Why are viruses not considered to be alive?

Answer 1

Actually most virologists will argue that viruses are alive. They replicate via a nucleic acid based genetic information system, which most everyone would consider the most significant criteria for life.

For a virus to be considered "living", it would have to meet these standards::

--Reproduce
*Yes, they do that
--Obtain and use energy
*Yes they do that too. They get energy from their environment which happens to be a host cell
--Grow, develop, and die
*Viruses don't do a lot of growing, true, but neither do some bacteria in the conventional sense. Most unicellular orginsims don't develop, so why should viruses be expected to (even though some virus particles do mature). Viruses do die.
--Respond to the environment.
*They do that as well. Many viruses control their replication in response to host conditions
--Resprirate.
*No, viruses don't respire. But then again, some bacteria don't respire in the traditional way and they are considered alive (resprirate isn't actually a word, even in med school)
They can only reproduce with a host cell.
*True, but this is also true of lots of bacteria
In which the virus just uses the host cell's DNA,RNA.
*Not true, viruses use their own DNA and RNA
A virus also does not resprirate.
*We covered this
It does not even feed.
*Again, neither do most unicellular organisms
&& no it does not feed off the host.
*Actually it does feed off the energy of the host
It kills it.
*Only rarely
Viruses replicate until the host cell burst && releases more viruses.
*That's the point. All living things besides plants derive their energy for replication by using or killing other living things
A virus also does not grow.
*Nope, but some bacteria fall into the same category
It does nothing inside the protien coat (capsid).
*Actually some viruses replicate their nucleic acid inside the coat

Answer 2

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Answer 3

To be considered an organism.
You have to meet all the characteristics of life.
Which viruses don't.
There is however, an ongoing debate on whether they are alive or not.
In my opinion && the popular opinion, they are non-living.
For a virus to be considered "living", it would have to meet these standards::
--Reproduce
--Obtain and use energy
--Grow, develop, and die
--Respond to the environment.
--Resprirate.
They can only reproduce with a host cell.
In which the virus just uses the host cell's DNA,RNA.
A virus also does not resprirate.
It does not even feed.
&& no it does not feed off the host.
It kills it.
Viruses replicate until the host cell burst && releases more viruses.
A virus also does not grow.
It does nothing inside the protien coat (capsid).

Answer 4

I think i had seen the explanation in a biology book. It said virus can grow only in DNA of the living and also destroy that DNA too. If the virus is outside of the living, it don't have any activity, but wait to go inside the living to grow. Some kind of virus can wait for a long time, but some can't.

Answer 5

They can't replicate themselves without using the resources provided by their hosts. They basically hijack cells and force them to make more copies of the viruses, I think by using the host cell dna.

Answer 6

http://www.mrs.umn.edu/~goochv/CellBio/lectures/virus/virus.html

Is a virus alive?
Yes - They reproduce which is a definite form of organization. True, they can not do it on their own, yet all living systems are open systems and depend upon their environment for survival.

Answer 7

Because they cannot reproduce. They need a living cell to do that for them.