Electron transport chains occur in both photosynthesis and c

Electron transport chains occur in both photosynthesis and cellular respiration. What happens to the energy in an excited electron as it passes through the steps of an electron transport chain? What types of molecules is the energy stored in?

Solution

As the excited electron passes through the steps of electron transport chain, it keeps losing energy. This energy released by the excited electron is used to make an ATP molecule from ADP and inorganic phosphate.

ADP + Phosphate    -------->     ADP ~ Phosphate = ATP

Endothermic processes in the cell then use these ATP molecules, which are now storing the energy, to drive the reactions. When the terminal phosphate linkage in ATP is broken using water, the energy equivalent to 30.5kJ/mol is released.