Chloroplasts are crucial organelles found in plant cells responsible for photosynthesis. They contain chlorophyll, the green pigment that captures sunlight, enabling plants to convert light energy into chemical energy in the form of glucose. During photosynthesis, chloroplasts take in carbon dioxide from the air and water from the soil, using sunlight to transform them into glucose and oxygen as a byproduct. This process not only fuels the plant's growth and energy needs but also supports life on Earth by producing oxygen and serving as the foundational source of energy for most food chains.