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Chemiosmosis is the movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient.An important example is the formation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H +) across a membrane during cellular respiration or photosynthesis.
This transport chain produces a proton-motive force, pumping H + ions across the membrane and producing a concentration gradient that can be used to power ATP synthase during chemiosmosis. This pathway is known as cyclic photophosphorylation, and it produces neither O 2 nor NADPH.
In cyclic photophosphorylation, cytochrome b 6 f uses electrons and energy from PSI to create more ATP and to stop the production of NADPH. Cyclic phosphorylation is important to create ATP and maintain NADPH in the right proportion for the light-independent reactions. The net-reaction of all light-dependent reactions in oxygenic photosynthesis ...
Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis. The electron transport chain in the cell is the site of oxidative phosphorylation. The NADH and succinate generated in the citric acid cycle are oxidized, releasing the energy of O 2 to power the ATP synthase.
This reflux releases free energy produced during the generation of the oxidized forms of the electron carriers (NAD + and Q) with energy provided by O 2. The free energy is used to drive ATP synthesis, catalyzed by the F 1 component of the complex. [13] Coupling with oxidative phosphorylation is a key step for ATP production.
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
The Calvin cycle uses the chemical energy of ATP and the reducing power of NADPH from the light-dependent reactions to produce sugars for the plant to use. These substrates are used in a series of reduction-oxidation ( redox ) reactions to produce sugars in a step-wise process; there is no direct reaction that converts several molecules of CO 2 ...
The energy derived from the pumping of protons across a cell membrane is frequently used as the energy source in secondary active transport. In humans, sodium (Na + ) is a commonly cotransported ion across the plasma membrane, whose electrochemical gradient is then used to power the active transport of a second ion or molecule against its ...