Published Papers

Molecular Architecture and the Processes of Life. May 28, 1948.

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Title:	Molecular Architecture and the Processes of Life [7 of 15]
Creator:	Pauling, Linus, 1901-
Publisher:	Nature.
Date:	1948-05-28
Subject:	Molecular structure
Description:	Nature, vol. 248. Original typescript.
Type:	Text
Format:	text/plain
Language:	en
Identifier:	jessebootlecture-pg07.jpg
Source:	Master scanned with Epson GT-10000+ flatbed scanner at 600 dpi.
Rights:	http://osulibrary.orst.edu/specialcollections/coll/pauling/dna/copyright.html
Full Text:	is determined by an enzyme, the production of which depends upon a single gene. The ability to carry out this oxidation is a character that is inherited phenylketonurea, an invariable symptom of which is idiocy or imbecility. The viruses are vectors of disease that are still smaller than bacteria. Measles, smallpox, and many other diseases are caused by viruses. The study of their nature was difficult before the invention of the electron microscope, because the particles of viruses are too small to be seen in the ordinary microscope, using visible light. There is now strong evidence that the viruses, at any rate the simplest ones, may well be considered as being molecules rather than organisms that have the power of growth. That is, this form of life seems to consist of individual groups of atoms that do not change their nature, once that they are formed, but remain in existence for an indefinite period without change, in the same way that molecules may. This conclusion was suggested by the discovery by Wcndcll Stanley that viruses can be crystallized. In general the reason that a substance can form crystals is that its molecules are identical in shape and size, and so can be piled together in a regular arrangement. The crystallization of viruses by Stanley accordingly indicated that all of the individual particles of a virus are essentially identical with one another in shape and size. This conclusion has been verified, for the simpler viruses, by electron micrographs. The electron microscope has such a large resolving power that it is possible to see extremely small particles, containing only a few thousand atoms. The fundamental particles of, for example, the virus that causes mosaic disease in beans, are seen under the electron microscope to be nearly spherical in shape, and to be all of the same size. They can arrange themselves in a regular array, like a pile of marbles, producing a crystal. Each of these virus molecules contains about one million atoms. Although these molecules may not ordinarily carry out the processes of respiration of air and metabolism of foodstuffs that we usually associate with life, they have one important property that causes us to regard them as living, the property of producing progeny. When the virus invades the tissues of its host, it so influences the chemical reactions that are going on there as to cause the production of many molecules that are replicas of itself, and that are not produced in its absence.