Endergonic Reaction
A reaction with a positive Gibbs free energy change, which requires an input of energy to proceed.
Formula / equation
ΔG > 0
Unit
kJ/mol
In depth
Endergonic reactions have equilibrium constants below one and will not proceed appreciably on their own. Living systems drive them by coupling to strongly exergonic reactions, so that the combined free energy change is negative even though one half is uphill.
Examples in the real world
Photosynthesis, requiring +2870 kJ/mol of light energy; protein synthesis driven by ATP hydrolysis.