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  2. Photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Photosynthesis

    Photosynthesis usually refers to oxygenic photosynthesis, a process that produces oxygen. Photosynthetic organisms store the chemical energy so produced within intracellular organic compounds (compounds containing carbon) like sugars, glycogen , cellulose and starches .

  3. Calvin cycle - Wikipedia

    en.wikipedia.org/wiki/Calvin_cycle

    Calvin cycle step 1 (black circles represent carbon atoms) Calvin cycle steps 2 and 3 combined. The enzyme RuBisCO catalyses the carboxylation of ribulose-1,5-bisphosphate, RuBP, a 5-carbon compound, by carbon dioxide (a total of 6 carbons) in a two-step reaction. [6] The product of the first step is enediol-enzyme complex that can capture CO 2 ...

  4. Light-dependent reactions - Wikipedia

    en.wikipedia.org/wiki/Light-dependent_reactions

    In oxygenic photosynthesis, the first electron donor is water, creating oxygen (O 2) as a by-product. In anoxygenic photosynthesis, various electron donors are used. Cytochrome b 6 f and ATP synthase work together to produce ATP (photophosphorylation) in two distinct ways.

  5. Evolution of photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Evolution_of_photosynthesis

    C 3 photosynthesis is the oldest and most common form. A C3 plant uses the Calvin cycle for the initial steps that incorporate CO 2 into organic material. A C4 plant prefaces the Calvin cycle with reactions that incorporate CO 2 into four-carbon compounds. A CAM plant uses crassulacean acid metabolism, an adaptation for photosynthesis in arid ...

  6. C4 carbon fixation - Wikipedia

    en.wikipedia.org/wiki/C4_carbon_fixation

    C 2 photosynthesis, an intermediate step between C 3 and Kranz C 4, may be preferred over C 4 for rice conversion. The simpler system is less optimized for high light and high temperature conditions than C 4, but has the advantage of requiring fewer steps of genetic engineering and performing better than C 3 under all temperatures and light ...

  7. Photophosphorylation - Wikipedia

    en.wikipedia.org/wiki/Photophosphorylation

    The fact that a reaction is thermodynamically possible does not mean that it will actually occur. A mixture of hydrogen gas and oxygen gas does not spontaneously ignite. It is necessary either to supply an activation energy or to lower the intrinsic activation energy of the system, in order to make most biochemical reactions proceed at a useful ...

  8. Energy flow (ecology) - Wikipedia

    en.wikipedia.org/wiki/Energy_flow_(ecology)

    The first step in energetics is photosynthesis, where in water and carbon dioxide from the air are taken in with energy from the sun, and are converted into oxygen and glucose. [7] Cellular respiration is the reverse reaction, wherein oxygen and sugar are taken in and release energy as they are converted back into carbon dioxide and water.

  9. C3 carbon fixation - Wikipedia

    en.wikipedia.org/wiki/C3_carbon_fixation

    Calvin–Benson cycle. C 3 carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, the other two being C 4 and CAM.This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction: