What's the tallest building in the city?
- The library because it's so many stories high!
DNA structureIn 1953, James Watson and Francis Crick submitted to the journal Nature their first article on the structure of DNA. It was published in the 25 Apr 1953 issue. "We wish to put forward a radically different structure for the salt of deoxyribose nucleic acid. This structure has two helical chains each coiled around the same axis... Both chains follow right-handed helices... The novel feature of the structure is the manner in which the two chains are held together by purine and pyrimidine bases... They are joined together in pairs, a single base from one chain being hydrogen-bonded to a single base from the other chain, so that the two lie side by side with identical z-co-ordinates. One of the pair must be a purine and the other a pyrimidine in order for bonding to occur."«[Image: DNA as illustrated in the Nature article.] |
