The part of the plant responsible for photosynthesis is the leaf, specifically the cells found within the leaf known as mesophyll cells. These cells contain chloroplasts, which are organelles that house chlorophyll, the green pigment that captures sunlight. During photosynthesis, chlorophyll absorbs light energy, which drives the conversion of carbon dioxide (taken in through small openings called stomata) and water into glucose and oxygen. This process is essential for plants as it allows them to produce food for growth and energy, while also releasing oxygen into the atmosphere, which is vital for most living organisms.