Photosynthesis & Cellular Respiration What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction on our planet. What is the equation for the chemical reaction of photosynthesis? What is the equation for the chemical reaction of photosynthesis? Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of glucose and six molecules of oxygen. Describe Photosynthesis The process of changing light energy to chemical energy Energy stored as sugar Occurs in plants and some algae Plants need light energy, CO2, and H2O Takes place in the chloroplasts, using chlorophyll, the green pigment in plants What happens during photosynthesis? Plants capture light energy and use that energy to make glucose Sunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucose Oxygen is also released in this reaction What happens during photosynthesis? Carbon dioxide enters the leaf through holes called stomata CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue Why is this important to us? We cannot make our own food (glucose, energy), we must get our food from plants. Plants are the first step in the food chain. The oxygen released during photosynthesis is necessary for all living things. Photosynthesis in Action Let's Look a Photosynthesis in Action Learn more about photosynthesis at: http://www.ftexploring.com/me/photosyn1.html What is Cellular Respiration? The release of chemical energy for use by animal or plant cells to create Biomass (tissue) for growth. How Does Cellular Respiration Work? Once the energy that was in sunlight is changed into chemical energy (sugar) by photosynthesis, an organism has to transform the chemical energy into a form that can be used by the organism. This process is cellular respiration. Describe Cellular Respiration The breakdown of glucose molecules to release energy Takes place in all living things Is a step by step process What is the chemical equation for cellular respiration? +energy Cellular Respiration in Action An analogy can be drawn between the process of cellular respiration in our cells and a car. The mitochondria are the engines of our cells where sugar is burned for fuel and the exhaust is CO2 and H2O. Note that in a car that burned fuel perfectly, the only exhaust should theoretically be CO2 and H2O also. There are three steps in the process of cellular respiration: glycolysis, the Krebs cycle, and the electron transport chain. So why is Photosynthesis and Cellular Respiration important to me? Plants play the most important part in the cycle of nature. Without plants, there could be no life on Earth. They are the primary producers that sustain all other life forms. This is so because plants are the only organisms that can make their own food. Animals, incapable of making their own food, depend directly or indirectly on plants for their supply of food. All animals and the foods they eat can be traced back to plants. The oxygen we breathe comes from plants. Through photosynthesis, plants take energy from the sun, carbon dioxide from the air, and water and minerals from the soil. They then give off water and oxygen. Animals and other nonproducers take part in this cycle through respiration. Respiration is the process where oxygen is used by organisms to release energy from food, and carbon dioxide is given off. The cycles of photosynthesis and respiration help maintain the earth's natural balance of oxygen, carbon dioxide, and water. Read how photosynthesis & Respiration are related: http://www.usoe.k12.ut.us/curr/science/sciber00/8th/e nergy/sciber/photosyn.htm