Within Photosystem I, Iow energy electrons are reenergized and are passed through an electron transport chain where they are used to reduce the electron carrier NADP+ to NADPH. When the chloroplast is receiving a steady supply of photons, NADPH and ATP molecules are rapidly being provided to the metabolic pathways in the stroma. Therefore the ATP and NADPH formed during the Light Dependent reactions are used in the stroma to fuel the Calvin Cycle reactions. The Calvin Cycle consists of a series of reactions that reduce carbon dioxide to produce the carbohydrate glyceraldehydes-3-phosphate. The cycle consists of three steps, the first of which is carbon fixation. In this step carbon dioxide is attached to ribulose 1,5-bisphosphate resulting in a six carbon molecule that splits into two three carbon molecules. The second step is a sequence of reactions using electrons from NADPH and some of the ATP to reduce carbon dioxide. In the final step, ribulose 1,5-bisphosphate is regenerated. For every three turns of the cycle, five molecules of glyceraldehydes-3-phosphate are used to re-form three molecules of ribulose 1,5-bisphosphate. The remaining glyceraldehydes-3-phosphate is then used to make glucose, fatty acids, or glycerol. It takes two molecules of glyceraldehyde-3-phosphate to make one molecule of glucose phosphate. Thus, the Calvin cycle has to run 6 times to produce one molecule of glucose. These molecules can remove their phosphate and add fructose to form sucrose, the molecule plants use to transport carbohydrates throughout their system. Glucose phosphate is also the starting molecule for the synthesis of starch and cellulose. Plants produce sugars to use as storage molecules and structural components for their own benefit. By utilizing the energy of the sun, along with inputs of water and carbon dioxide, plants act as glucose factories. Photosynthetic organisms are the primary producers of glucose on the planet. They also produce oxygen gas as a byproduct and thus serve as the foundation of life, providing food and oxygen for the complex food webs on both land and in the oceans.
Within Photosystem I, Iow energy electrons are reenergized and are passed through an electron transport chain where they are used to reduce the electron carrier NADP+ to NADPH. When the chloroplast is receiving a steady supply of photons, NADPH and ATP molecules are rapidly being provided to the metabolic pathways in the stroma. Therefore the ATP and NADPH formed during the Light Dependent reactions are used in the stroma to fuel the Calvin Cycle reactions. The Calvin Cycle consists of a series of reactions that reduce carbon dioxide to produce the carbohydrate glyceraldehydes-3-phosphate. The cycle consists of three steps, the first of which is carbon fixation. In this step carbon dioxide is attached to ribulose 1,5-bisphosphate resulting in a six carbon molecule that splits into two three carbon molecules. The second step is a sequence of reactions using electrons from NADPH and some of the ATP to reduce carbon dioxide. In the final step, ribulose 1,5-bisphosphate is regenerated. For every three turns of the cycle, five molecules of glyceraldehydes-3-phosphate are used to re-form three molecules of ribulose 1,5-bisphosphate. The remaining glyceraldehydes-3-phosphate is then used to make glucose, fatty acids, or glycerol. It takes two molecules of glyceraldehyde-3-phosphate to make one molecule of glucose phosphate. Thus, the Calvin cycle has to run 6 times to produce one molecule of glucose. These molecules can remove their phosphate and add fructose to form sucrose, the molecule plants use to transport carbohydrates throughout their system. Glucose phosphate is also the starting molecule for the synthesis of starch and cellulose. Plants produce sugars to use as storage molecules and structural components for their own benefit. By utilizing the energy of the sun, along with inputs of water and carbon dioxide, plants act as glucose factories. Photosynthetic organisms are the primary producers of glucose on the planet. They also produce oxygen gas as a byproduct and thus serve as the foundation of life, providing food and oxygen for the complex food webs on both land and in the oceans.
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