nucleosome

compact spool tight acetylation unit cellular activation life eight lecture phenotype expression wrap physiological peptide polypeptide mutation laboratory histones nucleolus methyl chemistry suppress biochemistry macromolecule deoxyribonucleic chromosomes dna molecule biological microscopic anatomy scientific h1 h3 cell h4 genetics h2a h2b nucleus biotechnology epigenetic pack methylation nucleotide tail microbiology regulation infographic education genome diagram structure chromatin evolution medicine health spiral chromosome genetic human molecular histone nucleosome science sequence double gene biology model protein helix medical proteins vector research