An organism that produces its own food is called an autotroph. Autotrophs can synthesize organic substances from inorganic materials, primarily through processes like photosynthesis or chemosynthesis. In photosynthesis, plants, algae, and certain bacteria convert sunlight, carbon dioxide, and water into glucose and oxygen, using chlorophyll as a photosynthetic pigment. Chemosynthetic autotrophs, on the other hand, obtain energy from chemical reactions, often involving sulfur or nitrogen compounds. Autotrophs form the base of the food chain, providing energy for heterotrophs, which cannot produce their own food and rely on consuming other organisms.