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Photosynthesis in Higher Plants

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

What is photosystem ? Which is the pigment that acts as reaction centre ? Describe the interaction of photosystem I and photosystem II.

 


Photosystem : It is a group of pigment molecules and electron acceptors which take part in oxidation and reduction reaction in photosynthesis for producing ATP and NADPH.

Reaction Centre : Chla molecules  act as reaction centres. The Chla of speacial types form different reaction centres like P680 in PS II and P700 in PS I.

Interaction of PS I and PS II :

PS I and PS II are interlinked in following two

ways :

Ist way : P680 reaction centre of PS II takes energy from sunlight. Then, it emits electron which pass through number of electron acceptors and then go to P700, a reaction centre of PSI.

IInd way : The P700 takes energy from sunlight via harvesting molecule and its electron is emitted. This electron passes through primary acceptor x and then to ferrodoxin and after this to NADP reductase.

During photolysis of H2O, the H2O splits into H+ and OH. The OH changes into H2O, O2 and electrons are released which go to P680 molecule. The H+ goes to NADP reductase which combines NADP, H+ and e form assimilatory power called NADPH

What is photosystem ? Which is the pigment that acts as reaction centre ? Describe the interaction of photosystem I and photosystem II.
Or
Discuss the mechanism of oxidation-reduction occurring in photosynthesis to generate ATP and NADPH.

329 Views

Where CO2 assimilation occurs in CPlants ?

In bundle sheath cells.
766 Views

 What is stroma ?

Stroma is matrix or the cytoplasm of chloroplast where dark reaction of photosynthesis takes place.
783 Views

Why Rubisco is not affected by O2 in C4 plants ?

O2 is formed in mesophyll cells while Rubisco is present in bundle sheath cells. Therefore Rubisco does not come in contact with O2 and is thus not affected by it.
710 Views

Name the first stable compound formed in C3 cycle.

3-phosphoglyceric acid (PGA)
1606 Views

What are grana ?

Grana are the stacks of thylakoids embedded in the stroma of a chloroplast. They are the sites of light reaction of photosynthesis.
842 Views