Question

I need an essay about 300 words for this topic : DNA Secret of Photo 51

Answer 1

DNA: secret of Photo 51

In the early 1950s biologists were searching for the answers to some of the most important science questions left unanswered. How is information stored inside living cells? How did it work? Etc..etc..All of these questions were an important part of biology and many scientists were racing to find the answers.

On April 25, 1953, the science journal Nature announced that James Watson and Francis Crick had discovered the double helix structure of DNA, the molecule that is fundamental to life. But absent from most accounts of their Nobel Prize-winning work is the contribution made by a scientist—molecular biologist and crystallographer Rosalind Franklin.

Photo 51 is an X-ray diffraction image of a paracristalline gel composed of DNA fiber. The image was tagged "photo 51" because it was the 51st diffraction photograph that Franklin and Gosling had taken. It was critical evidence in identifying the structure of DNA. While a lot of Rosalind Franklin's work used X-ray crystallography she also used other X-ray diffraction techniques. Photo 51 was made using a X-ray technique that did not require the sample to be in crystal form .Crystals are solids with regular, repeating units of atoms. She used this method since DNA, like some other macromolecules, does not like to form a crystal. Instead, DNA prefers to form organized fibers. Photo 51 still shows the classic diffraction pattern, but in this case the sample still contained water and was not a crystal, and that is why the resulting X-ray diffraction pattern of DNA was of a higher quality than any patterns collected prior.

James Watson was shown the photo by his collaborator, Maurice Wilkins, without Rosalind Franklin's knowledge. Along with Francis Crick, Watson used characteristics and features of Photo 51, together with evidence from multiple other sources, to develop the chemical model of the DNA molecule. The diffraction pattern determined the helical nature of the double helix strands (antiparallel). Watson and Crick's calculations from Gosling and Franklin's photography gave crucial parameters for the size and structure of the helix.

However, Watson, Crick, and Wilkins received the 1962 Nobel Prize in Physiology or Medicine. The prize was not awarded to Franklin; she had died four years earlier, and although there was not yet a rule against posthumous awards, the Nobel Committee generally does not make posthumous nominations.

Though Franklin was not awarded the Nobel Prize, the world cannot deny the fact that she was a brilliant scientist.