Photosynthesis

It has long been known that when exposed to light under suitable conditions of temperature and moisture, the green parts of plants use carbon dioxide from the atmosphere and release oxygen to it. These exchanges are opposite of those which occur in respiration. The process is called photosynthesis. In photosynthesis, carbohydrates are synthesized from carbon dioxide and water by the chloroplasts of plant cells in the presence of light. Oxygen is the product of the reaction. For each molecule of carbon dioxide used, one molecule of oxygen is released. A summary chemical equation for photosynthesis is :

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂