Photosynthesis is the process by which plants, algae and some bacteria convert light energy and carbon dioxide into glucose and oxygen. Chlorophyll, the pigment present in chloroplasts, absorbs light energy and converts it into chemical energy that is used to drive the synthesis of glucose and other organic molecules. The glucose produced by photosynthesis is then transported to other parts of the plant where it is stored or used directly as an energy source through cellular respiration.

Cellular respiration is the process by which glucose and other organic molecules are broken down into carbon dioxide and other waste products, releasing energy in the process. This energy is then used to produce ATP, the universal energy currency of living cells. Cellular respiration occurs in the mitochondria, organelles present in almost all eukaryotic cells.