The role of chloroplasts in photosynthesis is to capture light energy and convert it into chemical energy stored in glucose. Chloroplasts contain the green pigment chlorophyll, which absorbs sunlight, initiating the photosynthetic process. During photosynthesis, carbon dioxide and water are transformed into glucose and oxygen, providing energy for plants and oxygen for other organisms. Chloroplasts are essential for the growth of autotrophic organisms and play a critical role in the global carbon cycle.