How Did the First Organic Structure Form?

Organic compounds are molecules in which carbon and a couple of other elements make up their skeleton. Organic molecules make up all life on Earth, from the thermophiles that live in environments that reach 122ºC to the Pando, an entire forest, of trees are considered one organism.

How are organic compounds formed now?

The most common process for making organic molecules depends on the “reduction” of carbon dioxide. Reduction is a process in which a molecule gains electrons.

Reduction is part of a process called “carbon fixation”; the most common way to do that is photosynthesis. In photosynthesis, a substance, usually water, gets oxidized and gives carbon dioxide some hydrogen atoms (or, if the oxidized substance isn’t water, any other atom that is in organic molecules). Oxidation is the yin to reduction’s yang; it’s the process in which a molecule donates electrons to another molecule. Oxidation cannot happen without reduction, and vice versa.

Why doesn’t this apply to the first organic molecule?

There are a couple of problems with this process:

1: this reaction is endothermic, meaning that it requires energy to happen. Nature is lazy; it preserves energy. That means that carbon fixation didn’t happen until there were live cells to supply the energy. In addition, scientists believe that organisms that can fixate carbon formed relatively recently.

So what was the first organic reaction?

To pinpoint the first organic reaction, we have to think about the molecules that existed at the time. Thankfully, carbon dioxide existed, so we have the reduced molecule, but finding the oxidized molecule is a little trickier. Trace amounts of oxygen existed, but it loved electrons and would never donate them.

Only one possible molecule remains: hydrogen. Its electronegativity is lower than carbon’s (it doesn’t hold on to electrons as much as carbon) and doesn’t require energy to react with carbon dioxide. The scientists at the American Museum of Natural History attempted this reaction and formed formic acid (HCOOH), which is an organic compound.

What do we gain from this discovery?

The reactants in this reaction aren’t exclusive to Earth, and nor are the conditions, which means that this can happen elsewhere in the universe. Life itself can occur elsewhere in the universe. Moreover, this is a way to consume carbon dioxide without costing energy; it may help combat global warming.

Sources

American Museum of Natural History. “Process that might have led to first organic molecules: New research could have relevance to search for extraterrestrial life, green chemistry.” ScienceDaily. ScienceDaily, 8 September 2020. <www.sciencedaily.com/releases/2020/09/200908170535.htm>.

Process That Might Have Led to First Organic Molecules. American Museum of Natural History. (n.d.). https://www.amnh.org/about/press-center/process-that-might-have-lead-to-first-organic-molecules.

Hudson, R., Graaf, R. de, Rodin, M. S., Ohno, A., Lane, N., McGlynn, S. E., Yamada, Y. M. A., Nakamura, R., Barge, L. M., Braun, D., & Sojo, V. (2020, September 15). CO2 reduction driven by a pH gradient. PNAS. https://www.pnas.org/content/117/37/22873.

Malewar, A. (2020, September 19). Study identifies a process that might have led to the first organic molecules. Tech Explorist. https://www.techexplorist.com/process-led-first-organic-molecules/35352/.