text: Most simple molecules are much smaller than the micro level. So I assume you mean macromolecules. \n\n      The main macromolecules in biochemistry are DNA, RNA, protiens, carbohydrates, and lipids. They have their chemical routes with enzymes providing regulation and catalysis.\n\n\n\nMolecules in general are formed in many ways but in general it is through chemical reactions with other molecules. The widely accepted theory is that atoms came to be from nuclear reactions and they came together to form molecules and now we just mixing and matching with the molecules we have for the most part.