Eli5: what exactly is a virus and are viruses alive?
A “cell” is like a factory. It has machines that it uses to do normal cell things, and instructions to run those machines. A cell uses those machines and instructions to live, grow, and eventually copy itself, which is called “reproduction.”
On the other hand, a “virus” is just a set of instructions. It has no machines, so it needs to find a cell, a “host,” to put its instructions into. When it does, its instructions take control of the host’s machines. Instead of helping the cell live, the virus’s instructions make the machines create copies of the virus. Eventually, the cell will be so full of virus copies that it bursts open, setting those new viruses free to find new cells to repeat that process.
Are viruses alive? That’s still an ongoing debate. There is no one universally-accepted definition of what can be considered “alive.” Some say that something alive should be able to grow, copy itself, and evolve on its own. Under that definition, a virus is *not* alive – it can’t do those things itself, it needs a host cell. And yet, it has the instructions on how to copy itself, and can do that inside the host…
The short answer is, we don’t know if viruses are alive! They are an edge case where none of our standards completely fit. At least, not *yet.*
3rd year student doctor in the US. Passed board exams and stuff and see patients on my own daily… but this really boils down to your definition of what is life. Which is a constant societal debate. Even among humans in the untited states, we literally have state laws of how long before a fetus is considered a human and it isn’t murder etc… it isn’t a political debate. But the point is it’s subject to *interpetation*. Don’t talk about politics to me reddit. I don’t give a fuck about abortion. I’m simply saying the definition of *life* is subjective. My microbiology professor in undergrad says viruses aren’t alive but my med school micro professor says they are. Life is *popularly* defined as being capable of metabolism and self replication *on your own*. Essentially, cellular function is life. Viruses are not cells. They’re Rouge peices of DNA or RNA.
So essentially it’s up to you to decide if a virus is living or not. There’s no straight up law or 100% defined definition of what life is or not. Viruses replicate? Do they not? That’s an example to some it’s alive.
So it boils down what you’re definition of *life* is. As a pregnant women driving in the HOV-2 lane is illegal her your own. However if someone kills a pregnant women they can be charged accordingly for 2 murders.
So bottom line, viruses being alive depends on your definition of life. Just like abortion. Though it’s unanimously agreed bacteria, protozia, etc.. are life. Viruses are a grey area.
What a virus is: a short set of DNA or RNA inside a protein case.
This DNA/RNA code is used to override the normal cellular machinery of a host cell in order to create many copies of the virus DNA/RNA and its protein case (instead of what it would normally do such as create copies of its own DNA, proteins or cellular functions). It does this until the host cell literally bursts and dies, releasing the new virus particles.
Whether a virus is alive: that’s a trickier question.
Traditionally “living” things have been defined by needing to eat for energy, needing to reproduce, and the ability to change or adapt.
Since viruses typically spend a lot of time in an inert, stasis like state until coming into contact with a suitable host, and having no inherent metabolic processes or requirements in that state, they fall short of the typical requirement of requiring energy and having a method to process it.
They also are obligate parasites in terms of reproduction and change. They can’t reproduce or change outside of the brief period when they are infecting a host cell.
Oso while they don’t meet the traditional requirements kd life, they aren’t dead either. They are somewhere in between.
That said, the definition of life as it pertains to viruses is a hot topic in the scientific community.
Imagine if there was a very specific mineral or chemical composition in the wind that if it touched you, would replicate (likely killing you) then, like a force of nature, release itself to spread further.
There is nothing “living” (as we consider it) about a virus, they’re just a set of stable and complex chemicals which together are able to replicate through actual (confirmed-living) organisms.
It’s difficult to say they’re not alive because they do replicate and they are “complex” as opposed to other materials or chemicals, alloys, or compounds, but there’s nothing “active” about them.
My personal thoughts? Not alive, just an extremely unfortunate variable in the grand scheme of biology. But my major was political science and I nearly died in my bio/Ochem courses so consider this a very, very mildly educated opinion
In general viruses are not considered to be alive. Viruses come in many forms but usually contain (1) a genome that contains the code to make the viral proteins, (2) some proteins that can help the virus enter the cells of an organism as well as kick start its replication (making more viruses) in another organisms cells. Viruses are not considered living because they are highly depended on a host to do anything.