Water and life problem described in an article in Nature, vol 436, p1084, 25 August 2005. The search of extra-terrestrial life over the past few years has been centred around searching for water in other parts of the solar system. The reason for this is that on earth wherever there is water there is life. Therefore, scientists have assumed that life can evolve wherever there is water throughout the universe. However, Steven Brenner, a chemist at the University of Florida, Gainesville, points out that biological molecules do not function well on their own in water. The molecules that are essential for living cells to function, i.e. DNA, RNA and proteins, consist of long chains of smaller molecules but water tends to spit up the bonds that join the small molecules together.
Brenner claims: “The structure of RNA screams, ‘I did not arise in water!’ ” He goes on to explain that “in about four out of five cases, synthetic organic chemists will avoid using water as a solvent.” But, water is essential for these molecules to function once they have been made. For example, enzymes, large proteins consisting of long strings of amino acids, need to be in water to fold up into their functional three dimensional shapes. Water is also essential for other processes needed for living cells to work, such as dissolving ions and hydrogen bonding. A comment by John Finney of University College, London, “Life on Earth itself is fine-tuned to water – a consequence of it evolving in close association with the medium” is an example of expert ignorance of this basic dilemma.
Editorial Comment: The answer to this dilemma is that there is more to life than just organic chemistry. In the protected and controlled environment of a living cell, water and biological molecules can be made to interact in a purposeful way, but this only works when all components of the cell are assembled together. The comment about RNA is particularly significant because current evolutionary theories claim that RNA was the first biological molecule to evolve and life arose from a self replicating “RNA world” – a belief that is obviously and now provably wrong.