(Up to: Philosophy )

Some initial definitions...

Death

When we die, it is a passing of both our mind and our body into a place that we cannot reach whilst alive. By convention, both of these parts must be gone in order for something to be truly dead. A person with a useless, atrophied body, but with a highly agile brain, is clearly alive. On the hand, a person who's brain has withered, yet remains physically stable, is still technically alive. It is only when both are gone that we are said to die.

Life

There is more controversy over when something is brought to life and when not. A baby is clearly alive when it is born, and many argue that it is alive well before being brought fully into our world.

However...

We consider plants to be alive and we consider simple creatures to be alive, despite the fact that they may not have "awareness" as we have it.
But if we were to create something that mimiced perfectly the movements of a plant, or of a cockroach, as a electro-mechanical entity, then we would not claim it as "alive".

Similarly, we can know how things work, and we can recreate them a la cloning/DNA manipulation, etc, and then we would claim that such a thing is alive.

Conclusion...

"Life" and "Death" are completely arbitrary, and possibly only serve as conveniences. Conveniences that restrict the way we think about nature, though?