Respiration

Respiration the breakdown of molecules, usually glucose, but sometimes fat or protein, in the body with a release of energy.

Glucose, for example, is respired aerobically (with oxygen) in the human body thus -

C₆H₁₂O₆ + 6O₂ -> 6H₂O + 6CO₂ + energy

C₆H₁₂O₆ -> 2C₃H₆O₃ + less energy

This energy is often used to turn ADP or AMP into ATP, which is then used as a store of energy.