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Methotrexate also indirectly inhibits purine synthesis by blocking the metabolism of folic acid (it is an inhibitor of the dihydrofolate reductase). Allopurinol is a drug that inhibits the enzyme xanthine oxidoreductase and, thus, lowers the level of uric acid in the body. This may be useful in the treatment of gout, which is a disease caused ...
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.
Photosynthesis is a process where light is absorbed or harvested by pigment protein complexes which are able to turn sunlight into energy. [5] Absorption of a photon by a molecule takes place when pigment protein complexes harvest sunlight leading to electronic excitation delivered to the reaction centre where the process of charge separation can take place.
The reaction center contains two pigments that serve to collect and transfer the energy from photon absorption: BChl and Bph. BChl roughly resembles the chlorophyll molecule found in green plants, but, due to minor structural differences, its peak absorption wavelength is shifted into the infrared, with wavelengths as long as 1000 nm. Bph has ...
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.
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C 5 H 4 N 4 O 3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of purine nucleotides, and it is a normal component of urine. [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.