Briefly define the overall function of the light-dependent reactions in photosynthesis and state wherein in the chloroplast castle occur. State the reactants and the assets for the light-dependent reactions. Describe an antenna facility and state the function of the reaction center. Briefly describe the overall duty of Photosystem II in the light-dependent reactions of photosynthesis. Briefly explain how ATP is produced by chemiosmosis throughout the light-dependent reactions of photosynthesis. Briefly explain the overall function of Photosystem i in the light-dependent reactions of photosynthesis. To compare noncyclic photophosphorylation and also cyclic photophosphorylation in regards to Photosystems involved and also products produced.

You are watching: What are the products of linear photophosphorylation?


The exergonic light-dependent reaction of photosynthesis convert light power into chemistry energy, creating ATP and also NADPH. This reactions take place in the thylakoids that the chloroplasts. The products of the light-dependent reactions, ATP and NADPH, are both compelled for the endergonic light-independent reactions.

The light-dependent reactions have the right to be summarized together follows:

\<12\, H_2O + 12\, NADP^+ + 18\, ADP + 18\, P_i + \h\nu \rightarrow 6\, O_2 + 12\, NADPH + 18\, ATP\>

The light-dependent reaction involve 2 photosystems dubbed Photosystem I and also Photosystem II. These photosystems incorporate units called antenna complexes composed of chlorophyll molecules and also accessory pigments situated in the optical membrane membrane. Photosystem ns contain chlorophyll a molecules called P700 since they have actually an absorption peak of 700 nanometers. Photosystem II has chlorophyll a molecules described as P680 due to the fact that they have actually an absorption top of 680 nanometers.

Each antenna facility is may be to trap light and transfer energy to a complex of chlorophyll molecules and proteins called the reaction center (Figure \(\PageIndex1\)). As photons are took in by chlorophyll and also accessory pigments, that energy is eventually transferred to the reaction facility where, when took in by one excitable electron, move it to a higher energy level. Here the electron might be accepted by one electron agree molecule of an electron deliver chain (Figure \(\PageIndex1\)) whereby the light power is converted to chemical energy by chemiosmosis .

*

Figure \(\PageIndex1\): Antenna facility Each antenna facility is may be to trap light and transfer power to a facility of chlorophyll molecules and proteins called the reaction center. Photons are absorbed by chlorophyll and accessory pigments and also that energy is eventually transfered come the reaction center where that is took in by one excitable electron relocating it come a greater energy level. Here the electron deserve to be accepted by an electron agree molecule of one electron transport chain where the light power is convert to chemical power by chemiosmosis

The most usual light-dependent reaction in photosynthesis is called noncyclic photophosphorylation. Noncyclic photophosphorylation entails both Photosystem I and also Photosystem II and produces ATP and NADPH. During noncyclic photophosphorylation, the generation of ATP is combination to a one-way flow of electron from H2O come NADP+. Us will now look at Photosystems I and also II and also their duties in noncyclic photophosphorylation.


1. As photons are took in by pigment molecule in the antenna complexes the Photosystem II, excited electron from the reaction center are picked up by the primary electron acceptor of the Photosystem II electron move chain. Throughout this process, Photosystem II splits molecules of H2O into 1/2 O2, 2H+, and 2 electrons. This electrons continuously replace the electrons being lost by the P680 chlorophyll a molecules in the reaction centers that the Photosystem II antenna complexes (Figure \(\PageIndex2\)).

*

Figure \(\PageIndex2\): number \(\PageIndex2\): Noncyclic Photophosphorylation (1) together photons are soaked up by pigment molecule in the antenna complexes of Photosystem II, excited electron from the reaction center are picked up through the primary electron acceptor of the Photosystem II electron deliver chain. During this process, Photosystem II splits molecules of H2O right into 1/2 O2, 2H+, and also 2 electrons. These electrons continuously replace the electron being lost by the P680 chlorophyll a molecule in the reaction centers the the Photosystem II antenna complexes. (2) during this process, ATP is produced by the Photosystem II electron transfer chain and chemiosmosis. According to the chemiosmosis theory, as the electrons are transported down the electron carry chain, some of the power released is provided to pump protons throughout the optical membrane membrane from the stroma that the chloroplast to the optical membrane interior space producing a proton gradient or proton engine force. As the accumulating protons in the optical membrane interior room pass back throughout the thylakoid membrane to the stroma through ATP synthetase complexes, this proton motive pressure is offered to create ATP indigenous ADP and also Pi. (3) Meanwhile, photons are additionally being soaked up by pigment molecule in the antenna facility of Photosystem I and excited electron from the reaction center are picked up through the main electron agree of the Photosystem i electron deliver chain. The electron being shed by the P700 chlorophyll a molecules in the reaction centers that Photosystem i are changed by the electron traveling under the Photosystem II electron transfer chain. The electron transported under the Photosystem ns electron transfer chain combine with 2H+ from the surrounding medium and also NADP+ to develop NADPH + H+.

During this process, ATP is generated by the Photosystem II electron deliver chain and also chemiosmosis. According to the chemiosmosis theory, together the electrons room transported under the electron deliver chain, several of the energy released is supplied to pump protons throughout the thylakoid membrane native the stroma that the chloroplast come the thylakoid interior an are producing a proton gradient or proton engine force. As the accumulating proton in the thylakoid interior an are pass back throughout the thylakoid membrane to the stroma v ATP synthetase complexes, this proton motive force is offered to generate ATP native ADP and also Pi (Figure \(\PageIndex2\) and also Figure \(\PageIndex3\)).

*

Figure \(\PageIndex3\): Electron Transport and Chemiosmosis throughout Photosynthesis 1. Together photons are soaked up by pigment molecules in the antenna complexes that Photosystem II, excited electron from the reaction center are choose up through the main electron acceptor of the Photosystem II electron move chain. During this process, Photosystem II splits molecules of H2O right into 1/2 O2, 2H+, and 2 electrons. These electrons continuously replace the electron being lost by the P680 chlorophyll a molecules in the reaction centers of the Photosystem II antenna complexes. 2. Throughout this process, ATP is produced by the Photosystem II electron move chain and chemiosmosis. According to the chemiosmosis theory, as the electrons space transported under the electron transfer chain, several of the energy released is provided to pump protons throughout the thylakoid membrane indigenous the stroma of the chloroplast to the optical membrane interior space producing a proton gradient or proton engine force. As the accumulating protons in the thylakoid interior space pass back throughout the thylakoid membrane come the stroma v ATP synthetase complexes, this proton motive force is offered to create ATP from ADP and also Pi. 3. Meanwhile, photons are also being absorbed by pigment molecules in the antenna facility of Photosystem I and excited electron from the reaction center are choose up by the major electron acceptor of the Photosystem i electron move chain. The electrons being lost by the P700 chlorophyll a molecules in the reaction centers the Photosystem ns are changed by the electron traveling down the Photosystem II electron carry chain. The electron transported down the Photosystem i electron deliver chain integrate with 2H+ from the surrounding medium and NADP+ to produce NADPH + H+.


Flash computer animation illustrating the breakthrough of proton motive force as a result of chemiosmosis and also ATP manufacturing by ATP synthase.

See more: Why Are Hurricanes Named After Females Joke, Are Hurricanes With Female Names Deadlier


html5 variation of computer animation for iPad showing the advance of proton motive force as a an outcome of chemiosmosis and also ATP production by ATP synthase.