open chromatin state (euchromatin) that makes promoter and regulatory regions accessible to transcription machinery, generally increasing transcription. It’s a post-translational modification of histone proteins, not a mutation that changes the DNA sequence or the amino acid sequence of genes.