In 1953, the Urey-Miller experiment replicated the atmospheric conditions that may have been present on early Earth in an attempt to identify the chemical origin of life. The study confirmed that organic compounds, including amino acids, could have formed spontaneously under the simulated conditions.
On the other hand, just because these molecules had the potential to form does not mean that they actually did.
A new study from the American Chemical Society may help to finally unravel this mystery. The researchers have produced evidence that interactions between just two small molecules, hydrogen cyanide and water, could have given rise to most of the important precursors of RNA and proteins.
The 1953 experiment was based on the potential role of lightning in forming the building blocks of life. The team simulated lightning by running electrical sparks through a flask containing water, methane, ammonia, and hydrogen. These simple chemicals, which were present on early Earth, reacted to form hydrogen cyanide, formaldehyde, and other compounds that reacted further to make amino acids and biomolecules.
However, many scientists now believe that the hazy atmosphere that lingered over our planet roughly four billion years ago would have made it difficult for high-energy photons, like those found in lightning, to reach the Earth’s surface.
A team of scientists led by Kumar Vanka theorized that heat from the boiling hot ocean waters of the time could have driven the chemical reactions instead of lightning. To investigate, the researchers used an advanced tool that simulates how mixtures of molecules react and form new molecules.
The study revealed that hydrogen cyanide, which was present in Earth’s early oceans, could have created the molecules necessary to produce the amino acid glycine and the precursors of RNA when mixed with water.
According to the ACS team, these reactions were both thermodynamically and kinetically feasible. In other words, they did not require a lot of energy or metal catalysts. The researchers said that the findings open up the possibility of interesting new potential pathways for the chemical origin of life.
The study is published in the journal ACS Central Science.
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