Photosynthesis occurs in the chloroplasts of plant cells and some algae. These organelles contain chlorophyll, the green pigment that captures sunlight necessary for the process. In photosynthesis, chloroplasts convert light energy, carbon dioxide, and water into glucose and oxygen. This process is vital not just for plants, as it produces the oxygen necessary for the survival of most organisms on Earth and serves as the foundation for the food chain, as plants synthesize energy-rich organic compounds critical for all life forms.