Photosynthesis. Do you know how plants make their own food? Plants prepare their own food by a process called photosynthesis. Photo is the Greek word for light and synthesis is the Greek word for putting together. Plants need sunlight, carbon dioxide from air and water from soil to prepare their own food. Photosynthesis takes place in the leaves of a plant. Leaves have tiny pores called stomata through which carbon dioxide enters the plant. Plant cells contains tiny structures called chloroplasts that contain chlorophyll. Carbon dioxide and water, in the presence of sunlight and chlorophyll get converted into glucose and oxygen. Oxygen then leaves the plant through the stomata. Glucose gives nourishment to the plant. The extra glucose produced is stored by the plant in the form of starch for later use. Photosynthesis is the process by which plants prepare their own food using carbon dioxide and water in the presence of sunlight.