Experimental results, which confirm the nonlinear dynamic behavior of bacterial photosynthetic reaction centers under light-activated conditions, are presented. Different light-adapted conformational states of the reaction centers can be obtained by varying the exposition time. It is shown that the fast and slow equilibration kinetics of the reaction centers reflect the mechanisms of electron transfer processes. The reaction centers possessing light-induced structural changes, which have not relaxed completely before a flash, produce the pronounced slow relaxation component. This slow component splits into two separate components with increase in the exposition time. The amplitudes of the resulting components depend on the light adaptation time.