5 ms·
As a biochemist, i think it's absolutely clear that viruses are not alive, because they don't do anything. No metabolism, no signalling, no changes in structure
by twic 7y ago
As a biochemist, i think it's absolutely clear that viruses are not alive, because they don't do anything. No metabolism, no signalling, no changes in structure, no use of energy or materials. They just float about! It's only when they encounter a cell that anything happens, and then it's mostly the cell's machinery doing it.
If i was a molecular biologist, i would probably think it was absolutely clear that viruses are alive, because they contain a genome, and proteins encoded by the genome, and they use the proteins to make more copies of the genome. What else is life?
- chmike 7y agoA virus is not able to reproduce itself on its own. Because of that I don't consider virus as a life form. I'm biologist, in case it matters.
- SigmundA 7y agoI cannot reproduce on my own, I need a mate and food and water and air to properly reproduce, that is most life is dependent on its environment to survive including other organisms depending on their needs. A virus needs a host like any parasite, without the host many parasites would not be able to reproduce.
- kazinator 7y agoA virus by itself does not perform any biological functions whatsoever; it just alters the course of events in a host cell. Potassium cyanide can alter what happens in a cell; that doesn't mean potassium cyanide is alive.
- akiselev 7y agoOn a technical level, whether something can reproduce by itself or not is defined by whether they use their own chemical machinery to produce the offspring, such as when a cell divides itself or organisms produce their own gametes. To be pedantic, all you need is at most two (or three, maybe?) of the right gender to reproduce in a vacuum (metaphorically) to make it a living organism. A virus can't reproduce with another virus that way because it can't do anything on its own other than float around waiting for a host, no matter how many strains you mix it with. The host does the actual reproducing for the virus.
- kazinator 7y agoIndeed; the virus being reproduced is just a side effect of the cell making reproducing actions. Cells can repeatedly produce certain proteins. For instance, a silkworm can spin out a thread of silk. That doesn't meant that molecules of silk are alive because they are reproducing.
- SigmundA 7y agoSilk doesn't go on and reproduce through another silk worm once made its complete. Any parasite that requires its host for reproduction could be said to be a byproduct of the host continuing its biological functions usually at the expense of the host. Nature draws no clear lines, humans apply taxonomy, any line we draw about what is alive and what isn't will be arbitrary. My opinion is a virus is alive as it core process is based on how all life on earth operates through DNA/RNA. That is my arbitrary line, a distinct self contained genetic code that continues to replicate and evolve is alive. If that code can no longer continue replicating successfully it is dead.
- twic 7y agoAre lichen fungi life forms?
- uoaei 7y agoHumans aren't either. We need food and water and a hospitable environment to get to a point where we can do that.
- undersuit 7y agoI think that's a pretty good analogy. Viruses are just as incapable of being considered life as our chromosomes are, until you give them a support network.
- filleduchaos 7y agoThis is a confusion of _can_ and _will_.
- undersuit 7y agoThe virus isn't the lifeform. The virus is just one component needed for the lifeform to exist and reproduce. The lifeform is the infection.
- pas 7y agoSo the lifeform is the disease? I think assigning "lifeform" status to an illness is not really helpful. Viruses are just replicators. Grey/Green/Brown/Bio goo. They are just dumb machines made by brute-forcing (fuzzing) more complex machines' immune systems. Viruses might be a different branch on the RNA-replicator tree. Probably when the first replicators started some found - again via brute-forced mutations - that there are some replicators that they can take advantage of to replicate themselves. And it just seems that closing this security hole is neigh impossible as long as we don't start to seriously tinker with that low level of "life" (eg. cellular machinery, transport, nucleus, messenger and transcription security).
- undersuit 7y ago> They are just dumb machines made by brute-forcing (fuzzing) But that's no different how the rest of biology works. A parasite like Giardia is relatively just a dumb machine brute forcing itself through my immune system.
- filleduchaos 7y agoI think you are narrowing on one phrase and ignoring all of the context around it, which is generally not very conducive to understanding a speaker's point.
- pas 7y agoNo, no, of course not. You're right. The same exploitation of complexity-difference can be observed all the way up the hierarchy. But that doesn't make it "living". (Or if you define liveness on a spectrum, like we sort of do with sentience/consciousness, then viruses are alive like rust is conscious.) It's very likely an invariant of complexity. Trade offs (and friendly turtles) all the way. And of course evolution doesn't optimize for QALY at all. So it's not surprising that it hasn't really spent much resources on closing the gap. And now we try to do it because we do find it a better goal than "just" thriving in every imaginable niche on whatever complexity it's possible. (We want to maintain our complexity plus occupy more niches.)
- achillesheels 7y agoThis is the key point I think: viruses have no metabolism. There is no stable energy transfer with their environment. Their genomic feedback does not promote metabolic growth (ie greater energy transmission rates).
- whalabi 7y agoI'm of the opinion that whether something is alive or not is arbitrary, and depends on your definition. Humans just came up with the word to describe a class of things. You could define biological life in a way that includes or excludes viruses, I would suggest, and be right either way. (Also if a biological virus is alive, is a computer virus alive? It's self-replicating and has DNA in the form of code.)
- Gibbon1 7y agoI have three tests for what's alive and what's not. Those are from most fundamental to least. Fundamentally life is a thermodynamic machine. Takes energy and converts a portion of it to 'work'. Under homeostatic control. There are feedback systems that maintain the integrity of the organism. In theory has a way of reproducing. This more applies to the species as a whole. Since individuals incapable of reproducing are none the less alive. Viruses only meet the last and weaker criteria in my book.
- stjohnswarts 7y agoNot unlike prions? which have some qualities of "life" but really can't be considered as such?