NASA Writing Assignment
The six main elements of life are carbon, hydrogen, oxygen, nitrogen, phosphorous, and sulfur. (NASA) According to biologist, life cannot exist without all six elements. Biologist were suddenly confused when NASA released a study in December of 2010. It was the discovery of a microorganism that could sustain life with close to no phosphorous. This unique microorganism’s name is GFJ-1 and is from the Halomonadaceae family. What sets apart GFAJ-1 is its ability to make cellular components out of arsenic instead of phosphorous. Phosphorous is a key component of the energy carrying molecule ATP. It also helps to keep the structure of DNA, transfer energy within the cell, and make cell membranes. The main difference is arsenic is more reactive than phosphorous. Arsenic can travel through the same channels as phosphorous, meaning that arsenic usually will destroy and breakup the chemical makeup or the DNA. On the other hand, arsenic is somehow capable of building its DNA with arsenic rather than harmed by it.
DNA is shaped physically similar to a spiral. DNA is made up of the rungs which hold the genetic code for life and the backbone which refers to the sides of the spirals ladder. The backbone consists of phosphate and sugar molecules. In order to have a phosphate molecule, it must have a phosphorous atom and four oxygen atoms. The significance of this is if there is no phosphorous then there is no phosphate. “If there is no phosphate then there is no backbone, without a backbone there is no DNA, with no DNA there is no life” (Bortman).
Is GFAJ-1 really able to substitute arsenic for phosphorous? Or is there a small amount of phosphorous still present which allows the growth to occur? One compelling piece of information that supports Wolfe’s study is that when “GFAJ-1 is grown in an environment that lacks both arsenic and phosphorus its cells do not grow. This damages the argument that the trace phosphorus in the supposedly "phosphorus free" conditions is enough to sustain GFAJ-1” (Singal). Steven A. Benner, a chemist questions arsenates ability to thoroughly replace phosphate. He believes arsenic is spread throughout the cells somewhere; that arsenic is present in small amounts. Other scientists also question the study and Wolfe-Simons validity. In order to prove that GFAJ-1 was capable of surviving only on arsenic, “the bacterium was grown in an environment that was high in arsenic but lacked phosphorus” (singal). “As a control, a second culture of GFAJ-1 cells was fed phosphorus instead of arsenic. They, too, grew and divided. GFAJ-1 seems able to switch back and forth, depending on how much phosphorus is available” (Bortman). In conclusion, “every experiment Wolfe-Simon performed pointed to the same conclusion: GFAJ-1 can substitute arsenic for phosphorus in its DNA. I really have no idea what another explanation would be,” Wolfe-Simon says (Bortman).
NASA’s Wolfe-Simon, NASA microbial biologist, discovered...