Search results
Results from the WOW.Com Content Network
Ferredoxin: NADP + reductase is the last enzyme in the transfer of electrons during photosynthesis from photosystem I to NADPH. [2] The NADPH is then used as a reducing equivalent in the reactions of the Calvin cycle. [2] Electron cycling from ferredoxin to NADPH only occurs in the light in part because FNR activity is inhibited in the dark. [11]
The NADPH system is also responsible for generating free radicals in immune cells by NADPH oxidase. These radicals are used to destroy pathogens in a process termed the respiratory burst. [13] It is the source of reducing equivalents for cytochrome P450 hydroxylation of aromatic compounds, steroids, alcohols, and drugs.
This is the second core process in photosynthesis. The initial stages occur within picoseconds, with an efficiency of 100%. The seemingly impossible efficiency is due to the precise positioning of molecules within the reaction center. This is a solid-state process, not a typical chemical reaction. It occurs within an essentially crystalline ...
Photosystem I operates with the functions of producing NADPH, the reduced form of NADP + (Fd 2-red + NADH + 2 NADP + + H + = Fd ox + NAD + + 2 NADPH.), at the end of the photosynthetic reaction through electron transfer, and of providing energy to a proton pump and eventually ATP, for instance in cyclic electron transport.
In contrast, the main function of NADPH is as a reducing agent in anabolism, with this coenzyme being involved in pathways such as fatty acid synthesis and photosynthesis. Since NADPH is needed to drive redox reactions as a strong reducing agent, the NADP + /NADPH ratio is kept very low.
In general outline, photosynthesis is the opposite of cellular respiration: while photosynthesis is a process of reduction of carbon dioxide to carbohydrates, cellular respiration is the oxidation of carbohydrates or other nutrients to carbon dioxide. Nutrients used in cellular respiration include carbohydrates, amino acids and fatty acids.
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the energy-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria.
The main role of these is to transport hydrogen atom to electron transport chain which will change ADP to ATP by adding one phosphate during metabolic processes (e.g. photosynthesis and respiration). Hydrogen carrier participates in an oxidation-reduction reaction [ 2 ] by getting reduced due to the acceptance of a Hydrogen.