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Energy and matter at the Origin of Life – CPS Talk 4/11/14

By Penny Carmichael, on 7 November 2014

– Article by Stephen Leach

 

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LIFE IS A SIDE REACTION OF SOME OTHER MORE EXOTHERMIC PROCESS

Tackling the origins of life was never going to be trivial but oh my, did the CPS audience get pebble-dashed with science last Tuesday night. At the altar was Dr Nick Lane of UCL genetics; author of “Power, Sex and Suicide: Mitochondria and the Meaning of Life”. Dr Lane took us back to a time so distant that the Eukaryotes were still a twinkle in the eye of the Archaea and still further back to when life was just a twinkle in the eye of pH gradients. I can’t tell you what is the origin of life, instead I’ll attempt to recreate here the sense of awe and stupefaction that I felt as I stumbled out of that lecture.

Once upon a time only spiritual leaders would have had the authority to discuss the origins of life. Now, we’ve got NASA, and they say life is:

“A self sustained chemical system capable of undergoing Darwinian evolution”.

Dr Lane’s first gambit was to kill off the idea of a primordial soup, suggesting there is little supporting evidence that life sprang from such a broth. Soup is low energy and high entropy, the precise opposite of life. Wachtershauser was one of the first scientists to suggest that life’s origin has a volcanic context. In what is known as his ‘Iron-Sulfur world’ Wachtershauser suggested that some kind of metabolism predated genetics, an energetic process that could have been a precursor to the ion gradients which now drive the creation of the ATP molecules that power our cells. The only physical characteristic that unites all living things is the transportation of ions up a concentration gradient over a membrane.

All forms of life around today can be classed as bacteria, archaea or eukaryote. The eukaryotes were spawned from the archaea, leaving only two sources. They exhibit significant differences such as their membranes and genetic replication, this suggests they could have developed independently. The crucial similarity between them is the universal notion of membrane energetics, just so happens they have different membranes.

Next we must plunge to the bottom of the ocean to The Lost City Vent Field, these are alkaline volcanic hydrothermal vents and crucially they consist of porous rock and a pH gradient. Dr Lane proposes that these structures could have been the home of ‘LUCA’ the last universal common ancestor.

Here my hazy description becomes hazier still, at this point in the lecture, the rate of information entering my head and the rate of information exiting had balanced. The last legible notation I made was:

“Equilibrium is death”

In short, Dr Lane went on to describe how these vents could have provided the environment that would lead to sort of energetic processes living cells still possess today. In addition he discussed the factors that would need to be added into the model to make sure that the laws of thermodynamics were strictly obeyed but also that equilibrium is never reached because cells in equilibrium; like batteries; expire.

For the last part of the lecture, Dr Lane extensively referred to a paper published last August by himself and some UCL colleagues [1]. If you have institutional access, why not indulge yourself in some avant-garde bioenergetics? Although PLoS Biology, the journal in which you’ll find this paper, is open access, so anyone can look at it!

I felt as though a collection tin could’ve been passed around at the end of the lecture, such was the confusion and elation I felt. It could’ve been the pre-talk double dropped doughnuts wearing off. Either way the origin of life is in safe hands

[1] V. Sojo, A. Pomiankowski, N. Lane. PLoS Biol. 2014 12(8): e1001926​

 

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