nobody expects the... #1
apoptosis. elucidated? of course not. apoptosis is a greek word used to describe the falling of leaves from trees and/or petals from flowers. in scientific terms, it is used to define programmed cell death or "cellular suicide".
you could ask what's the importance of cell death for a living organism. well, it's extremely important, as it allows the shaping of organs during embryogenesis and the maintenance of homeostasis during adult life. without apoptosis, we wouldn't have fingers (we'd all look like ducks with their interdigital membranes... weird), our brains wouldn't fit our skulls, among many other examples. apoptosis is also important in disease, as too much apoptosis is involved in neurodegenerative diseases, and too little in cancer (hence, why i work in a cancer research centre...)
contrary to common sense or logic, all cells in our bodies are in a "death default state". this means that cells constantly need signals to keep living (finally a cellular explanation for depression...). loss of these survival signals invariably leads to removal of the cell. of course, this is not the only way cells activate its self-destruction program. drugs, chemicals and radiation can also cause cell death.
i won't bore you with the details of my work, as it dwells on the molecular aspects of apoptosis. i leave you with the short note that i work with those tiny little fruit flies that hover around rotting fruit. next time you squash one of them, think of scientific advances...