Three topics related to the effect of external forces and torques on the conformational kinetics of nucleic acids and nucleoprotein complexes are to be presented. First, we showcase the combination of molecular dynamics and free energy calculations on the topic of generating novel, "Pauling" DNA and RNA forms induced by external tensions and torques. Second, we show simulation evidence that the mechanisms for positive and negative DNA supercoil relaxation by human topoisomerase I are different.