Which compound is primarily responsible for capturing light energy during photosynthesis?

The compound primarily responsible for capturing light energy during photosynthesis is chlorophyll. This pigment is crucial in absorbing light, particularly in the blue and red wavelengths, which are essential for the photosynthetic process. Chlorophyll is found in the chloroplasts of plant cells and plays a vital role in converting light energy into chemical energy. This process starts when light photons hit the chlorophyll molecules, energizing electrons which then initiate the series of reactions that ultimately convert carbon dioxide and water into glucose and oxygen.

While carotenoids and phycobilins also play roles in photosynthesis, they serve as accessory pigments that help capture additional light energy and protect the plant from excess light. However, chlorophyll is the primary pigment directly involved in the light reactions of photosynthesis. Proteins, though essential for various cellular functions, do not capture light energy themselves in the way pigments like chlorophyll do.