The leaf structure where photosynthesis occurs is called the chloroplast. Chloroplasts are specialized organelles found primarily in the cells of green plants and algae. They contain chlorophyll, the green pigment that captures light energy from the sun, which is essential for the photosynthetic process. During photosynthesis, chloroplasts convert carbon dioxide and water into glucose and oxygen, using sunlight as energy. This process not only provides nourishment for the plant but is also crucial for life on Earth, as it produces the oxygen we breathe and is the foundation of the food chain by providing energy to other organisms.