Question

Long answer question.

Describe the Urey and Miller experiment.

Answer 1

Stanley L. Miller and his teacher Harold C. Urey provided the first experimental evidence in support of chemical evolution theory of Oparin.

1. Apparatus and Procedure:

They designed a glass-apparatus called spark-discharge apparatus. The apparatus was first sterilized and evacuated. Methane, ammonia, and hydrogen gases were pumped in the proportion of 1:2:2 into the glass chamber. A tube carrying water vapour was also connected to the chamber. The lightning effect was mimicked by the action of electric discharge in the chamber.
The process of evaporation and precipitation was also stimulated by the use of heating mantle and condenser respectively.
The mixture of CH₄, NH₃, H₂ was exposed continuously to electric discharge for several days causing the gases to interact, after which these were condensed.

2. Observation:

It was observed that the liquid collected in the U-tube turned brown.

3. Results and Conclusions:

Chemical analysis of this liquid reported the presence of simple organic compounds. (urea, amino acids, lactic acid, etc.). This experiment strongly supports that the simple molecules present in the Earth’s early atmosphere combined to form the organic building blocks of life.