The primary function of the light-harvesting complexes in photosynthesis is to capture and transfer light energy to the reaction centers of photosystems. These complexes contain pigments, primarily chlorophyll, that absorb specific wavelengths of light, initiating the photosynthetic process. Once the light energy is absorbed, it is converted into chemical energy through the excitation of electrons. This energy is essential for synthesizing ATP and NADPH, which are then utilized in the Calvin cycle to produce glucose. The efficiency of light-harvesting complexes is crucial for optimizing photosynthesis in various light conditions.