The mechanism that allows plants to capture sunlight for photosynthesis is the presence of chlorophyll in chloroplasts. Chlorophyll is a green pigment that absorbs light energy, primarily from the sun, converting it into chemical energy. During photosynthesis, plants take in carbon dioxide and water, using sunlight to synthesize glucose and oxygen. This process not only supports plant life but also forms the basis of the food chain by providing energy for other organisms. Understanding this mechanism is crucial for enhancing agricultural practices and exploring renewable energy sources.