Geochemistry to biology

Carbon fixation is the process by which living organisms convert carbon dioxide, in the air and dissolved in water, into organic molecules.

Many life forms, including plants, bacteria and microorganisms known as archaea, have different pathways for achieving this. Photosynthesis is one example.

Each of these pathways contains a cascade of enzymes and proteins, some of which contain cores made of iron and sulfur.

We can find proteins with these iron-sulfur clusters in all forms of life. In fact, researchers propose they date back to the Last Universal Common Ancestor – an ancient ancestral cell from which scientists propose life as we know it evolved and diversified.

Iron sulfides are minerals that form when dissolved iron reacts with hydrogen sulfide – the volcanic gas that makes hot springs smell like rotten eggs.