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These regulatory functions prevent the Calvin cycle from being respired to carbon dioxide. Energy (in the form of ATP) would be wasted in carrying out these reactions when they have no net productivity. [citation needed] The sum of reactions in the Calvin cycle is the following: [citation needed] 3 CO 2 + 6 NADPH + 9 ATP + 5 H
Additional biochemical steps require more energy in the form of ATP to regenerate PEP, but concentrating CO 2 allows high rates of photosynthesis at higher temperatures. Higher CO 2 concentration overcomes the reduction of gas solubility with temperature ( Henry's law ).
The reverse Krebs cycle, also known as the reverse TCA cycle (rTCA) or reductive citric acid cycle, is an alternative to the standard Calvin-Benson cycle for carbon fixation. It has been found in strict anaerobic or microaerobic bacteria (as Aquificales ) and anaerobic archea .
The "machinery" is similar to that in mitochondria except that light energy is used to pump protons across a membrane to produce a proton-motive force. ATP synthase then ensues exactly as in oxidative phosphorylation. [28] Some of the ATP produced in the chloroplasts is consumed in the Calvin cycle, which produces triose sugars.
A cost of 1 ATP is associated with conversion to 3-phosphoglycerate (PGA) (Phosphorylation), within the chloroplast, which is then free to re-enter the Calvin cycle. Several costs are associated with this metabolic pathway; the production of hydrogen peroxide in the peroxisome (associated with the conversion of glycolate to glyoxylate).
The by-product pyruvate can be further degraded in the mitochondrial citric acid cycle, thereby providing additional CO 2 molecules for the Calvin Cycle. Pyruvate can also be used to recover PEP via pyruvate phosphate dikinase, a high-energy step, which requires ATP and an additional phosphate. During the following cool night, PEP is finally ...
Energy in the form of sunlight; The light dependent reactions take place when the light excites a reaction center, which donates an electron to another molecule and starts the electron transport chain to produce ATP and NADPH. Once NADPH has been produced, the Calvin cycle [1] proceeds as in oxygenic photosynthesis, turning CO 2 into glucose.
Aerobic respiration requires oxygen (O 2) in order to create ATP.Although carbohydrates, fats and proteins are consumed as reactants, aerobic respiration is the preferred method of pyruvate production in glycolysis, and requires pyruvate to the mitochondria in order to be oxidized by the citric acid cycle.