Introduction to Life Science: Nature and Structure of DNA

Introduction to Life Science
Name
Institution
Introduction to Life Science
The chemical nature and structure of DNA were not understood until mid-twentieth century. Before this time, scientists spent many years trying to understand which of the numerous types of molecules within cells comprised the hereditary material. Questions arose of whether it was protein, or even another molecule that had not yet been discovered. Ultimately, multiple experiments and scientists are responsible for the discovery of DNA hereditary material and structure (Portin, 2014).
One major experiment that contributed in the discovery of DNA as hereditary material was done in 1869 by a Swiss chemist known as Friedrich Miescher. Miescher was studying white blood cells when he isolated a molecule that was unknown before. The molecule was somewhat acidic and comprised of a high percentage of phosphorus. He named this molecule “nuclein” and this was later on changed to “nucleic acid” and finally to “deoxyribonucleic acid” or DNA (Portin, 2014). Surprisingly, Miescher had no idea that nuclein was the carrier of the hereditary material because he believed it did not have the variability essential to explain the diversity of organisms. In this way, like most scientists at the time, he believed that proteins carried the hereditary information (Gьз, 2004).
For several decades after Miescher’s discovery, scientists still felt that protein was the carrier of the hereditary material. However, in 1944, a biologist named Oswald Avery made a discovery while experimenting with the bacterial responsible for pneumonia. During this time, scientists believed that some types of bacteria (S type) contained an outer layer known as capsule, but other types (R type) did not have this layer. Avery and his colleagues found out that only DNA can change the R type bacteria into the S type. This discovery meant that DNA was not too simple as thought by many scientists because it allowed carrying of instructions from one cell to another. The result of the experiment meant that DNA was the ...