The Regeneration of ATP ATP is continually regenerated by the cell. Energy to drive the endergonic regeneration of ATP comes from the exergonic process of cellular respiration.
Biochemical reactions require enzymes to speed up and control reaction rates.
Biological catalysts, which are usually proteins. Before a reaction can occur, the reactants must absorb energy to break chemical bonds. This initial energy investment is the activation energy . Unstable condition of reactant molecules that have absorbed sufficient free energy to react. Usually the absorption of thermal energy from the surroundings is enough to break chemical bonds.