The process of photosynthesis' light-dependent reactions occurs in the thylakoid membranes of chloroplasts. This stage requires sunlight, which is captured by chlorophyll and other pigments. Energy from light splits water molecules, releasing oxygen as a byproduct and generating energy-rich compounds, ATP and NADPH. These compounds are then utilized in the light-independent reactions (Calvin cycle) to convert carbon dioxide into glucose, thus sustaining plant life and contributing to the global carbon cycle.