This article describes the origins of aerobic respiration, the process in which oxygen is used as a fuel in living organisms. Evolutionary biologists Gustavo Caetano-Anolles of the University of Illinois and his colleagues in China and South Korea examined the genomes from all groups of organisms. Genomes are the entirety of an organism’s hereditary information; it is coded in either DNA or RNA. Using these genomes, they were able to distinguish domains, which are a part of a protein sequence and can evolve, function, and exist independently of the rest of the protein chain. These domains form a three dimensional structure which help in determining their functions. However, proteins with several domains often cause problems when determining the evolutionary origin of a domain. By focusing on domains which were involved in an aerobic metabolism, the biologists hoped to find the origin of this process. After creating a timeline for the evolutionary history of the domain associated with aerobic respiration, the researchers matched the sequence with a geologic timeline. The origin of a particular domain often corresponded to the appearance of a certain organism. The biologists discovered that about 2.9 million years ago, organisms which carried out aerobic processes emerged. They concluded that ancient archaea, single celled microorganisms, used aerobic respiration to produce a form of the vitamin B6. The oxygen necessary to create vitamin B6 came from the breakup of hydrogen peroxide. The scientists explained how the enzyme manganese catalase speeds up the decomposition reaction of hydrogen peroxide into water and oxygen. The scientists were able to support their argument with the fact that in this geological period, the massive amounts of hydrogen peroxide could have been produced by glaciers.
This article is significant because it helps scientists understand the origins of organisms which used oxygen as a primary source of energy. It is a major landmark in biology and other sciences since scientists were able to estimate a date when these organisms emerged. Further investigation could explain the development of the various oxygen using organisms.
This article was very informative, and it provided a clear explanation of the biologists’ process. However, there was a lot of scientific jargon in this article which would be hard for an average reader to understand. Despite the use of complex scientific terms, the article was able to deliver a comprehensive and clear explanation. I also liked how the article was able to prove the credibility of the scientists’ research, since it offered interpretations of the experiment from Paul Falkowski, a biogeochemist from Rutgers University, and biogeochemist Timothy Lyons, from the University of California.
Posted for A. Reddy
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