I am a virologist. The traditional definitions of life, like that by the first respondent, were written before people knew what viruses were. They are old fashioned definitions that you still find in encyclopedias and Wikipedia.
Viruses are nucleic acid coated in protein and/or lipid. They are extremely efficient at reproducing themselves and spreading between hosts. They evolve like all other life forms.
A better definition of life is: it must contain nucleic acid, be capable of evolving to meet the challenges of its environment, and be self-replicating.
A virus meets all those so it living, but a salt crystal or a fire does not, so they are not living.
Hope this helps.
2006-08-13 18:54:42
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answer #1
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answered by Anonymous
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A virus (Latin, poison) is a submicroscopic particle that can infect the cells of a biological organism. At the most basic level viruses consist of genetic material contained within a protective protein shell called a capsid, which distinguishes them from other virus-like particles such as prions and viroids. The study of viruses is known as virology, and those who study viruses are called virologists.
Viruses are similar to obligate intracellular parasites as they lack the means for self-reproduction outside a host cell, but unlike parasites, which are living organisms, viruses are not truly alive. They infect a wide variety of organisms, both eukaryotes (such as animals and plants) and prokaryotes (such as bacteria). A virus that infects bacteria is known as a bacteriophage, which is used mainly in its shortened form phage.
It has been argued extensively whether viruses are living organisms. They are considered non-living by the majority of virologists as they do not meet all the criteria of the generally accepted definition of life. Among other factors, viruses do not possess a cell membrane or metabolise on their own. A definitive answer is still elusive due to the fact that some organisms considered to be living exhibit characteristics of both living and non-living particles, as viruses do. For those that consider viruses living, viruses are an exception to the cell theory proposed by Theodore Schwann, as viruses are not made up of cells.
2006-08-13 05:45:35
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answer #2
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answered by quatt47 7
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The virus does not meet all of the characteristics used to define living organisms. It does not have a cellular structure and it has no metabolic process. Otherwise it acts like a living thing by entering host cells and reproducing.
2006-08-13 04:30:15
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answer #3
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answered by Waltjh 2
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No. In order to be deemed "living" it must meet the following criteria:
1) Require energy
2) Made of cells
3) Reproduce
4) Display hereditary
5) Respond to the environment
6) Maintain homeostasis
7) Evolve & Adapt
2006-08-13 04:26:59
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answer #4
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answered by jj 1
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Virus is a infective agent .
virus is alive when they had attached with a substance
virus is non living when they have with out substance .
Virus is like a politician
virus is like a dangerous human
Also virus is like a your question
2006-08-14 04:48:20
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answer #5
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answered by winxp 2
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viruses are the connecting link between plants living and non living thigs, in the same way as paramecium is between plants and animal, virus have both the qualities of living and non living, out side the host it is nonliving and inside it is living.
2006-08-13 09:00:52
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answer #6
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answered by Anonymous
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The above 2 answers R good enough
2006-08-13 04:37:53
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answer #7
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answered by BioProf 2
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how can a virus not be living if it infects the body ?
2006-08-13 21:07:15
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answer #8
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answered by Anonymous
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They're non-living because they don't have a ordinary cell. They're just protein coated with information.
2006-08-13 05:12:42
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answer #9
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answered by Science_Guy 4
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