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The following is a breakdown of the energetics of the photosynthesis process from Photosynthesis by Hall and Rao: [6]. Starting with the solar spectrum falling on a leaf, 47% lost due to photons outside the 400–700 nm active range (chlorophyll uses photons between 400 and 700 nm, extracting the energy of one 700 nm photon from each one)
Propane was first synthesized by the French chemist Marcellin Berthelot in 1857 during his researches on hydrogenation. Berthelot made propane by heating propylene dibromide (C 3 H 6 Br 2) with potassium iodide and water. [9] [10]: p. 9, §1.1 [11] Propane was found dissolved in Pennsylvanian light crude oil by Edmund Ronalds in 1864.
Cornelis Van Niel made key discoveries explaining the chemistry of photosynthesis. By studying purple sulfur bacteria and green bacteria , he was the first to demonstrate that photosynthesis is a light-dependent redox reaction in which hydrogen reduces (donates its atoms as electrons and protons to) carbon dioxide.
Their experiment proved the existence of a photosynthetic unit. Gaffron and Wohl later interpreted the experiment and realized that the light absorbed by the photosynthetic unit was transferred. [7] This reaction occurs at the reaction center of Photosystem II and takes place in cyanobacteria, algae and green plants. [8]
The enzyme phosphoglycerate kinase catalyses the phosphorylation of 3-PGA by ATP (which was produced in the light-dependent stage). 1,3-Bisphosphoglycerate (glycerate-1,3-bisphosphate) and ADP are the products. (However, note that two 3-PGAs are produced for every CO 2 that enters the cycle, so this step utilizes two ATP per CO 2 fixed ...
The chemical summation of photosynthesis was a milestone in the understanding of the chemistry of photosynthesis. This was later experimentally verified by Robert Hill. In a nutshell, van Niel proved that plants give off oxygen as a result of splitting water molecules during photosynthesis, not carbon dioxide molecules as thought before.
Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12 C and 1.1% in 13 C. [1] [8] The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. [1]
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants , algae , and cyanobacteria .