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This word is taken from two Greek words, photos, which means light, and synthesis, which in chemistry means making a substance by combining simpler substances. So, in the presence of light, synthesis of food is called 'photosynthesis'. Noncyclic photophosphorylation through light-dependent reactions of photosynthesis at the thylakoid membrane.
In chemistry, many reactions depend on the absorption of photons to provide the energy needed to overcome the activation energy barrier and hence can be labelled light-dependent. Such reactions range from the silver halide reactions used in photographic film to the creation and destruction of ozone in the upper atmosphere .
The light-harvesting complex (or antenna complex; LH or LHC) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants and cyanobacteria, which transfer light energy to one chlorophyll a molecule at the reaction center of a photosystem.
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.
Reaction centers are present in all green plants, algae, and many bacteria.A variety in light-harvesting complexes exist across the photosynthetic species. Green plants and algae have two different types of reaction centers that are part of larger supercomplexes known as P700 in Photosystem I and P680 in Photosystem II.
Chlorophyll a is very important in the energy phase of photosynthesis. Two electrons need to be passed to an electron acceptor for the process of photosynthesis to proceed. [5] Within the reaction centers of both photosystems there are a pair of chlorophyll a molecules that pass electrons on to the transport chain through redox reactions. [20]
Location of the psa genes in the chloroplast genome of Arabidopsis thaliana.The 21 protein-coding genes involved in photosynthesis are displayed as green boxes. Photosystem I (PSI, or plastocyanin–ferredoxin oxidoreductase) is one of two photosystems in the photosynthetic light reactions of algae, plants, and cyanobacteria.
In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plants using Chlorella. Chlorella has been considered as a source of food and energy because its photosynthetic efficiency can reach 8%, [ 3 ] which exceeds that of other highly ...