Photosynthesis/Cellular Respiration ATP • The basic unit of useable energy cells need to power their lives is known as ATP. ATP stands for: Adenosine Tri-phosphate. • ATP is organized in the cell mitochondria and released to all parts of the cell. This molecule is effectively the ‘currency’ or ‘money’ that is used to power life. • It is the bonds that hold the Adenosine, Ribose (sugar) and Phosphate groups together that hold the energy. When the molecule is broken apart by cells, this energy is released and used. Photosynthesis • Photosynthesis is an ‘energy storing’ process. Performed only by plants, it harnesses the energy available in sunlight for the purpose of building glucose, a basic sugar molecule organisms use as food. The term comes from the two latin roots ‘photo’ always meaning light, and ‘synthesis’ which means to build. • The essential factor plants have that animals do not, allowing them to perform this function, is the pigment chlorophyll. • Chlorophyll acts like an energy trap, or a rechargeable battery. It collects the energy available from sunlight and then uses that to begin the chemical process that forms glucose. 2 Phases of Photosynthesis • Light Reactions: The first phase of the process. Water is split into oxygen and hydrogen. The oxygen is given off as a waste product, the hydrogen is used by the plant. This is a complex process, but it takes place almost instantly. Steps of light reaction 1. Chlorophyll is energized. 2. Energy created is stored in ATP. 3. Water molecule is split, hydrogen kept and oxygen is given off into atmosphere as ‘waste’. 4. Hydrogen is trapped by a NADP. Chloroplast contain this coenzyme, which is a hydrogen receptor. Steps of the Dark Reactions 1. Carbon dioxide is fixed by RDP (chloroplasts contain ribulose diphosphate or RDP. This is a 5-carbon sugar molecule with two phosphate groups. This is a carbon dioxide receptor. 2. PGA combines with hydrogen and forms PGAL. 3. Glucose is formed. MAJOR IDEA!!!! • Photosynthesis is the bridge between the organic (living) and inorganic (nonliving)world! This is the process in which nonliving building blocks are organized into a carbon based substance that then powers life.