Desoxyribonucleic acid
See DNA nanotechnology, MMathPhys oral presentation
https://en.wikipedia.org/wiki/DNA
Base pairing of Nucleobases via Hydrogen bonding
Can model DNA as a ribbon, and can define it's torsion. Boundaries of ribbon are the backbone, and they form the same surface that you get by twisting a normal ribbon.
Can also coarse-grain more, and model it as a curve.
Packing of DNA in a cell. See here
How DNA unties its own knots - Numberphile, using Type II topoisomerase (see more here). Drugs that target type II topoisomerase are used as antibiotics, because this enzyme is necessary for the cell to replicate correctly in bacteria. This is because the fact that DNA is a helix, and it forms a loop in bacteria means that when DNA is unzipped by helicase, the two single strand loops are interlinked. Topoisomerase then cuts and stiches DNA in such a way as to unlink them. See DNA replication
https://www.technologyreview.com/s/419590/quantum-entanglement-holds-dna-together-say-physicists/