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P680

Definition

noun

The reaction center chlorophyll (or the primary electron donor) of photosystem II that is most reactive and best in absorbing light at wavelength of 680 nm.


Supplement

P680 is a group of pigments that are excitonically coupled or that act as if the pigments are a single molecule when they absorb a photon. It derived its name after the wavelength (in nanometers) at which it is best in capturing. In this case, it is the 680 nm of the electromagnetic spectrum.

P680 is the strongest biological oxidizing agent known at present.


Compare: P700
See also: photosystem II


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Photosynthesis question

... easily find your answers. lights at frequencies of 680 and 700 are best for chlorophylls a and b, hence the names photosystem I and II (P700 and p680), had you the time to look them up. and as for this question.... you are correct, which I thought, but verified with a TEXTBOOK

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by plasmodesmata11
Sun Apr 05, 2009 11:28 pm
 
Forum: Ecology
Topic: Photosynthesis question
Replies: 6
Views: 766

Photosynthesis question

... wiki seems to be correct http://en.wikipedia.org/wiki/Photolysis#Photolysis_in_photosynthesis The process is not carried out by enzymes, but by P680.

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by MrMistery
Sun Dec 28, 2008 11:35 am
 
Forum: Cell Biology
Topic: Photosynthesis question
Replies: 3
Views: 544

Re: photosynthesis

i think C is false, because p680 donats electrons to pq,where as this pq after giving electron to cytochrome(b6f),it accepts proton from the stroma because it dosent have any metal ion just to neutralise/balance it accept protoh from stroma ...

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by pushy
Wed Dec 03, 2008 9:25 am
 
Forum: Molecular Biology
Topic: photosynthesis
Replies: 2
Views: 841

photosynthesis

the false statement is C. Chlorophyll molecules do not donate protons to anything. P680 donates two electrons to the next acceptor in the chain, plastoquinone. Those electrons travel down through the cytochrome chain to plastocianin to eventually rich P700. P700 ...

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by MrMistery
Fri Nov 28, 2008 8:20 pm
 
Forum: Molecular Biology
Topic: photosynthesis
Replies: 2
Views: 841

photosynthesis

... II is false? A. Light energy excites electrons in an antenna pigment in a photosynthetic unit B. The excitation is passes along to a molecule of p680 chlorophyll in the photosynthetic unit C. The p680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+ D. The electron ...

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by mark2399
Fri Nov 28, 2008 3:57 am
 
Forum: Molecular Biology
Topic: photosynthesis
Replies: 2
Views: 841
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