The basic difference between the quick & the dead is ability to grow. Biologists feel that if they could understand growth, they might understand what life is. But growth in nature is complicated. Within a growing cell are hundreds, probably thousands of chemical compounds, their molecules weaving in & out, exchanging atoms and energy. Like a nation, the cell imports (absorbs), exports (excretes), and is influenced by its environment: the innumerable chemical substances in the plant or animal juices outside its frontiers.
To study the growth of such a cell is difficult; it involves too many factors. So forward-looking biologists are trying...