Nice question, not even a sniff of religion anywhere !
It is to do with integrity or cohesion or co-ordination.
Take a perfectly good motorcar, dismantle it, all the parts are there,
the mass and chemistry are the same, but it doesn't work. It's "dead".
Even throwing some petrol at it is only likely to start a fire.
A dead cell (unless a component has obviously malfunctioned) has lost
its co-ordination.
Peter, Reading.