Cellular respiration might be thought of as a mirror image of photosynthesis.
The Krebs cycle transfers energy to an electron transport chain in the mitochondria, where a small amount of ATP is made. CO2 is released and several ATP are produced.
The overall chemical equation for cellular respiration is:
C6H12O6 + 6O2 --> 6CO2 + 6H2O
sugar + oxygen --> carbon dioxide + water
Go through this animation of Cellular Respiration.