Are red blood cells alive?

[maccha]

I'm reading about the criteria for life and how each of our individual cells are living. Since red blood cells do not fulfill all the criteria for life (do not reproduce) are they still considered alive?

[JackBean]

well, even if you took cells from any other part of your body, they wouldn't survive for long either. But the organism as a whole is living, because it fulfills all the criteria.

[BeyazRus]

I'm reading about the criteria for life and how each of our individual cells are living. Since red blood cells do not fulfill all the criteria for life (do not reproduce) are they still considered alive?

Only the mature Red Blood Cells can not reproduce. Before the maturation, they can reproduce. It's like menopause period (loss of female fertility) in human.

[biohazard]

Heh. Nicely put, BeyazRus (:

Also, it is worth remembering that the criteria of life are vague and artificial anyway. For example, if you freeze a sample of bacteria in liquid nitrogen, their metabolism is completely ceased, yet they are not dead. And metabolism is one "requirement" of life.

Also, nobody thinks eunuchs or (like BeyazRus said, older women) are dead just because they cannot reproduce.

You can replace the genome of an eukaryotic cell or bacterium and replace it with another: which one then is alive, the cell or the genome? Or does the cell die in the process, only to be resurrected whith the new genome? Some say resurrection is reserved only for gods... So what actually are life and death?

I think life is "just" (bio)chemistry, played by the rules of physics - and death is something that happens when the homeostasis of that chemical process is irreversibly terminated. Of course this still doesn't really answer the question, since we have viruses and self-replicating molecules like prions and stuff that force us to simply draw the line somewhere by our artificial human means.