Scientists and Their Discoveries.

Scientists and Their Discovery

I have decided to research on three scientists that have made a huge mark on science and people today. They discovered something amazing together which helps us in so many ways, not only in our studies for biology, but for our normal day to day lives as well. These scientists’ names are James Watson, Rosalind Franklin and Francis Crick.

On Feb. 28, 1953, Francis Crick walked into a pub called Eagle in Cambridge, England, and said that "we had found the secret of life." And they had. That morning, Watson and Crick had figured out the structure of deoxyribonucleic acid, DNA. And that structure — has been called the "double helix". The British Crick, at 35, still had no Ph.D. The American Watson, 12 years Crick's junior, graduated from the University of Chicago at 19 and received his doctorate at the age of 22. Crick had migrated from physics into chemistry and biology and Watson had studied ornithology, and then doing postdoctoral work in Europe, took another career change. In King's College in London, there was a woman named Rosalind Franklin that was creating the world's best X-ray diffraction photos of the DNA. Of the four DNA researchers only she had university degrees in chemistry. She died of cancer in 1958, at the age of 37. In 1962 the Nobel Prize, was given to Watson, Crick and Wilkins. Crick said, if Franklin had lived, "It would have been impossible to give the prize to Maurice and not to her" because "she did the key experimental work." Maurice Wilkins plays a small part in this discovery. He and Rosalind did not get on very well and this probably slowed down their process.

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With a lot of work time and partnership, these scientists discovered the structure of DNA. DNA stands for Deoxyribonucleic acid. It is made up of nucleic acids that contain deoxyribose (sugar), that consist of complex molecules, that are in the chromosomes that all plant and animal cells have, and carrying in coded form instructions for passing on hereditary characteristics.
The DNA molecule is in the shape of a double helix. This double helix is a simple structure that looks like gently twisted ladders. The rails of the ladder are made up of pairs of nitrogen-containing nucleotides that are subdivisions of DNA. If you understand the structure of a molecule you would have some idea about how it functions. Because each nucleotide within a rung of the DNA ladder is always paired with the same complimentary nucleotide, one half of the molecule can be a template for the construction of the other half of the molecule. The four nucleotides in DNA are the bases called adenine (A), guanine (G), cytosine (C) and thymine (T). In nature, base pairs form only between A and T and between G and C, but the base sequence of each single strand can be taken from its partner. This pairing tells us how identical copies of parental DNA can be passed on to two daughter cells. During the cell division, the double helix “unzips”, and then two brand new molecules are created from the half-ladder templates.

In 1951, Watson went to a lecture by Franklin. She discovered that DNA can exist in two forms. This depends on the relative humidity in the surrounding air. This helped Rosalind decide that the phosphate part of the molecule was on the outside. Watson came back to Cambridge with a blurry collection of information of the facts that Franklin had talked about. Based on this information, Watson and Crick created a wrong model of the DNA. This made the head of their unit to tell them to stop the DNA research. But the DNA interest just kept coming up and getting them even more interested.

Franklin mostly worked alone and she found that her x-ray diffractions showed that the "wet" form of DNA (in higher humidity) had all the characteristics of a helix. She suspected that all DNA was helical but didn’t want to tell anyone about her discovery until she had completely correct evidence on the other form as well. Wilkins was very frustrated at this time. In January, 1953, he presented Franklin's results to Watson, but without her knowledge or permission at all. Crick later admitted, "I'm afraid we always used to adopt -- let's say a patronizing attitude towards her."

Watson and Crick suggested that the molecule was made of two chains of nucleotides, each in a helix as Franklin had found, but one going up and the then other going down. Crick had just learned of Chargaff's findings about base pairs. This was in the summer of 1952. Crick added this to the model, so that matching base pairs interlocked in the middle of the double helix to maintain the distance in between the chains constant.

Watson and Crick showed that each strand of the DNA molecule was a template for the other. During cell division the two strands go and separate and on each strand a new "other half" is made, just like the one before. Because of this, DNA can reproduce itself without changing its structure (except for occasional errors or mistakes).

The structure that they had made fit the experimental data so perfectly that it was almost immediately accepted. DNA's discovery has been called the most important biological work of the last 100 years, and the opportunities it opened may be the scientific frontier for the next 100. It is absolutely amazing how many these scientists discovery has made a contribution to the many important discoveries and uses today-in our world. DNA is being used almost everywhere. It is used to locate/identify biological parents, war victims, crime victims, etc. it is also used a lot in the CIA and the FBI, since it can contribute a lot to a certain investigation. This is either to find the criminal or to identify who the criminal is. And another very important contribution is in healthcare. Many diseases are observed and discovered through the DNA. This way the doctors can help and maybe cure the sicknesses that have never been even identified before. These scientists’ discovery became a new scientific discipline called molecular biology.