A proton pump is an integral ..

H+/ATPase proton pump. The pump is required for stomatal opening (see above).
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The energy required for the proton pumping ..

The energy budget of a plant depends upon the ratio of protons pumped across the thylakoid membrane to electrons passed through photosynthetic electron transfer complexes (the H+/e ratio), which sets the stoichiometries of ATP and NADPH production for use in the Calvin–Benson cycle and other biochemical pathways (reviewed in refs. and ). There has been a long-standing debate about the magnitude of H+/e for green plant photosynthesis, particularly regarding the proton pumping reactions of the cytochrome (cyt) b6f complex. It is generally accepted (see review in ref. ) that for each electron transferred through the linear pathway, one proton is released into the lumen at the level of water splitting; another is transported across the thylakoid membrane by the reduction and reoxidation of plastoquinone (PQ) at the photosystem II (PSII) QB site and the cyt b6f complex Qo site, respectively; and a third proton is pumped, at least under some conditions, by the turnover of a Q cycle associated with the oxidation of plastoquinol at the cyt b6f complex (see refs. – for reviews).

There are two mechanisms by which water loss regulates stomatalclosure, one of which is active and the other passive.
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Chapter 24 Electrogenic Reactions and Proton Pumping …

Electron transfer flux through PSII was estimated by the saturation pulse fluorescence rise technique introduced by Genty et al. (). The application of supersaturating pulses of light saturates all photochemical reaction centers, and changes in chlorophyll a fluorescence yield reflect the photochemical quantum efficiency of PSII-associated antenna (II; e.g., ref. ). Multiplying II by the absorbed actinic light intensity has been shown to yield a good estimate of photosynthetic electron transfer rates (see e.g., refs. , –). In the present work, we multiplied II by the incident light intensity (the product being denoted iII), which provides, in arbitrary units, a measure of PSII electron flux.

Cytochrome b6f: Proton Pumping and ATP Synthesis - …
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As they travel along the ETC they give up energy which is used to pump the protons into the thylakoid space
More protons in the thylakoid space than stroma
The proton pump is used mostly in chemiosmosis
Proton Pumps:
Thylakoid membranes produce ATP and NADPH
Electrons move through sequential molecular complexes within the thylakoid membrane and the one passes electrons to NADP+ and turns into NADPH
The carrier at the start of the electron transport chain (ETC) pumps hydrogen ions (referred to as protons in this case) from the stroma into the thylakoid space
The hydrogen ions then flow out of the space back into the stroma through ATP synsthase and ATP is produced
Proton Pumps:
A proton pump is a protein complex that moves protons during oxidation reactions across a membrane

Evolution of proton pumping ATPases: Rooting the …
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Cytochrome b6f: Proton Pumping and ATP Synthesis - YouTube

Cyclic Electron Flow - Occurs when ATP is lacking (since more ATP is used in the Calvin cycle than NADPH).
- No NADPH is produced because the electron involved in the cycle does not go to NADPH Reductase.

1) An electron from Photosystem I is excited and is transferred to the cytochrome complex, where an H+ is pumped into the lumen and adds to the proton gradient.
2) The electron returns to Photsystem I and the cycle repeats.
3) Meanwhile, the proton gradient allows for the synthesis of ATP at ATP Synthase.

Photosynthesis Flashcards | Quizlet

Fates of G3P:
- 2 G3P make glucose.
- Glucose can be used to produce starch (energy storage), cellulose (cell walls) and sucrose.
- 1 G3P can also be converted to a pyruvate molecule which then goes through cellular respiration in the mitochondria.
- Through complex processes, G3P can be used to produce nucleic acids, proteins, fatty acids and tri-glycerides.

photosynthesis in living plants: A proton-pumping Q cycle is ..

2 Stages of Photosynthesis:
1) Light-Dependent reactions
2) Calvin Cycle (Light-Independent reactions 1) Light-Dependent Reactions Begins at Photosystem II - sunlight excites an electron, and it is transferred to the cytochrome Plastoquinone and then to Plastocyanin.

The proton‐pumping respiratory complex I of bacteria …

(a) provides sugars (sucrose and glucose) for osmotic regulation; (b) provides ATP (via photophosphorylation) to power ion pumps (see below); (c) reduces internal CO2 levels which stimulates opening (see below); and (d) reduces the pH in the lumen of the thylakoid that stimulates the synthesis of the blue light receptor pigment (see below).