How is all of that DNA packaged so tightly into chromosomes and squeezed into a tiny nucleus? Long, slender DNA molecules wind around proteins and fold in complex ways to form chromosomes.

(A) Electron micrograph of a human cell section showing ... ubiquinone in green labeled with a Q; cytochrome c reductase in light blue; cytochrome c in dark blue labeled with cytC; cytochrome ...

(Courtesy: Sabrina Hopp/Angelika Stehle) The interaction between an electron and a calcium-40 nucleus has been calculated from first principles for the first time. Physicists in Germany and the US led ...