Final answer:
Chloroplasts are organelles in autotrophic eukaryotes that contain chlorophyll to capture light energy for photosynthesis.
Step-by-step explanation:
The organelles responsible for capturing light energy in photosynthetic organisms are called chloroplasts. These organelles contain chlorophyll, a green pigment essential for photosynthesis. Chloroplasts are a type of plastid found in the cells of autotrophic eukaryotes, such as plants and some types of algae. These organelles have a double membrane envelope and internal structures known as thylakoids, which are stacked into grana. Within the thylakoids, chlorophyll captures light energy, which is then used to convert carbon dioxide and water into sugars through the process of photosynthesis, making it essential for plant energy production and growth.