Bio Chemistry Gallery

Watson and Crick, DNA discovers

Watson and Crick. Caricature of the molecular biologists and discoverers of the structure of DNA James Watson (born 1928, left) and Francis Crick (1916-2004), with their model of a DNA molecule. Watson, an American, and Crick, British, met at the Cavendish Laboratory, Cambridge, in 1951. Their work on DNA was performed with a knowledge of Chargaff's ratios of the bases in DNA and access to the X-ray crystallography of Maurice Wilkins and Rosalind Franklin at King's College London. Combining this knowledge led to the deduction that DNA exists as a double helix. Crick, Watson and Wilkins shared the 1962 Nobel Prize for Physiology or Medicine, Franklin having died in 1958

© GARY BROWN/SCIENCE PHOTO LIBRARY

HIV reverse transcription enzyme

HIV reverse transcription enzyme. Molecular models of the reverse transcriptase enzyme found in HIV (the human immunodeficiency virus). The foreground model shows the helices and arrowed sheets representing the enzyme's shape (secondary structure). The background model shows the 7844 atoms (spheres) of the molecular structure. Reverse transcriptase is an enzyme that is a key part of the process of producing DNA (deoxyribonucleic acid) from the instructions contained in a strand of RNA (ribonucleic acid). Many viruses, including HIV, consist of a core of RNA, and this reverse transcription is how HIV infects human cells. This enzyme is from the HIV-1 form of HIV, the virus that causes AIDS (acquired immune deficiency syndrome)

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY

DNA Double Helix with Autoradiograph

Conceptual computer illustration of the DNA double helix together with a graphic representation of an autoradiograph display. The pattern of the DNA autoradiograph bands is unique to each individual, but some bands are shared by related people, such as a parent & child. DNA fingerprints can be used to prove conclusively whether people are related. The double-helix model of DNA structure was first published in the journal Nature by James D. Watson and Francis Crick in 1953, based upon the crucial X-ray diffraction image of DNA labeled as "Photo 51", from Rosalind Franklin in 1952. The structure of a double-helix elucidated the mechanism of base pairing by which genetic information is stored and copied in living organisms. Genetic fingerprinting and DNA profiling was developed by Dr. Alec Jeffreys and his team in 1985

© DAVID PARKER/SCIENCE PHOTO LIBRARY