If viruses need a living host to live, how is the coronavirus able to survive for so long on surface areas?
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The difficulty lies in the way we use words to shape our thinking. There’s living, and dead, and never alive in the first place, and that’s that.
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1.
The difficulty lies in the way we use words to shape our thinking. There’s living, and dead, and never alive in the first place, and that’s that.
Only it’s not.
A virus is a thing. Put aside notions of “life”. This thing can participate in some very complicated series of chemical reactions which, given favorable circumstances, can result in more copies of the same thing.
Such “favorable circumstances” are to be found inside human beings, and perhaps bats, and not elsewhere. Certainly not on cardboard or metal or plastic surfaces.
On such surfaces, the virus, the thing we’re talking about, is not only not going to go through those complicated processes that make more copies like itself, it’s likely to instead go through simpler chemical and physical processes such as dehydration, severing of chemical bonds due to UV impact, or oxidization due to, well, oxygen in the air. These chemical processes tend to change it from having the possibility of participating, inside a human body, in the complicated processes that result in copies, to not having that possibility.
Going back to less neutral terminology, it gets broken because it’s fragile.
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Viruses are not alive in the sense of cellular biological life. They are collections of DNA or RNA with a surrounding capsule that have as their only function to enter living biological hosts, bind to and enter susceptible cells, commandeer the metabolic processes of those cells and turn them into virus factories which when the cellular protein synthesis is complete and the Cell is destroyed, to exit and infect other cells. In that sense they are nearly the perfect parasite. They generally don’t kill their host but take advantage of the hosts’ energy in order to make more viruses. They have no metabolic function of their own and are only destroyed when Their protective capsule becomes damaged and the interior DNA or RNA is it denatured to the point where it will no longer Serve this purpose .So when they are outside the host they essentially go dormant and have no metabolic needs.
Viruses affect bacteria and plants and virtually every known life form. They are probably as old as cellular life, dating back Over a billion years and have perfectly adapted to their role.
I don’t think we have any idea how many types of viruses there are however
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Viruses need a living host to replicate themselves. Outside host, they act as non-living entities. The survival outside host, on surfaces and in the air depends on the structure of virus.
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The question how is it able to survive on a surface, overlooks the fact that it does not survive at all. It just IS what it IS structurally, a membrane envelope with spikes, and RNA inside. There is no breathing, no metabolism, no heat generation, no energy consumption, no organelles, no locomotion. If the two parts of the virus remain intact, they are as much of a virus as ever. That is why it is difficult for some to regard a virus as life, and you do have to be alive to be killed. Unlike Rodney Dangerfield the dreaded RNA virus does not even deserve the respect it has. To borrow the host cell with its replicative mechanism is a genius way to accomplish its deadly production of generations of offspring. Meanwhile it also borrows bits of the cell wall of the host to become its own invasive envelope. Being a lipid envelope, it does not require water, and does not dry out just sitting there. It does not die of loneliness ror of boredom. It just sits there. The necessity of a host cell to “survive” has to do with the need to replicate more virus.
Question:
How does a virus survive outside a host organism?
By saying survival of viruses, i think you mean how can they stay active outside a host, i.e, without any cell to replicate in. The virulence of a virus when outside a host is one of the major factor which helps in the spreading of the virus from host to host. The virulence of the virus outside the host is maintained for a certain period of time and the time period depends on what virus it is. Also to maintain the virulence, factors like pH of the body fluid it is in and what kind of body fluid it is in and also other factors like temperature etc. Viruses like HIV do not survive for a longer period outside a living host whereas variola viruses like small pox virus can be active even for 2 years.
How does a virus survive outside a host organism?
By saying survival of viruses, i think you mean how can they stay active outside a host, i.e, without any cell to replicate in. The virulence of a virus when outside a host is one of the major factor which helps in the spreading of the virus from host to host. The virulence of the virus outside the host is maintained for a certain period of time and the time period depends on what virus it is. Also to maintain the virulence, factors like pH of the body fluid it is in and what kind of body fluid it is in and also other factors like temperature etc. Viruses like HIV do not survive for a longer period outside a living host whereas variola viruses like small pox virus can be active even for 2 years.
There is a very important distinction between surviving and reproducing. Viruses can survive without hosts alright. But they are essentially dormant until they come into contact with a potential host.
For a virus to be able to reproduce, it would need access to all of a cell's infrastructure and machinery. Essentially, it would have to become a cell. It's easier for them to just hijack (and sometimes become a part of) a pre-existing cell.
For a virus to be able to reproduce, it would need access to all of a cell's infrastructure and machinery. Essentially, it would have to become a cell. It's easier for them to just hijack (and sometimes become a part of) a pre-existing cell.
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It depends on the conditions and the viruses. Viruses are an extremely diverse groups and adaptation to survival outside host would be different for them. Flu viruses, that are most adapted to survival outside hosts ( suspended in aerosols droplets after sneeze for hours) have a pretty complex capside envelope, which is quite stable to pH variations and various proteolitic enzymes. At the opposite, HIV is extremely unstable in external environement.
As such, the capsid plays a pretty important role in adaptation to outside environement, but many other factors also play a role: viruses are pretty complex and modification of non-coding DNA elements might lead to the modification of conditions in which the virus is stable.
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Viruses unlike other "living" organisms don't need food to survive. They are an organised structure of proteins and nucleic acids. They remain latent outside the host body as their structure is complete and stable. Being tiny they aren't threatened by the other Micro organisms. Their only concern would be the pH and temperature as this would denature the proteins. But once inside the host, they reproduce just like it would.
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Viruses unlike other "living" organisms don't need food to survive. They are an organised structure of proteins and nucleic acids. They remain latent outside the host body as their structure is complete and stable. Being tiny they aren't threatened by the other Micro organisms. Their only concern would be the pH and temperature as this would denature the proteins. But once inside the host, they reproduce just like it would.
7.
You will be amazed to hear that a virus is just as same as a dust speck that is it is no different than any other non- living thing.
A virus is just is a RNA or DNA with a protein coat. Scientist even today are not clear if they are (virus) living or non living thing. It behaves like a non living thing outside the body and shows living properties once it gets attached to the host cell.
So you see there is nothing like to survive outside the body until it gets inside you.
They can survive for maybe a few days in the right conditions: not too hot or cold, right pH, no UV radiation, nonporous surface, etc. Viruses are just packets of genetic information in protein shells. As long as the shell is intact the virus is somewhat protected. Once you denature or weaken the shell the genetic material doesn't last long. So for extended periods of time like weeks they need a host to survive.
In viruses..there in nothing like survival outside..
They just become / stay inactive outside host
To elaborate it..
They just become / stay inactive outside host
To elaborate it..
- Viruses are unicelluler(say).
- Now mostly there cell have simple genome.
- This genome codes for those proteins /enzymes that cause penetration and integration of virus within host.
- This genome stay viable for long time (in inactive form) outside the host.
- And when it entes into host it becomed active and starts infecting the host.
There are several factors that cause a virus to inactivate outside of a host. They are all a result of comprimisation of important structures that comprise the viral particle that render it incapable of infecting a host cell. This can be the viral capsule (and envelope if applicable) which can be damaged by anything that can denature proteins including dehydration. The DNA can be damaged by UV radiation. The particle can be consumed by a microbe. Etc.
Normal cell death, of an organism that is (more) living, occurs when the cell reaches equilibrium with its surroundings.
At this point your question is sort of hard to answer because there are many ways that viruses overcome these problems, and this is an important field of research.
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