Question: How did a couple of elements and compounds turn into life?

Bruce Alexander answered on 15 Jun 2012:

No-one knows. But many people like to have outlandish theories.

What we do know is that there are key ingredients that are required to make any living organism. All living things contain DNA, RNA and proteins. Each of these are made up of long chains of comparatively simple building blocks that are found in all living things. For example, there are 20 amino acids, the building blocks that make up proteins, that are found in all forms of life. Only 20. Without these 20 amino acids, you would have no life. Similarly, there are only 4 nucleic acids that are found to make up DNA.

So, all life is made up of the same 30 or so molecules, whether it is you, me, a tomato or a germ. So if we mix up these 30 or so molecules in a pot, stir, maybe heat it for a while, would we get a living organism? Sadly, the answer is “no”, it is not that simple. We need other things too. We know lipids and fatty acids are important. These are the things that make up cell walls, and we do not know of any forms of life that are simpler than the cell.

But even something as “simple” as the cell is fiendishly complex. Everything ticks along nicely, the DNA is copied into “messenger” RNA, “messenger” RNA is used as an instruction manual for building proteins, and lipids make the cell walls that hold everything together. But what gives it “life” that means this can chug along on its own?

Who knows. It is bad enough trying to define what life is. Scientists and philosophers still argue about this!