The redox reaction involves the transfer of a single or multiple electrons from one reactant to another. Another name for this process is the oxidation-reduction reaction. Oxidation is known as the loss of electrons from a substance but reduction is the adding of electrons to a separate substance. For example, in cellular respiration, the molecule glucose loses electrons in hydrogen atoms and has just demonstrated oxidation. But in the meantime, oxygen gains electrons in hydrogen atoms demonstrating reduction. The food-creating redox reactions of photosynthesis involve an uphill climb in plants. In this process, when the molecules of water are split apart to give oxygen, they are oxidized. They have lost electrons and hydrogen ions. But in the meantime, carbon dioxide is reduced to sugar as electrons and hydrogen ions are added to it. Plants perform both photosynthesis and cellular respiration, which are both redox reactions.