Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight into chemical energy. It takes place in the chloroplasts, where chlorophyll absorbs light energy to transform carbon dioxide and water into glucose and oxygen. This process is essential for life on Earth because it provides the oxygen we breathe and forms the base of the food chain. Factors such as light intensity, temperature, and water availability can affect the rate of photosynthesis.