We don't know how life began but one of the more fanciful hypotheses is that it began in a primordial soup of organic molecules supplied by meteors, comets, and violent lightening storms. The idea is that the ocean was full of glucose, amino acids, and nucleotides. Glucose and similar carbohydrates supplied the energy for life. Amino acids spontaneously came together to form proteins. Nucleic acids arose by stringing together pre-existing nucleotides or nucleosides.
In the most extreme version, the ocean itself was the primordial soup and concentrations of organic molecules were sufficient to drive the formation of life. A simple back-of-the envelope calculation indicates that the concentration of typical amino acids would have been about 0.1 nM (10-10 M) [Can watery asteroids explain why life is 'left-handed'?]. This is an unlikely scenario [More Prebiotic Soup Nonsense]. You won't get spontaneous formation of polymers in water at that concentration.
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