non cyclic photophosphorylation

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Erised
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non cyclic photophosphorylation

Post by Erised » Fri Nov 25, 2005 4:42 pm

Hey.

I'm studying non cyclic electron flow right now. After many hours it's finally clear in my head :shock: but I don't understand one thing.
In my book it sayd that in step 3, a water molecule is being split to two electrons, two hydrogen ions, and one oxygen atom
Electrons are passed to PSI and p700, while the oxygen atom combines with another oxygen atom to form O2 ->thus this is where oxygen comes from

but what happens to the two hydrogen ions? My book doesn't say what and I can't find anything on the internet. The only logical explanation is that it is passed to NADP+ along with electrons, which reduces to NADPH. AM I right? If not, where does the hydrogen go???

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MrMistery
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Post by MrMistery » Fri Nov 25, 2005 9:59 pm

you are partially right. H+ is used later to produce NADPH, but the hidrogen ions are firstly used to create a gradient(the gradinent is created also by the kynetic energy of electrons) and later to make ATP. Remember that the second fase of photosynthesys(NOT TO BE CALLED LIGHT INDEPENDENT!!!) uses ATP as well as NADPH
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

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