enter image description here I was looking at this image and reading through the Wikipedia page for viruses and it says that to satisfy the definition of "being alive" the organism must have a cellular structure, but it seems to me that if an organism has all these other factors without a cellular structure, it is still seemingly alive, no?

So why exactly does an organism need a cellular structure to be alive? What is the rationale for that criteria?

  • $\begingroup$ A quote I remember from the Campbell's Biology textbook said something like "if you take all the individual components of a chloroplast and put them all together in a tube, you won't have a functional chloroplast"... That's why the structure of a cell and its organsiation matter, even if it doesn't explain why the structure is absolutely necessary for a cell to work. Similarly, the textbook would say that having all the pieces of a bike in a box won't lead you anywhere, but a little bit more structure could make a bike and lead you somewhere. I hope these examples can help. $\endgroup$
    – justdoit
    Jan 17 '18 at 7:03