Hacker News new | ask | show | jobs
by fsckboy 963 days ago
The smallest things in your body that have a metabolism are your cells. Cells are much much bigger than viruses. The things in your body that are the same size as viruses also do not have a metabolism.

It's sort of like there's an engine in your car. But there's not an engine in your engine, there are just parts that together make an engine. None of those parts have car-ness, but together they do. Your car has many parts all working together to make a comfortable and useful car. But the parts of the car if they are separated and just sitting on the bench, just sit there.

Viruses are like those parts, car parts. When they are not in a cell, they just sit there. But if a virus part gets into your car, it gets to participate in the metabolism of the whole car, by acting like one of the other parts and just contributing its part-in-the-system. Unfortunately, the virus part's part-in-the-system is to turn your car into a factory/machine that makes more virus parts. This is how it spreads. This is why you do not want to get a virus.

In this news story, a virus that is missing a piece of how to be a functioning part in your car, attaches to another virus that has that missing piece, and together they behave like a part that knows how to become one of your car parts.

3 comments

“You, sir, have been reared in great luxury as becomes your noble birth. How did you come here, by foot or in a chariot?”

“In a chariot, venerable sir.”

“Then, explain sir, what that is. Is it the axle? Or the wheels, or the chassis, or reins, or yoke that is the chariot? Is it all of these combined, or is it something apart from them?”

“It is none of these things, venerable sir.”

“Then, sir, this chariot is an empty sound. You spoke falsely when you said that you came here in a chariot. You are a great king of India. Who are you afraid of that you don’t speak the truth?”

https://en.wikipedia.org/wiki/Milinda_Panha

The Buddhist Ship of Theseus?
It’s a little different. Theseus is about identity over time. This is about identity of wholes from parts. No part of your engine is itself an engine, nor is a collection of engine parts in the wrong arrangement an engine. You need the right parts and the right relationship between the parts. But “right relationship” is not an entity over and above the parts either.
Okay so following your analogy, viruses are like subcomponents of an engine.

How are subcomponents of an engine moving in space without ever exerting energy? I can imagine how this can happen infrequently but can't see how this propagation (movement without energy) is sustainable.

They’re like seeds in the wind. This also means most viruses will never infect a cell. Maybe thinking of them like infected usb drives strewn across the ground hoping some unsuspecting cell picks them up will help.
>They’re like seeds in the wind.

I like this analogy, I'll just take it a bit further: they are seeds in the wind where the wind is a snuffly and moist sneeze aaachoooooo, spraying the seeds all around.

some viruses can sit and survive on a door handle and get passed that way (your hand on then handle, then you rub your eyes) This is called "fomite transmission". Other viruses cannot survive sitting on a door handle outside of your body. The HIV virus can only be passed directly from one person to another in moist body fluids, and not "through" normal dry skin. From this we can see why cold and flu spread so easily, and even though HIV does not, it still has very little trouble finding pathways to transmit.

early in Covid, it was unknown how it spread. In certain ways we still don't know. Do masks work? A lot or a little? the whole thing became so politicized it's still hard to get good information.

> Do masks work? A lot or a little?

I truly don't believe this is the relevant question.

The questions society should be asking is this: "What percentage of the populace properly handles and dons masks? What percentage of the populace replaces or washes those masks thoroughly enough to prevent transmission? What percentage of the populace refuses to don a mask?

Answering these questions truthfully would provide a better coverage graph and allow researchers to find ways to increase the coverage and educate the public accordingly.

I was not trying to answer or even ask the mask question, I was using something the newbies (to virology) here would already be familiar with to point out that even though we know a good bit about viruses, experts still don't automatically know things like "how does this virus propagate", it takes time to tease out the answers and they don't always come.

It's a bit like yesterday's story here about massive amounts of evaporation of water occurring by a mechanism that science never knew about, just to point out that there is much to know that we don't know yet, and not to go deeper into evaporation where science is already struggling.

> "What percentage of the populace properly handles and dons masks? What percentage of the populace replaces or washes those masks thoroughly enough to prevent transmission? What percentage of the populace refuses to don a mask?

While those questions are somewhat useful, ultimately masks still help in any case.

If half the population doesn't wear a mask, masks won't work as well as they would if 100% of the population did, but they would still make a difference. If people don't wear or care for masks correctly it still doesn't make those masks useless because putting literally anything in front of somebody's virus spewing face holes helps a lot regardless.

This is why we teach children to "vampire cough", not because every single person on earth is going to do it 100% of the time, or because people's elbow pits provide N95 levels of protection, but because neither of those things is necessary for it to make a massive difference in the spread of illness.

Sheer random chance.

I had this same question while working on structural resolution of a certain RNA polymerase.

I asked "okay so if this ratcheting mechanism allows the protein to zipper along the nucleotide strand... what's pushing it along?"

The answer is that nothing is pushing it along. It's just random movement and enough time (milliseconds) plus a ratcheting mechanism to ensure it doesn't go backwards.

Our low level processes are not so different from viruses in this respect!

Movement without energy is possible due to diffusion. Imagine you had a room with cellophane separating one side from another. Each side has a different gas, but both gasses are at the same pressure and at room temperature. Then, the cellophane is removed. Without adding any energy to the system, these gasses will mix until the whole room is a perfect mixture of the two gasses, simply because they both diffuse through the entire room. Something similar happens to allow viruses to move through your body (and, if they can be aerosolized, through the air).
Using the analogy, they are like loose screws or other basic machine parts that fell down the pipe, got in the engine, jammed a bunch of things cause they aren't supposed to be there, and consequently a bunch more misc scrap metal got sneezed out the exhaust pipe.
This analogy was really great. Thank you.