Bacteria, specifically nitrogen-fixing bacteria, convert atmospheric nitrogen gas N2 into organic nitrogen molecules like amino acids through a process called biological nitrogen fixation. This process is essential for life on Earth, as it makes nitrogen available to plants and other organisms in a usable form.The key enzyme involved in this process is nitrogenase, which is responsible for the reduction of atmospheric nitrogen gas N2 to ammonia NH3 . Nitrogenase is a complex enzyme made up of two main components: the dinitrogenase reductase also known as the Fe protein and the dinitrogenase also known as the MoFe protein . These components work together to catalyze the conversion of N2 to NH3.The nitrogen fixation process can be summarized in the following steps:1. The Fe protein dinitrogenase reductase binds to ATP and receives electrons from a donor molecule, such as ferredoxin or flavodoxin. This process leads to the reduction of the Fe protein.2. The reduced Fe protein then binds to the MoFe protein dinitrogenase , transferring the electrons to it. This transfer of electrons is facilitated by the presence of the metal ions molybdenum and iron in the MoFe protein.3. The MoFe protein, now containing the transferred electrons, binds to the nitrogen gas N2 and reduces it to ammonia NH3 through a series of electron transfer steps. This process requires a total of 8 electrons and 16 ATP molecules to produce 2 molecules of ammonia.4. The ammonia produced is then released from the enzyme, and the nitrogenase complex returns to its initial state, ready for another round of nitrogen fixation.5. The ammonia generated can be further assimilated into organic nitrogen molecules like amino acids through other enzymatic reactions, such as the glutamine synthetase and glutamate synthase reactions.In summary, nitrogenase and reductase enzymes play crucial roles in the biological nitrogen fixation process, allowing nitrogen-fixing bacteria to convert atmospheric nitrogen gas into ammonia. This ammonia can then be assimilated into organic nitrogen molecules like amino acids, making nitrogen available to plants and other organisms in a usable form.