Chapter Chosen

Photosynthesis in Higher Plants

Book Chosen


Subject Chosen


Book Store

Download books and chapters from book store.
Currently only available for.
CBSE Gujarat Board Haryana Board

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12
 Write notes on photosystem I and II.

Photosystem I [PSI] :

Location : It is present in the membrane of stroma thylakoids and non-appressed parts of grana thylakoids.

Pigment molecules : In PS I the reaction centre chlorophyll a which has an absorption peak at P700

Reducing agents : The PS I has following reducing agents viz. ferrodoxin, plastoquinone, cytochrome complex, n-plastocyanin.

Function of PS I : In PS I cyclic photophos-phorylation occurs.

Photosystem II [PS II] :

Location : It is present in appressed part of grana thylakoids.

Pigment molecules : It has in the centre special type of chlorophyll ‘a’ molecules called P680.

Reducing agents : PS II has quencher, plastoquinone, cytochrome complex and plastocyanin reducing agents.

Function : In PS II non-cyclic photophosphorylation occurs, alongwith photolysis of water.



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.

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.

 What is stroma ?

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

Name the first stable compound formed in C3 cycle.

3-phosphoglyceric acid (PGA)

Where CO2 assimilation occurs in CPlants ?

In bundle sheath cells.