Is photosynthesis an endothermic or exothermic reaction?

Photosynthesis is classified as an endothermic reaction because it requires an input of energy in the form of sunlight to occur. During this process, plants convert carbon dioxide and water into glucose and oxygen, utilizing the energy absorbed from light. This energy is stored in the chemical bonds of the glucose molecules, making the overall process one that absorbs energy rather than releasing it.

In contrast, exothermic reactions release energy. Since photosynthesis involves taking in energy rather than producing it, the classification as endothermic is appropriate. Endothermic reactions are characterized by a gain of energy, which is exactly what happens during photosynthesis when plants capture solar energy to drive the synthesis of organic compounds.