Oxidoreductases are a class of enzymes that facilitate oxidation-reduction reactions in biological systems. These reactions involve the transfer of electrons between molecules, which is essential for various metabolic processes. Oxidoreductases play a crucial role in cellular respiration, photosynthesis, and the metabolism of nutrients. These enzymes are categorized based on the type of molecules they act upon, such as dehydrogenases, oxidases, and reductases. Each type has a specific function, helping to convert substrates into products while maintaining the balance of energy and reducing equivalents in cells.