Virus molecule

Viruses (two images)
Left: The avian flu virus, depiction of a virus molecule, with an approximate molecular formula of: CE3HE3OE4NE4PE2SE2Ca50K50, can be viewed as a bound state of thousands of atoms (as particle) or as a giant molecule. Right: a 1941 photo of the hexagonal crystalline structure of the tobacco mosaic virus (discovered in 1933) in its active state inside of a so-called living plant cell. [8] This thereafter blurred the older animal/plant/mineral division of matter. [9] In particular are crystals alive or not? This was a deep question grappled with by those including: Gilbert Lewis (1925), Francis Crick (1966), and Linus Pauling (1969).
In hmolscience, virus molecule, as contrasted with the virus particle, is the modeling of a virus, not as a living organism or contagium vivum fluidum (soluble living germ), that reproduces (by transferring RNA to a host), but rather as a large or giant molecule.

In 1941, Life magazine stated the following about the virus: [8]

“The viruses are a strange order of substance that bridge and obscure the once sharply defined boundary between the living cell and the non-living chemical molecule.”


In 1892, Russian biologist Dmitry Ivanovsky used a Chamberland filter (bacteria filter) to study crushed leaf extracts from infected tobacco plants, concluding that a toxin, smaller than bacteria, might be the cause of the infection. In 1898, Dutch microbiologist Martinus Beijerinck repeated the experiments and became convinced that a new form of infectious agent, which he called contagium vivum fluidum or “soluble living germ”, remained in the solution. The term vivum, of course, is Latin for “that which is alive”, as in vis viva (living force) or vitalism (life force principle); which is synonymous with bio which is Greek for “life”.

Virus: liquid, particle, molecule, or organism?
Beijerinck maintained that viruses were liquid in nature; but this “living liquid theory” was later discredited by American biochemist Wendell Stanley (1904-1971), who proved they were particulate. [1] In his 1961 book Viruses and the Nature of Life, however, Wendell devoted chapters to his vacillating views on whether to consider the virus as a particle, molecule, or living organism. [2]

Is a virus alive?
See main: Are viruses alive?; Defunct theory of life
In 1935, American bio-chemist (chnops-chemist) Wendell Stanley isolated the tobacco mosaic virus, in needlelike crystal form, estimated its molecular weight, and showed that when rubbed on the tobacco plant leaves it produced the tobacco mosaic disease (first described by Adolf Mayer in 1886). Stanley’s work appeared in Science in 1935 and soon made the front page of New York Times, for its sensational aspect that it was the missing link between the living and nonliving. [11]

Virus debate cAre viruses alive?
Left: a 2011 elementary school science class classroom study aid designed to facilitate debate and discussion on the question as to whether a virus is alive or dead. [10] Right: American debater Kate Shuster’s “what is life?” section, from her 2008 book Is There Other Life in the Universe?, which uses the “is a virus alive” query in attempts to resolve the puzzle. [6]
In 1937, Barclay Newman commented on the state of the situation as follows: [12]

“It has astonished the scientific world that a single molecule can be the causative organism of a disease. How can a crystal be made up of living molecules?”

In short, Stanley's findings showed that a virus was a "giant chemical molecule". [11] With its apparent ability to move about, invade, infect, and reproduce, etc., these "life-like" qualities immediately led into questions about the nature of what defines "life".

In 1969, Linus Pauling, in his classic 1969 General Chemistry, devoted the opening sections of his biochemistry chapter to debate the question of whether or not to consider the virus, which he characterized as “the simplest kind of matter thought to be alive”, as correctly: (a) living organism, (b) giant particle, or (c) giant molecule (with a molecular weight of 10,000,000), a query to which, in the end, he remained indecisive about. [3]

In 1972, American geneticist Lila Gatlin, in her Information Theory and the Living System, attempted to redefine life as a “system that both stores and processes the information necessary for its own existence”, and based on this redefinition argued that under this definition the “virus would not be regarded as being alive since it can only store but not process information.” [7]

The query “is a virus alive”, in modern times, is a common chapter section in most microbiology textbooks, where, just as with Pauling, indecisiveness reigns. [4]

The following, for example, is a summary of Luis Villarreal's 2004 Scientific American article "Are Viruses Alive?", in which he takes refuge in the emergence viewpoint, that "life is an emergent property of nonliving things" that appears at some "critical level of complexity or interaction", which of course is slippery code for a non-answer to the question: [5]

“Another way to think about life is as an emergent property of a collection of certain nonliving things. Both life and consciousness are examples of emergent complex systems. They each require a critical level of complexity or interaction to achieve their respective states. A neuron by itself, or even in a network of nerves, is not conscious-whole brain complexity needed. Yet even an intact human brain can be biologically alive by incapable of consciousness, or ‘brain-dead’. Similarly, neither cellular nor viral individual genes or proteins are by themselves alive. The enucleated cell is akin to the state of being brain dead, in that it lacks a full critical complexity. A virus, too, fails to reach a critical state, but it is made from the same fundamental, physical building blocks that constitute a virus. Approached from this perspective, viruses, though not fully alive, may be thought of as being more than inert matter: they are on the verge of life.”


What is life (virus)

See also
Evolution timeline

1. Collier, Leslie, Balows, Albert, Sussman, Max. (1998) Topley and Wilson's Microbiology and Microbial Infections (pg. 3), Volume 1, Virology. Arnold
2. (a) Stanley, Wendell M. and Valens, Evans G. (1961). Viruses and the Nature of Life (§: Virus as a Molecule, pgs. 39-66; § Virus as an Organism, pgs. 67-94; §: The Chemicals of Life, pgs. 151-74). Taylor & Francis.
(b) Wendell Stanley – Wikipedia.
3. Pauling, Linus. (1969). General Chemistry (ch.24: Biochemistry, §24.1: The Nature of Life, pgs. 767-69; §:24.2 The Structure of Living Organisms, pgs. 769-70). Dover.
4. Gargaud, Muriel and Lopez-Garcia, Purificacion. (2011). Origins and Evolution of Life: an Astrobiological Perspective (§: Is a Virus Alive?, pgs. 10-11). Cambridge University Press.
5. Villarreal, Luis P. (2004). "Are Viruses Alive?", Scientific American, Dec.
6. Shuster, Kate. (2008). Is There Other Life in the Universe? (§: What is Life?, pgs. 29-30). Heinemann-Raintree Library.
7. Gatlin, Lila L. (1972). Information Theory and the Living System (pg. 6). Columbia University Press.
8. Author. (1941). “The Viruses: the Narrow Gap Between the Molecule and the Living Cell”, Life (pgs. 77-), Oct 20.
9. Crick, Francis. (1967). Of Molecules and Men (pgs. 4-5). University of Washington Press.
10. Keeley, Page. (2011). Uncovering Student Ideas in Life Science, Volume 1 (The Virus Debate, pgs. 15-16). NSTA Press.
11. James, Laylin K. (1993). Nobel Laureates 1901-1992 (pg. 302). Chemical Heritage Foundation.
12. Creager, Angela N.H. (2002). The Life of a Virus: Tobacco Mosaic Virus as an Experimental Model, 1930-1965 (§:Crystals at the “Threshold of Life”, pgs. 47-78). University of Chicago Press.

External links
Virus – Wikipedia.

TDics icon ns

More pages