If DNA needs enzymes to work and enzymes need DNA to be made, how are enzymes made in the first place?
In: Biology
DNA is a stable form of RNA. Both carrying genetic code. However plenty of RNA molecules are themselves enzymatically active. So the most likely explanation is at some point a piece of RNA randomly formed, that had the ability to copy RNA. From that point on you just need evolution. Since proteins are much more stable than RNA, any time rna came about that could create protein from reading an rna template rather than new rna, it would propagate. Enzymes don’t have to be different to rna. Enzyme just refers to a property of a molecule to catalyse some chemical reactions. In modern life forms most enzymes happen to be proteins, i.e. made from amino acids. But RNA just refers to the chemical structure of a molecule. So it can be inert or it can itself be enzymatically active. As for how life came to be: cell membranes are easy. Those happen any time you put a bit of soap in water. The individual soap molecules align to keep their lipophilic parts together and the hydrophilic parts to the water. Cell membranes are no different. They are just heavily stabilised fatty acid bilayera. Over hundreds of millions of years the living cells that preclude all our modern live evolved to put specificity modified fatty acids and peptides into their cell membranes to make them more stable. But in a mild environment, a pure phospholipid bilayer cell membrane is perfectly stable. So you end up with some small pond containing the individual rna building blocks and the lipids for cells. Randomly arranged rna ends up in such a lipid bilayer membrane and starts producing more of itself. And by random chance we eventually end up with modern cells.
Basically this step only had to happen once millions of years ago.
From then on it was a continuous cycle of RNA/DNA being read by enzymes making more enzymes which in turn replicated the DNA/RNA.
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