Photosynthesis primarily occurs in the leaves of a plant. More specifically, the chloroplasts within the cells of the leaf are responsible for carrying out photosynthesis. Chloroplasts contain a green pigment called chlorophyll, which captures light energy from the sun and converts it into chemical energy. This energy is then used to convert carbon dioxide and water into glucose (a type of sugar) and oxygen through a series of biochemical reactions. The glucose produced during photosynthesis serves as a source of energy for the plant and is also used for growth and various metabolic processes.