Sunday, April 5, 2015

"Organic" Molecules and Life in the Universe

I have been working on a side-project at NASA trying to create a statistical potential or chemical model that would allow one to distinguish whether a molecule was generated by biotic(living) processes or abiotic(non-living) processes. From my research I have become a somewhat amateur chemist of the universe which has significantly upped my status as a mere chemist of biotic processes(biochemist) on the Pale Blue Dot.

Did you know that amino acids are formed by abiotic processes?

I have always looked at data that meteorites contain amino acids with skepticism, as one should with all Science, especially when it is a little outside the norm or extra-ordinary.

Now that I have learned about it and thought about it, not only is the data solid, the processes make sense and it all starts with the chemical composition of the universe.

The universe is composed primarily of Hydrogen, Oxygen, Carbon, Nitrogen and Helium (yeah the Helium is very interesting! Maybe a blog post on that another time). It is no wonder that organic life on Earth is composed of molecules that contain primarily Hydrogen, Oxygen, Carbon and Nitrogen.

Amino acids are simple molecules composed of these elements

Now if we start to think about what molecules are abundant in the universe we find things like Carbon Monoxide(CO), Methane (CH3) Ammonia (NH3), Hydrogen Cyanide (HCN) and Formaldehyde (H2CO)!

Using mixtures of these Methane, Ammonia and Water Scientists have been able to synthesize some amino acids through applying electrical discharges.

But that's not all, reactions that create amino acids are not uncommon. The reaction of Ammonia with Formaldehyde has a name, The Mannich Reaction

The final product of the Mannich Reaction looks remarkably similar to the Amino Acid, no? It actually is Glycine!

There have been a number of studies to detect interstellar glycine, the simplest amino acid, but so far the results are inconclusive. Scientists think they might have detected it but others want suggest more robust measurements first.

So what does this say about life on Earth and perhaps elsewhere? Was the first "life" an Amino Acid World and not an RNA World? Will other life have an amino acid basis?

There is a paper which suggest that nucleobases can also be found on meteorites though the data is definitely not as robust or the chemistry as simple.