Which molecule is responsible for absorbing light in plants?

The correct answer is chlorophyll, which plays a crucial role in photosynthesis by absorbing light energy, primarily from the blue and red wavelengths of the light spectrum. Chlorophyll is the main pigment found in the chloroplasts of plant cells, and it is essential for converting light energy into chemical energy. This process occurs during the light-dependent reactions of photosynthesis, where chlorophyll captures light energy and uses it to split water molecules, releasing oxygen and generating energy-rich molecules like ATP and NADPH.

While riboflavin, carotenoids, and xanthophylls are also related to light absorption, they either play secondary roles or are involved in different functions. Riboflavin is a vitamin that does not primarily function in photosynthesis. Carotenoids and xanthophylls are pigments that absorb light as well, but they mainly protect the plant from excessive light and oxidative damage rather than being the primary molecules responsible for the initial light capture needed for photosynthesis. In summary, chlorophyll's role in directly capturing and converting sunlight into usable energy makes it the key molecule for this process in plants.