Lesson 1 Matter and Energy in Ecosystems – Dutch learned how light energy is used to make sugars from carbon dioxide and water through the process of photosynthesis. In organisms food moves through a series of chemical reactions and the molecules are rearranged to support growth or release energy. Plants, algae, and microorganisms use the energy from light to make food from carbon dioxide from the atmosphere and water through the process of photosynthesis. These reactants produce glucose and oxygen. Next he learned that cellular respiration in plants and animals involve chemical reactions with oxygen that release stored energy. In these processes, complex molecules containing carbon react with oxygen to produce carbon dioxide and other materials.