US scientists said they have taken an important step towardmaking an artificial life form by making a ribosome – the cell’s factory. The ribosome makes the proteins that carry out key business for all forms of life. Messenger RNA carries DNA’s genetic instructions to a cell’s ribosome, which then cooks up the desired protein. Every living organism from bacteria to humans uses a ribosome, and they are all strikingly similar. It is not quite artificial life, but an important step in that direction, said George Church, a professor of genetics at Harvard Medical School, who directed the research with a single graduate student.