Looking for the Logos of Life I

Schrodinger, Erwin. 1967. What Is Life? The Physical Aspect of the Living Cell and Mind and Matter. Cambridge. Cambridge University Press. 178pp.

I wanted to put up this brief post before I launch into some much longer ones on books that purport to extend Schrodinger’s ideas and the tremendous biological discoveries that followed in the ensuing decades. I got started on this when I read another book, Eva Brann’s The Logos of Heraclitus [2011. Paul Dry Books. 160 pp], about which more later.

This is the first of a genre: physicists and chemists look at life. Schrodinger, in these lectures, delivered in Ireland in 1943, introduces the idea that life exists far from the thermodynamic equilibrium that physics sees most systems as tending towards. He is also the source of an idea I first heard when I was a graduate student, that organisms feed on “negative entropy.” The essay is worth reading for the quality of his reasoning and clear exposition, even though his predictions about the nature of the material carrier of heredity turned out not to be quite right.

Just one interesting thought: he points out that whatever molecule the hereditary material consists of carries out its functions in a way different from most of the enzymes in a cell. While most reactions in the cell rely on basically random interactions between molecules, in that you can only predict the general rate of reaction and not whether a specific molecule will react, there’s just one copy of a given gene in each cell. It has to be essentially certain that it will participate when needed in its particular role. Nevertheless, the basic processes of translation and transcription do involve many enzymes, along with the building blocks of nucleic acids and proteins, in what must be the usual sort of collectively predictable, individually unpredictable, dance. DNA is after all, a template, a fixed model against which to construct a product. Keeping that template stable and making sure it is copied correctly is the job of a whole complex set of enzymes in the cell. As Schrodinger points out, a big molecule like DNA can have the stability of a crystal, being held together by essentially the same forces.

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2 thoughts on “Looking for the Logos of Life I”

  1. I was just browsing an article in New Scientist about people coding the Swiss constitution (among other things) in DNA and speculating on how long it would last in cold storage. They used either of two bases for 0 and the others for 1, I guess arbitrarily. Just off the top of my head I wouldn’t imagine DNA as being particularly great for that, but I guess it makes sense when you think about it. Whenever you read about the medium of the future it’s a little hard to tell what to take seriously.

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  2. This leads to the topic of ancient DNA and even antediluvian DNA. The Wikipedia article on ancient DNA cites work suggesting that at -5 degrees C, DNA decays exponentially, such that it would be half gone in 500,000 years (if my mental calculation is correct). Still, it sounds like it might outlast a memory chip or DVD.

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