bacteriophages-living or nonliving entities?can someone answer this question? - (Oct/23/2006 )

can smeone answer this question that whether bacteriophages are living or non living?Ive got an assignment on this question and dont know where to search.plz help me out

phages are viruses and therfore by definition non-living....

Mike

viruses are host-dependent, that's mean that once they are extracellular they are considered "non-living" particles, and when they enter the cell they start to reproduce as "living" organisms....
viruses are unable to act as other living organisms outside their hosts............

depends on how you define life.

The argument for viruses being non-living is based upon their inability to reproduce outside a specialized environment (a host cell). However, we are also unable to reproduce outside a specialized environment; we need appropriate temperatures, gas pressures with appropriate oxygen partial pressure, nutrients (including such specialized molecules as essential amino acids and vitamins), ... the list could become very lengthy. Are we so much more versatile than the virus? We live in a biosphere that supports us. I expect, just a handful of decades after humans have learned to travel into space by bringing critical components of our biosphere along, viruses will be able to replicate in abiotic systems supplied with the required components by some researcher intent on getting a better grant next time. Are we living, if apart from the biosphere?

and consider obligate intracellular parasites (i.e., c. trachomatis, along with others)

same argument. I think it's a philosophical argument; researchers hold different opinions here.

An example of extremes.

The mimivirus, the largest known virus in the world has a 1.2Mb genome, encoding 911 protein coding genes.

While the smallest genome of obligate intracellular parasites, Carsonella ruddi is 160kB, with 185 genes

The smallest free living cell SAR11, has a genome of 1.3Mb. It has a complete set of biosynthetic pathways

It seems like a matter of drawing an arbitary line.