Final answer:
True, acetylation of histones changes their charge and promotes gene expression by loosening DNA-histone interactions, allowing transcription factors to access DNA.
Step-by-step explanation:
The statement is true: acetylation of the histones helps activate gene expression by changing the overall charges on the histone proteins. Histones are proteins around which DNA is tightly wound to form nucleosomes, which are the building blocks of chromatin. When unmodified, histones have a positive charge which allows them to bind tightly to the negatively charged DNA. Acetylation adds acetyl groups to the histones, which neutralizes some of the positive charges, resulting in a less tight association with DNA. This alteration leads to a looser packing of nucleosomes, making the underlying DNA more accessible for transcription machinery. Therefore, histone acetylation plays a critical role in regulating gene expression by making certain regions of DNA accessible so that transcription factors can bind and genes can be expressed.