DNA double VVNlVvVk t2nm helix Figure 19.20 The 30 nm fiber may have a helical DNA double helix coil of 6 nucleosomes per tum,organized radially. “Beads-on 11 nm a-string Axis of coil form of chromatin 6.8:1 Nucleosome(10 nm fiber) Chromatin fiber of 30 nm packed nucleosomes 30 nm Fiber 40:1 Extended section of 300nm chromosome LoopsI 1000: Condensed section of chromosome 700nm Loops II 8000:1 Metaphase chromosome 1400nm chromosome 6.8:1 40:1 1000: 1 8000:1 DNA double helix Nucleosome (10 nm fiber) 30 nm Fiber Loops I Loops II chromosome