What is the main purpose of the light-dependent reactions in photosynthesis?

The main purpose of the light-dependent reactions in photosynthesis is to convert light energy into chemical energy. During these reactions, which occur in the thylakoid membranes of chloroplasts, sunlight is captured by chlorophyll and other pigments. This energy is used to split water molecules, releasing oxygen as a byproduct, and to generate ATP and NADPH, which are energy-rich compounds.

These products (ATP and NADPH) are essential for the next stage of photosynthesis, known as the Calvin cycle, where they are utilized to convert carbon dioxide into glucose. Therefore, while glucose production is a critical outcome of photosynthesis, it occurs in the subsequent reaction phase, making the conversion of light energy into chemical energy the key function of the light-dependent reactions.