Photosynthesis uses light energy to make sugars, which can be used later for fuel.
All living things require energy to carry out the functions of life. A photoautotroph is an organism that makes its own food using light energy. It does this through a process called photosynthesis, the process by which autotrophs convert light energy into chemical energy that is stored in organic compounds, such as sugars. Photoautotroph comes from Greek roots: photo– meaning light, auto– meaning self, and –troph meaning food. In photosynthesis, light is captured in special cells, where it is converted to chemical energy. This chemical energy is then used to power the production of sugars. Photoautotrophs use energy provided by light, as well as carbon dioxide (CO2) and water from the atmosphere, to produce carbohydrates; oxygen is given off during this process. These carbohydrates can later be broken down, releasing the energy stored within them. Plants, algae, some protists, and some bacteria are photoautotrophs. Because they make their own food, photosynthetic organisms make up the base of food chains, serving as producers.