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Cytochrome b 6 f and ATP synthase work together to produce ATP (photophosphorylation) in two distinct ways. In non-cyclic photophosphorylation, cytochrome b 6 f uses electrons from PSII and energy from PSI [citation needed] to pump protons from the stroma to the lumen. The resulting proton gradient across the thylakoid membrane creates a proton ...
ATP synthase is an enzyme that catalyzes the formation of the energy storage molecule adenosine triphosphate (ATP) using adenosine diphosphate (ADP) and inorganic phosphate (P i). ATP synthase is a molecular machine. The overall reaction catalyzed by ATP synthase is: ADP + P i + 2H + out ⇌ ATP + H 2 O + 2H + in
ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to convert phosphorylate adenosine diphosphate (ADP) into ATP. The ATP synthase contains two parts: CF0 (present in thylakoid membrane) and CF1 (protrudes on the outer surface of thylakoid membrane).
ATP synthase is composed of two linked multi-subunit complexes: the soluble catalytic core, F1, and the membrane-spanning component, Fo, comprising the proton channel. The catalytic portion of mitochondrial ATP synthase consists of 5 different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alpha, 3 beta ...
Both the structure of ATP synthase and its underlying gene are remarkably similar in all known forms of life. ATP synthase is powered by a transmembrane electrochemical potential gradient, usually in the form of a proton gradient. In all living organisms, a series of redox reactions is used to produce a transmembrane electrochemical potential ...
ATP synthase produces 1 ATP / 3 H +. However the exchange of matrix ATP for cytosolic ADP and Pi (antiport with OH − or symport with H +) mediated by ATP–ADP translocase and phosphate carrier consumes 1 H + / 1 ATP as a result of regeneration of the transmembrane potential changed during this transfer, so the net ratio is 1 ATP : 4 H +.
F-type proton ATPase [12] [13] (or F-ATPase) typically operates as an ATP synthase that dissipates a proton gradient rather than generating one; i.e. protons flow in the reverse direction compared to V-type ATPases. In eubacteria, F-type ATPases are found in plasma membranes.
The energy resulting from the flux of protons back into the matrix is used by ATP synthase to combine inorganic phosphate and ADP. [6] [2]: 743–745 Similar to the electron transport chain, the light-dependent reactions of photosynthesis pump protons into the thylakoid lumen of chloroplasts to drive the synthesis of ATP. The proton gradient ...