Practice question

Chromosome morphometry quantifies hierarchical folding ratios. Starting from 2 nanometer DNA helix, beads-on-string 11 nanometer, 30 nanometer helix, 300 nanometer looped domain scaffold attached, finally fully condensed metaphase chromatid about 700 nanometer wide, complete metaphase chromosome with two sister chromatids about 1400 nanometer or 1.4 micrometer diameter. Dimensions illustrate approximately ten thousand-fold linear compaction enabling 2 meters human diploid DNA fit nucleus. Electron microscopy of isolated metaphase chromosomes shows width near 1400 nanometer. Values 300 nanometer refer to loop scaffold, 700 single chromatid, 30 nanometer intermediate fiber, 2 nanometer naked DNA.