Extra Credit

This extra credit opportunity is untimed, and you may come back to it any time prior to the due date. You may answer the questions any time prior to Friday, December 18, 2020 at 11:59 p.m. E.T.

Question Prompt: In 2010, a study was published suggesting that a bacterium could be using arsenic instead of phosphorus in building its DNA and other molecules. This would be unique as arsenic is thought to be toxic to life forms. Recently, many other studies have been released refuting the original claim. This is how science works:

• Observations are made – life exists in waters with high levels of arsenic and other toxic elements.
• Hypotheses are created – If bacteria do not have phosphorus but are exposed to arsenic, will the arsenic be taken up and used? Arsenic is in the same periodic table group as phosphorus so perhaps the similar chemical characteristics will work.
• Testing the hypothesis – controlled experiments are devised to test the ideas. Controls in the procedure ensure that the only change occurring would be due to the change of only one variable, in this case the amount of phosphorus available to the bacteria.
• Analysis of results – strict rules about how the data are treated so that little or no bias can enter into the analysis. One way of doing this is with a double blind study which means that neither party analyzing the data knows the exact content of the samples but return their reports to those who have marked the samples.
• Peer review and publishing – the traditional method involves having other scientists in the field review the work and critique the protocols and how the data were analyzed. Scientific journals such as Nature, Science, The Lancet among others are recognized for their peer review process to publish scientific studies.

Your assignment: Search the online literature for at least two (2) articles relating to the initial publication and the fallout from the studies refuting the original story’s claim. Be sure to cite these sources in your submission. Use the sources to answer the following 2 questions.