Iron-sulfur clusters are small, inorganic structures made up of iron and sulfur atoms. They play a crucial role in various biological processes, particularly in metabolism and electron transport. These clusters can exist in different forms, depending on the number of iron and sulfur atoms involved, and they are essential for the function of many proteins and enzymes. In living organisms, iron-sulfur clusters are involved in important reactions, such as photosynthesis and cellular respiration. They help facilitate the transfer of electrons, which is vital for energy production. Their unique properties allow them to participate in redox reactions, making them key components in the biochemical machinery of cells.