Life! When is something considered "Alive"?
Abiogenesis is the study of how life could arise via natural means. It's a very young science in contrast to other fields of chemistry and biology but is very quickly gaining a lot of good ground with various competing theories supported by various independent lines of research. But before we can go into how life may arise naturally there's one very important question that needs answered. What are the criteria that constitute life? In other words, how do we know when we have achieved life? And for that we need to define what exactly life is...
noun, plural: lives
(1) A distinctive characteristic of a living organism from dead organism or non-living thing, as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce 
Influenza Virus (Click to enlarge)
According to the above definition Viruses are not considered "Alive" even though they can be killed, despite the fact that they also have genes and also evolve. In spite of this, because they don't have a metabolism and are incapable of autonomous reproduction requiring the mechanics of the host cell to reproduce they therefore can't be considered alive by the above definition .
Cellular Life and the Three Domain System
The Cell is the smallest and most basic unit of life of all known living organisms. All known life from that point is classified into one of two groups, unicellular (consisting of only one cell) and multicellular (being made up of multiple cells). All known living cells are one of two basic types, Eukaryotes and Prokaryotes. The Eukaryote cell is distinguished as having a Nucleus to house the genetic material wherein Prokaryotes have no nucleus. Of the two cellular types they've been divided into thee separate Domains (Bacteria, Archea and Eukarya) that stand at the base or crest of the entire Phylogenetic tree.