Tuesday, January 15, 2008

Wizardology 102 - What is Life?

In 1943, a decade before English biophysicist and crystallographer Rosalind Franklin discerned the fine structure of DNA via X-ray diffraction imaging which formed the framework of Watson and Crick's hypothesis of the double helical structure of DNA in their 1953 publication, one of the original quantum mechanics, Erwin Schrödinger posited an ontogenetic dilemma and offered a novel speculation about the fundamental character of life processes.

In a series of lectures What is Life? – The Physical Aspects of Living Cells (1945), Schrödinger postulated that the answer to this most fundamental question requires a new approach.
A scientist is supposed to have a complete and thorough knowledge, at first hand, of some subjects and, therefore, is usually expected not to write on any topic of which he is not a life master. This is regarded as a matter of noblesse oblige. For the present purpose I beg to renounce the noblesse, if any, and to be the freed of the ensuing obligation. …some of us should venture to embark on a synthesis of facts and theories, albeit with second-hand and incomplete knowledge of some of them -and at the risk of making fools of ourselves. So much for my apology. (Schrödinger 1945, p. vii).....

....Today, thanks to the ingenious work of biologists, mainly of geneticists, during the last 30 or 40 years, enough is known about the actual material structure of organisms and about their functioning to state that, and to tell precisely why present-day physics and chemistry could not possibly account for what happens in space and time within a living organism. (ibid. p. 2).....

What is the characteristic feature of life? When is a piece of matter said to be alive? When it goes on 'doing something', moving, exchanging material with its environment, and so forth, and that for a much longer period than we would expect of an inanimate piece of matter to 'keep going' under similar circumstances. (ibid. p. 70).....

Every process, event, happening – call it what you will; in a word, everything that is going on in Nature means an increase of the entropy of the part of the world where it is going on. Thus a living organism continually increases its entropy – or, as you may say, produces positive entropy – and thus tends to approach the dangerous state of maximum entropy, which is death. It can only keep aloof from it, i.e., alive, by continually drawing from its environment negative entropy...(ibid. p. 72).....

How would we express in terms of the statistical theory the marvelous faculty of a living organism, by which it delays the decay into thermodynamic equilibrium (death)? We said before: 'It feeds upon negative entropy', attracting, as it was a stream of negative entropy upon itself, to compensate the entropy increase it produces by living and thus to maintain itself on a stationary and fairly low entropy level…. Indeed, in the case of higher animals we know the kind of orderliness they feed upon well enough, viz. the extremely well-ordered state of matter in more or less complicated organic compounds, which serve them as foodstuffs. After utilizing it they return it in a very much degraded form -not entirely degraded, however, for plants can still make use of it. (ibid. pp. 74-5)

Focusing on energy, matter and thermodynamic imbalances provided by the environment, Schrödinger proposed the consumption of negative entropy as the fundamental requirement for life, i.e., i.e., the use of thermodynamic imbalances in the environment. Presently, Schrodinger's ontogenetic dilemma is generally considered solved, and his original postulate attributed to the status of knowledge in the pre-DNA era of molecular biology. But the fact of the matter is that the genome-centered paradigm does not satisfactorily address Schrodinger's original intuitions about the nature of life, at all. Despite profound advances in human knowledge of genetic structure, we fundamentally lack a satisfactory framework of explanation for living systems.

1 comments:

TEJASHRI PAWAR said...

thanks for discover an important thing DNA

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