How does NADP get reduced to NADPH in the light dependent reaction?

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F1's Finest
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#1
Report Thread starter 9 years ago
#1
Is it by the protons from the photolysis of water?

Or is it by both, the electrons from the e- transport chain and the protons from the photolysis of water.


In an exam question it says, describe how NADP is reduced in the light dependent reaction.

The answer is that;

It is reduced by electrons, from the photolysis of water.

Which I think is wrong
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DavidYorkshireFTW
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#2
Report 9 years ago
#2
Yes, it is both the electrons from the electron transport chain, which have lost the majority of their energy to synthesise ATP, and also the Hydrogen ion (H^+) from the photolysis of water, which bind to the NADP to form reduced NADP
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Dr00n
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#3
Report 9 years ago
#3
I THINK that the NADP is reduced when it acts as the final electron (proton) acceptor in the stroma surrounding the thylakoid membrane. As it acts hydrogen during the process of ATP synthesis as H+ ions are moved through atp synthase by chemiosmosis.
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Pride
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#4
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#4
(Original post by James A)
Is it by the protons from the photolysis of water?

Or is it by both, the electrons from the e- transport chain and the protons from the photolysis of water.


In an exam question it says, describe how NADP is reduced in the light dependent reaction.

The answer is that;

It is reduced by electrons, from the photolysis of water.

Which I think is wrong
yea, my textbook would disagree with that answer too.
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Dr00n
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#5
Report 9 years ago
#5
but it is reduced by electrons.

NADP is defined as the final electron acceptor in photophosphorylation. The 2 electrons produced in the photolysis of water replace the 2 electrons lost in Photosystem 2, and are used to reduce NADP
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byebyebadman
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#6
Report 9 years ago
#6
Thought I'd ask a question here rather than start a new thread:

Is reduced NADP the same as NADPH? My (aqa) syllabus speaks of reduced NADP, however I have always used the term NADPH. Will this be accepted by my examiners in place of reduced NADP?

And as for the old original OP question.......my understanding is that NADP itself is positive, with a charge of +1. When sunlight releases electrons from chloroplasts, a pair of electrons are picked up by a molecule of NADP, which would give it a -1 charge. It therefore picks up a proton to become NADPH. (the protons have been generated from the photolysis of water) The electrons produced by the photolysis of water replace those that were excited from the chloroplasts, thus enabling the process to continue.
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byebyebadman
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#7
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#7
Anyone?
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DavidYorkshireFTW
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#8
Report 9 years ago
#8
(Original post by byebyebadman)
Anyone?
I think NADPH is reduced NADP, which is what takes thes the electrons to the light independent stage or something, i think Can't really remember
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Ben_Saahil
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#9
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#9
Yea I think reduced NADP is the same as NADPH. One is a short way of writing it. But am not too sure.
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Macdeez44
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#10
Report 1 year ago
#10
HI, energy is required to reduce the NADP, energy that is sourced from the electron transport chain, Additionally electrons are required to reduced NADP which are sourced from the photolysis of water which also uses the energy from the electron transport chain
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