Practice question

Chromatin represents the physiological form of eukaryotic genome inside nucleus, a highly organized nucleoprotein complex rather than naked DNA. Biochemical fractionation shows roughly equal masses of DNA and protein. Major proteins include core histones forming octamers that spool 147 base pairs into nucleosomes, linker histone H1 sealing entry exit DNA, plus nonhistone scaffold proteins like topoisomerase II and condensin. Electrostatic neutralization between basic histone tails and acidic phosphate backbone compacts length thousand fold and regulates accessibility for transcription, replication and repair machineries.