DNA: The Master Code for All Living Things

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Bacteria, zebras, mosquitoes, anacondas, essentially all living things have one thing in common which makes them what they are. It is DNA. It is one of the greatest biological discoveries in the history of mankind. It is not only related to biology but is tied to the study of chemistry as well because of the convoluted molecular structure. DNA is short for the molecule deoxyribonucleic acid. RNA or ribonucleic acid is another nucleic acid derived from DNA and used as a template to make proteins, the product of the genetic code. In an article, “What is DNA?” written by James Randerson, DNA is described as, “...the master code for life ... the instruction book that each organism uses to run its body and govern its behavior, a book that each creature hands on to its offspring, either in full or in part.” In other words it describes how at times not the whole book (DNA) is passed down from parent to progeny. A father and mother both contribute their DNA making the son similar but not identical to his father and mother. Also, because DNA stores all genetic information including diseases, which can be passed down from generation to generation. These diseases are the effect of a mutation in the DNA structure.

In 1868, a Swiss physician and biologist extracted a phosphorus containing substance. He called it nuclein because he found it in the nuclei of several cells. He managed to extract this substance from discarded surgical bandages, specifically by examining the pus cells (pus cells are white blood cells). James Watson, an American geneticist, and Francis Crick, a British physicist studying in the University of Cambridge, began examining x-ray images made by Rosalind Franklin and Maurice Wilkins. In 1953, James and Francis constructed the first three-dimensional model of the DNA structure. The model showed all nitrogenous bases, pentoses (sugar), and phosphate groups. Several years later, James Watson, Francis Crick, and Maurice Wilkins received the Nobel Prize for Physiology or Medicine. Before the three-dimensional model, Erwin Chargaff discovered a pattern between the base pairs. He discovered that the amount of adenine is the same amount of thymine. the same is true for the other base pair guanine and cytosine. Chargaff’s discovery led him to understand the basic pairing rules. You might wonder what makes our DNA different from the DNA of a sheep, sea urchin, or a turtle. Based on the studies of Chargaff and the rest of his colleagues at Columbia University, the four nitrogenous bases occur in different ratios in the DNAs of different organisms and that the bases have a numerical relationship. For example, The base composition (mol percentage) of Homo Sapiens is 30.9 % adenine, 19.9% guanine, 19.8% cytosine, and 29.4% thymine. This shows that Chargaff’s study was very helpful for James Watson and Francis Crick’s three-dimensional model of a DNA molecule.

I chose to research DNA because it is a very interesting topic to discuss. It makes me who I am, my hair, eye, and skin color, my height and weight, overall health, metabolism, etc. I find both biology and chemistry my favorite subjects and DNA because it is a key molecuel that defines health. In the future I plan to become a M.D. (Medical Doctor). I will definitely have to be familiar with this molecule and what DNA sequences mean in case I needed to diagnose a patient with a certain genetic disease. By examining his or her genetic code I could determine possible diseases. I really enjoy any type of problem solving. I could utilize this knowledge to explore disease in my own family, specifically my dad’s side. From my grandfather to my own father and uncles, everyone has minor cardiovascular diseases caused by high cholesterol. I want to discover what mutation in my family’s DNA that causes this condition and develop treatments to improve their health.

DNA molecules are located in the nucleus of a cell. When they are tightly packed together they are known as...
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