The Fats Of Life?

June 16th, 2009at 07:34am Posted by Eli

It looks like biologists are closing in on the answers to some longstanding questions about how life first evolved:

The origins of life on Earth bristle with puzzle and paradox. Which came first, the proteins of living cells or the genetic information that makes them? How could the metabolism of living things get started without an enclosing membrane to keep all the necessary chemicals together? But if life started inside a cell membrane, how did the necessary nutrients get in?

(…)

The three researchers, Jack W. Szostak, David P. Bartel and P. Luigi Luisi, published a somewhat adventurous manifesto in Nature in 2001, declaring that the way to make a synthetic cell was to get a protocell and a genetic molecule to grow and divide in parallel, with the molecules being encapsulated in the cell. If the molecules gave the cell a survival advantage over other cells, the outcome would be “a sustainable, autonomously replicating system, capable of Darwinian evolution,” they wrote.

(…)

Simple fatty acids, of the sort likely to have been around on the primitive Earth, will spontaneously form double-layered spheres, much like the double-layered membrane of today’s living cells. These protocells will incorporate new fatty acids fed into the water, and eventually divide.

Living cells are generally impermeable and have elaborate mechanisms for admitting only the nutrients they need. But Dr. Szostak and his colleagues have shown that small molecules can easily enter the protocells. If they combine into larger molecules, however, they cannot get out, just the arrangement a primitive cell would need. If a protocell is made to encapsulate a short piece of DNA and is then fed with nucleotides, the building blocks of DNA, the nucleotides will spontaneously enter the cell and link into another DNA molecule.

IANAB (I am not a biologist), but this does sound promising.  Cell formation isn’t the only question about how life got started – the article goes on to describe advances in understanding RNA replication, nucleotide pair formation, and some things about the “handedness” of the various component molecules.  Fascinating stuff.

Entry Filed under: Coolness,Science


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