Biology 111 Application: Arsenic-based Life
“NASA will hold a news conference at 2pm EST on Thursday, December 2, 2010, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.”
That is how the press release from NASA started. As you can imagine, people began to speculate about alien life and whether NASA had really found something. The conference that day was, in fact, a little disappointing. NASA had no evidence of life on Mars. However, they did unveil a recently
published paper by researcher and scientist Felisa Wolfe-Simon. Fells is interested in questions like, “Why is phosphorus (in the form of phosphate) found in many biological molecules like DNA, RNA, ATP, and phospholipids?” Phosphorus is also used to tag proteins and change their activity (protein phosphorylation). This is a great question considering that there is very little phosphorus at the bottom of the ocean, where life is thought to have originated.
Looking at a periodic table, there are several atoms that maybe could have done the same job as phosphorus. Can you tell? Atoms in the same column often share similar characteristics. Arsenic is in the same column as phosphorus. The reason why arsenic is so poisonous to us in because it looks and acts like phosphorus to our cells. Felica’s published paper showed that there are cells that are able to use arsenic instead of phosphorus.
In her paper, Felisa claims to have found bacteria living in Mono Lake (CA) that are able to not only live in arsenic, but also take up arsenic and use it in important organic molecules. In her experiments, Felisa actually found that these bacteria were able to take up and incorporate both arsenic and phosphate, depending on what kind of growth medium they were exposed to.
NASA stated, “New NASA finding changes the fundamental knowledge about what comprises all known life on Earth.”
Two days after Felica’s paper was released, Rosie Redfield, a microbiologist at the University of British Columbia, posted a critique on her blog. Maybe these findings that NASA said would change the “fundamental knowledge” of life are inaccurate.
- In your opinion, why did the original paper by Felisa Wolfe-Simon get published?
- Please list the major organic compounds of life. What is DNA/genetic information made up of?
What main element makes up most of life? - What makes phosphorus so important to life (at least to life as we know so far)?
- Why were the findings of this original paper unique? If true, what could these findings mean?
- Look at the refutation papers that were published. What seems to be the major problem with the
original experiment?