Plants carry out cellular respiration, generating chemical energy for the activities of the organism. Cells in the leaves and stems of plants perform photosynthesis, which uses the energy of sunlight to synthesize the carbohydrates used in cellular respiration. Mitochondria perform cellular respiration, while chloroplasts perform photosynthesis.
Cellular respiration is a three-stage process composed of glycolysis, the Krebs cycle and electron transport.
Glycolysis converts pyruvate, the end product of photosynthesis, into acetyl-CoA. The Krebs Cycle processes the acetyl-CoA into the unstable electron-carrying chemicals ATP and NADH. The electron transport system uses a chemical energy gradient over specialized membranes to capture energy in the form of ATP.