You get 2 pyruvate molecules per glucose. Under aerobic conditions, the pyruvate is taken into the mitochondrial matrix and three modifications occur at the level of the enzyme pyruvate decarboxylase. The two carbons of acetyl CoA are transferred to a four carbon compound, oxaloacetate to produce the 6 carbon compound citrate . For each cycle of the Krebs cycle there are two decarboxylation reactions converting the six carbon compound back to a four carbon compound that can accept two from acetyl CoA and begin the cycle again. Finally, you get one ATP per cycle by substrate-level phosphorylation.
Water is the final electron acceptor .
The yield of ATP under aerobic conditions is about 32-36 per glucose . Light strikes photosystem II and excites electrons. Electrons move from photosystem II to photsystem I by way of plastoquinone and the cytochrome complex. Electrons reaching photosystem I are excited by light absorbed and their energy level is raised. They diffuse through the ATP synthase complex so that ATP is synthesized in the stroma.