IS A VIRUS ALIVE?
What does it mean to be living? Viruses certainly seem to accelerate the dying. Well, some of them, anyway. Are they all parasitic?
I ask my Junior College students this question: How do you define life? Not spiritually, for that is not my business here. Not through philosophy, too speculative. But physically, as in reality. Using the reproducibility of the Scientific Method, and the testing of its hypotheses. Maybe that’s it. Reproducibility! Let us see.
Is a rock alive? It can grow in size and be worn down, just like us. From “dust to dust,” it is said, but that is just the Second Law of Thermodynamics.
Water then! It is so silky and smooth, and seems to move like we do. No, that is just oxygen’s polar covalent bonds that lead its hydrogen atoms to attracting other things. But that is something, for we are made of 60% water, with our brains sucking up even more of its weight in that fluid! Maybe we should look for water in our definition of life?
But there is no water in a virus. But there was, once, on Mars.
Oh, stop it! We are not dreaming, here. Although we do seem to want to go to Mars soon! Will we find life there, too? Mars viruses waiting for you?
Okay, life is defined, then, by the cellular life form that it keeps. That will work for our taxonomic Kingdoms: Plants, Animals, Fungi, Protists, and Bacteria. They all have cells. Cells are even present in that oldest of life forms we call Achaean!
Viruses, however, don’t have cells, don’t have cytoplasm. But maybe we are getting at something here. They do have protein coatings and some are enclosed within fatty acid envelopes. But viruses have nothing else inside except protein-protected genetic material.
Now we’ve got it! Life is defined by those self-replicating molecules of genetic data: DNA [deoxyribonucleic acid] and RNA [ribonucleic acid]. Done. Life is that which is genetically propagated!
Wait. Hold on! What about prions? You know [or maybe not?], Mad Cow Disease [remember England in the late 1990s?], Chronic Wasting Disease [in some populations of deer], or Creutzfeldt-Jakob Disease [a rare disease that is always fatal in humans]. Prions have no cells, no cell walls, no envelopes, no genetic material. They are just a tiny folded portion of a protein we call a “prion” [proteinaceous infectious particle].
So what do we do now in our search for life? At least in the puny definition that we need to justify our own existence. Our hypothesis must include all of that described above. And all of that shares one singular trait. Reproducibility. Even prions obey that rule.
But don’t crystals reproduce themselves? Back to rocks again!
Alas, this essay is not based in geologic time. So let us examine these parasitic viral particles a little more closely. And I mean a little. A virus is many thousands of times thinner than one strand of your hair!
Generally, viruses are grouped according to their appearance. Some viruses [like the tobacco mosaic virus] are helical in shape. A shape you can only see with an electron microscope. Others [like polio and herpes] are round and polyhedral in shape, like a soccer ball.
And those creepy drawings of viruses with a head, a long neck, and moon-landing-like legs can infect bacteria [bacteriophages, now there is a scary name!]. Others, including many animal viruses, are encased in an additional double layer of fatty acid armor [similar to our own cellular membranes], interrupted with glycoprotein triggers [protein- carbohydrate complexes].
And what’s inside? Those nucleic acids covered in protective protein slime. The basic description of a parasitic life form. In this case, a virus.
These last kinds of viral particles are made up of all four groups of life’s organic compounds: protein, carbohydrates, lipids, and nucleic acids. That is instructive. And these tiny thugs include the Coronavirus, now a global pandemic!
But we are still not certain how this Coronavirus spreads so rapidly in winter conditions. Although we know that it is airborne, and moves through the dispersal of tiny droplets.
Here are some possibilities that explain this contagion.
We know from Guinea Pig studies [an ironic metaphorical phrase] that the flu virus survives longer in the colder weather when the moisture in air is lower. It is thought that the virus, coughed out, falls quickly to the ground in humid conditions, weighed down by water droplets collected in human lungs.
But in winter, the water droplets instantly evaporate in the low humidity, allowing the tiny viral particle to float upward and farther outward, to you. And the cold, I suppose, is less adverse to the viral envelope. Perhaps also, our immune systems are more stressed in winter. And so it may be with this Coronavirus.
How do soaps kill it? Soap attaches to the viral envelope’s lipid structure, and essentially breaks it apart. Sort of dissolves it. Alcohol and chlorine-based molecules just attack it, and eat up its molecular structure.
So, is a virus alive? It is, if you consider such a structure reproducible. And viruses like the Coronavirus have knobby-like “crowns” [hence the name] composed of more glycoproteins that facilitate entry into the host cell. That’s you.
Once in, the virus’s single-stranded RNA is injected into the cell cytoplasm, attaching to the cells’ ribosomes, which translate the viral genetic code to produce protein and enzymes. Together, these make additional copies of the invader and its structure.
Reproducibility. Viral offspring to cough out in droplets of infection, which either fall to the ground, or dry in the winter air and float around until they infect you!
Here is another view of a viral life cycle. Maybe the infected cell [your cell, if you are infected], with its enslaved reproductive machinery, is the real virus. What if what we call the airborne virus is just a spore-like reproductive organ? Like sperm, egg, or pollen.
Is that what happened in the first Alien movie? Very creepy. Viral parasites reproducing through you.
What do you say now? Is a virus alive?