The part of the plant primarily responsible for photosynthesis is the leaf. Leaves contain chloroplasts, which are organelles that house chlorophyll, the green pigment that captures sunlight. Through photosynthesis, plants convert light energy, usually from the sun, into chemical energy in the form of glucose, which serves as food. This process also produces oxygen as a byproduct, which is vital for most living organisms on Earth. The surface area and structure of leaves maximize light absorption, making them essential for the energy needs of the plant.