Dna structure packaging of dna orderly so that chromosomes can replicate and be apportioned correctly between two daughter cells at each cell division. Must allow access to chromosomal dna for enzymes that repair when it is damaged, for specialized proteins that direct the expression of its genes. Dna (deoxyribonucleic acid) too long polynucleotide chains composed of four types of subunits hydrogen bonds between base portions of nucleotides hold chain together (base pairs) nucleotides five-carbon sugar attached to one or more phosphate group and nitrogen-containing base. G/c therefore each base pair has similar width backbones at equal distance apart along entire dna molecule. Most energetically favorable arrangement in dna interior. Dna linkers nucleosomes repeat at intervals of ~200 nucleotide pairs. Cmc and average number of detergent molecules in a micelle (also temperature, ph, and salt concentrations) properties of each detergent is a complex system.