Pigment System I And Pigment System II

Differences between Pigment System I and Pigment System II

Pigment System I (PS I)Pigment System II (PS II)
PS I is made up of about 200 to 400 chlorophyll molecules;

 

50 carotenoid molecules; one molecule of reaction centre P700 (Chl.a700), Plastocyanin, Cytochrome f each; two molecules of Cyt. b563 (Cyt b6) and one or 2 molecules of ferredoxin.

PS II is made up of about 200 chlorophyll molecules;

 

50 carotenoid molecules; one molecule of reaction centre P680 (Chl. a680), and other substances Z, Mn++, Cl-, Quinone, Cytochrome b6 (b559), Cytochrome f and Plastocyanin each.

2. Usually the number of Chl. b. molecules is less.2. Usually the number of Chl. b molecules is more.
3. It’s reaction centre is P7003. Its reaction centre is P680.
4. It is located on the outer surface of the thylakoid.4. It is located on the inner surface of the thylakoid.
5. In this system, molecular O2 is not evolved.5. In this system, molecular O2 is evolved as a result of the breakdown of water.
6. Pigment System I formed NADPH + H+.6. NADPH + H+ is not formed in PS II.
7. It participates in both cyclic and non-cyclic photophosphorylation.7. It participates only in non-cyclic photophosphorylation. It gives elections to PS I when NADP is reduced to. NADPH + H+ in PS I.
8. When chloroplasts are ultracentrifuged, PS I being lighter comes up. Thus, PS IBcomes under a lighter fraction.8. On ultracentrifugation, PS II being heavier settles down. Thus PS II comes under a heavier fraction.