Published online 8 November 2010 | Nature | doi:10.1038/news.2010.590
Column: Muse
Some like it hot
If heat is needed to kickstart life, water may be the only crucible, argues Philip Ball.
Philip Ball
Should we be surprised to be here? Some scientists maintain that the origin of life is absurdly improbable — Nobel laureate and biologist George Wald baldly stated in 1954 that "one has only to contemplate the magnitude of [the] task to concede that the spontaneous generation of a living organism is impossible"1. Yet others look at the size of the cosmos and conclude that even such extremely low-probability events are inevitable.
One might reasonably argue that the question has little meaning while we still have only a few hundred worlds to compare, and know next to nothing about most of them. But one piece of empirical evidence we do have seems to challenge the notion that the origin of terrestrial life was a piece of extraordinarily good luck: the geological record implies that life began in a blink, almost the instant the oceans were formed. It is as if it was just waiting to happen — as indeed some have suggested2. Although Darwinian evolution needed billions of years to find a route from microbe to man, it seems that going from mineral to microbe took barely a moment.
Now, Richard Wolfenden and his colleagues at the University of North Carolina, Chapel Hill, say that may be largely a question of chemical kinetics. Just about all the key biochemical processes in living organisms are speeded up by enzyme catalysis. Otherwise they would happen too slowly or indiscriminately to make metabolism, and life, feasible. Some key processes, such as reactions involved in biosynthesis of nucleic acids, happen at a glacial pace without enzymes. If so, how did the earliest living systems bootstrap themselves to the point where they could sustain and reproduce themselves with enzymatic assistance?
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Read more here/Leia mais aqui: Nature
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PERGUNTA CAUSTICANTE DESTE BLOGGER:
Bem recentemente não tinha sido proposto que a origem da vida, o Mysterium tremendum, tinha ocorrido com temperaturas bem geladas? Vide este artigo:
Ice as a protocellular medium for RNA replication
James Attwater, Aniela Wochner, Vitor B. Pinheiro, Alan Coulson & Philipp Holliger
doi:10.1038/ncomms1076
Received 20 May 2010 Accepted 23 August 2010 Published 21 September 2010
Fui, sem entender mais nada sobre a origem da vida: uma hora está quente, outra hora está frio, igual aquela brincadeira de crianças...
O estilo baconiano de se fazer ciência é ir à natureza e fazer perguntas a ela. Nem sempre a natureza responde, e o Mysterium tremendum, para desespero da arrogância científica, ela se recusa responder, e continua Mysterium tremendum. Pra desespero de alguns cientistas que não sabem dizer: eu não sei!!!
