Chemical reactions can occur when sufficient heat is supplied to overcome the activation energy. In the lab, heating a mixture of substances often overcomes the activation energy. An elevation in temperature increase kinetic energy of the molecules. This provides enough energy to break chemical bonds. This is not feasible in living cells because a change in temperature of this type will cause the proteins to disintegrate and cause cell death. To assist with this problem, cells use biologically active protein catalysts called enzymes to facilitate chemical changes.
