Abiotic Synthesis of Organic Molecules

Two scientists, Dr. Oparin from Russia and Dr. Haldane from Great Britain postulated that life began in a reducing environment. A reducing atmosphere adds electrons to atoms while oxygen steals electrons. A reducing atmosphere was possible because of the tremendous amount of volcanic activity spewing gases into the atmosphere. There was little to no oxygen in the atmosphere.

In the early 1950s, a graduate student, Mr. Miller, and his professor, Dr. Urey, at the University of Chicago, recreated a reducing environment containing water, H₂, CH₄, and NH₃. They then added two energy sources: heat and an electrical spark to mimic lightning. After one week of heating and cooling the liquid broth, they collected samples and found several different organic molecules including amino acids. When other researchers repeated their experiment with different gases they found all 20 amino acids, sugars, lipids, purines and pyrimidines. These are all chemicals found in contemporary living organisms. If the broth contained phosphate, the adenosine triphosphate (ATP) was also formed.

• Could the process described by Miller and Urey occur today? Why or why not?
• Do you think that other nucleotides (other than ATP) could have been formed? Which ones?
• Even if you could obtain monomers, how would polymers be formed in the absence of enzymes which come much later?

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