Photosynthesis occurs in the chloroplasts of plant cells. Chloroplasts contain chlorophyll, the green pigment responsible for capturing sunlight. During photosynthesis, plants convert light energy into chemical energy by transforming carbon dioxide and water into glucose and oxygen. This process not only provides energy for the plant's growth and metabolism but also releases oxygen into the atmosphere, which is vital for the survival of many living organisms. Photosynthesis is fundamental to the Earth's ecosystems, forming the basis of the food chain and influencing global carbon cycles.