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Quantasomes are particles found in the thylakoid membrane of chloroplasts in which photosynthesis takes place. They are embedded in a paracrystalline array on the surface of thylakoid discs in chloroplasts. They are composed of lipids and proteins that include various photosynthetic pigments and redox carriers.
The thylakoid membranes of higher plants are composed primarily of phospholipids [5] and galactolipids that are asymmetrically arranged along and across the membranes. [6] Thylakoid membranes are richer in galactolipids rather than phospholipids; also they predominantly consist of hexagonal phase II forming monogalacotosyl diglyceride lipid.
Electrons travel through the cytochrome b6f complex to photosystem I via an electron transport chain within the thylakoid membrane. Energy from PSI drives this process [ citation needed ] and is harnessed (the whole process is termed chemiosmosis ) to pump protons across the membrane, into the thylakoid lumen space from the chloroplast stroma.
Photosystem I [1] is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the moderate-energy hydrogen carrier NADPH . [ 2 ]
The reaction center is in the thylakoid membrane. It transfers absorbed light energy to a dimer of chlorophyll pigment molecules near the periplasmic (or thylakoid lumen) side of the membrane. This dimer is called a special pair because of its fundamental role in photosynthesis.
It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol.
Electron transfer reactions in the thylakoid membranes are complex, however, and the source of electrons used to reduce P700 + can vary. The electron flow produced by the reaction center chlorophyll pigments is used to pump H + ions across the thylakoid membrane, setting up a proton-motive force a chemiosmotic potential used mainly in the ...
Plastoquinone (PQ) is a terpenoid-quinone (meroterpenoid) molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis.The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4-benzoquinone molecule with a side chain of nine isoprenyl units.