(2) Spontaneous formation of monomeric organic compounds: The simple molecules interact with each to form simple monomeric organic compounds. These molecules were sugar, fatty acids, glycerol, amino acids and organic bases (purine/pyrimidine). The reactions between the inorganic to give simple organic molecules occurs in reducing environment inside ocean. The inorganic molecules were condensed in the form of rain as temperature of earth lower down. Hence, both inorganic compounds and simple organic compounds were present in the primordial ocean.

Figure 4.3 : Different simple organic molecules prevalent on primitive earth.

(3) Spontaneous formation of complex organic compounds: The small, simpler organic compounds react to form complex organic compounds. The simple amino acids reacts to form polypeptides, sugar reacts to form large sugar molecules, fatty acid and glycerol combined together to give fat (Figure 4.4). Heat of the sun is utilized for providing energy for these reactions.