AP BIOLOGY

Detailed explanation-1: -A continuous electrical spark was discharged between a pair of electrodes in the larger flask. The spark passed through the mixture of gases and water vapor, simulating lightning in the hypothesized primordial atmosphere of the earth.

Detailed explanation-2: -Miller’s experiment mimicked lightning by the action of an electric discharge on a mixture of gases representing the early atmosphere, in the presence of a liquid water reservoir, representing the early oceans.

Detailed explanation-3: -But to refresh your memory: in 1952 Stanley Miller and Harold Urey simulated the conditions of early Earth by sealing water, methane, ammonia and hydrogen in a glass flask. Then they applied electrical sparks to the mixture. Miraculously, amino acids came into existence amid the roiling mixture. It was a big deal.

Detailed explanation-4: -Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture and chemical reaction occur which produces amino acids such as glycine and alanine, a monomer of protein. Thus, the correct answer is option E.

Detailed explanation-5: -In this brilliant experiment, Miller and Urey demonstrated that electrical sparking a mixture of methane, ammonia, and hydrogen in the presence of water produces amino acids within a variety of organic compounds.