Question

Scientifically, at what point does a cell or cells become a living thing

Answer 1

cells are already living organisms. Life normally requires energy (as for cells is ATP), reacts to the environment ( Example: biological membranes) growth and reproduction.
Single-cell organisms have everything they need to be self-sufficient.

Answer 2

when they start doing the life processes to sustain themselves like exchange of gases,reproduction,nutrition,etc