The resulting flow of protons back into the ..

The excitation energy trapped by a reaction center provides the energy needed for electron transfer, which is the next step in the photosynthetic light reactions. During electron transfer, individual electrons are removed from water molecules and transferred, by an electron transport chain, to NADP+ . Electron transport in photosynthesis is like electron flow in an electric circuit driven by a battery. The voltage difference across the battery pushes electrons through the circuit, and the electron current can be used to do work. In photosynthesis, light energy pushes electrons up an energy hill in the reaction centers. Subsequent electron flow in the electron transport chain is energetically downhill and can be used to do work. Figure 2 shows the electron carriers that make up the photosynthetic electron transport chain in a way that reveals the relative electronic energy on the vertical scale. This is known as the Z-scheme. Note that a negative voltage corresponds to a higher energy, so that downhill electron flow is from the top to the bottom of the figure.

flow of electrons during photosynthesis? | Yahoo Answers

22/02/2014 · The kinetic energy from the flow of protons is ..

01/01/2008 · Flow of electrons during photosynthesis

We have seen how ATP synthase acts like a proton-powered turbine, and uses the energy released from the down-gradient flow of protons to synthesize ATP. The process of pumping protons across the membrane to generate the proton gradient is called . Chemiosmosis is driven by the flow of electrons down the electron transport chain, a series of protein complexes in the membrane that forms an electron bucket brigade. Each of these protein complexes accepts and passes on electrons down the chain, and pumps a proton across the membrane for each electron it passes on. Ultimately, the last complex in the electron transport chain passes the electrons to molecular oxygen (O2) to make water, in the case of aerobic respiration.

in that the flow of protons down ..

This proton gradient is analogous to water stored in an elevated reservoir. The higher the water level in the reservoir, the more potential energy is available to accomplish mechanical work like turning a water wheel to grind grain. In the same way, the greater the difference in proton concentrations across the membrane, the more energy is available for ATP synthase to make ATP. Indeed, the ATP synthase complex even resembles a water wheel, in that the flow of protons down their concentration gradient, through ATP synthase, causes a part of ATP synthase to rotate.


What is uncoupling in photosynthesis? - Quora

Through the process of photosynthesis, plants harness the sun's energy and in so doing make many forms of life—including human life—possible.
How photosynthesis starts and fuels the flow of energy through all life.

23/09/2016 · What is uncoupling in photosynthesis ..

Plants also convert energy from light into chemical energy.
Photosynthesis and respiration are Electrochemical gradient creates energy that the protons use to flow "Photosynthesis vs Cellular Respiration.".
Photosynthesis energy flow chart further difference between anabolism and catabolism as well as cellular respiration flow chart in addition flow of energy.

Photosynthesis and energy in nature - from Flying …

The reaction is energetically uphill and is driven by the transmembrane proton electrochemical gradient. The ATP synthase enzyme is a molecular rotary motor. Protons move through a channel in the ATP synthase protein (from the inner water phase to the outer water phase of the vesicle) providing the energy for ATP synthesis. However, the protons are not involved in the chemistry of adding phosphate to ADP at the catalytic site. Although it has not been proven, it appears that proton flow drives the rotation part of the ATP synthase at rates as high as one hundred revolutions per second (Figure 4). The rotation of ATP synthase can be thought of as pushing ADP and Pi together to form ATP and water.

Plant Energy Transformations-Photosynthesis - …

Most of the energy from the electron transfer reactions is stored as redox energy in NADPH as described above. However, some of the energy is stored across the membrane of the photosynthetic vesicle in the form of a pH gradient (or protein gradient) and an electric potential (positive inside). As previously noted, the electron transport chain concentrates protons in the inner water phase of the vesicle by the release of protons during the oxidation of water by Photosystem II and by transporting protons from the outer water phase to the inner water phase via plastoquinone (Figure 3). In addition, electron transport creates a net positive charge on the inner side and a net negative charge on the outer side of the vesicle, which gives rise to an electric potential across the membrane. The energy stored in the pH gradient and electric potential is known as the transmembrane proton electrochemical potential or the proton motive force.

The Light-Dependent Reactions of Photosynthesis

In plants essentially all electron flow from water follows the pathway shown in Figure 3, at least up to ferredoxin. However, once an electron reaches ferredoxin the electron pathway becomes branched, enabling a fraction of the redox free energy to enter other pathways, including cycling through the Photosystem I reaction center. Photosystem I cyclic electron transport provides additional energy for ATP production, which allows plants to adjust the energy flow according to their metabolic needs.