Which type of organic molecules were demonstrated to form spontaneously under Miller-Urey-like simulations of early Earth conditions?

• A. Amino acids
• B. Nucleotides
• C. Simple sugars
• D. Fatty acids

Answer: (A)

Energy input driving chemistry that could resemble early Earth shows how simple inorganic molecules can assemble into more complex organics. In Miller-Urey-like simulations, a mixture of basic gases was shocked with sparks to mimic lightning, and amino acids—the building blocks of proteins—formed spontaneously. This result demonstrates that essential organic components can arise from nonliving chemistry under plausible early Earth conditions, supporting the idea that the precursors of life could emerge without biological catalysts.

Nucleotides, sugars, and fatty acids are more complex to assemble under those same conditions, so they are not the classic products demonstrated by the original Miller-Urey setup.