Scientists have discovered the nitroplast, a newly identified cell structure found in complex cells that can extract nitrogen from the atmosphere and convert it into usable forms for the cell. This groundbreaking discovery is believed to have occurred approximately 100 million years ago, likely evolving from a bacterium taken up by an algal cell, ultimately becoming an integral part of the cell’s metabolism. The nitroplast’s existence marks only the fourth known instance of primary endosymbiosis on Earth, a process where a eukaryotic cell engulfs a prokaryotic cell. This discovery sheds light on the evolution of complex life forms and has implications for understanding the origins of organelles like mitochondria and chloroplasts in plants.