Heme is a complex molecule that plays a crucial role in various biological processes. It consists of an iron atom held within a large organic structure called porphyrin. Heme is essential for the function of proteins like hemoglobin, which carries oxygen in the blood, and myoglobin, which stores oxygen in muscles. In addition to its role in oxygen transport, heme is involved in electron transfer and enzymatic reactions. It is found in many living organisms, including animals, plants, and some bacteria. The synthesis and breakdown of heme are vital for maintaining cellular health and function.