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 P700||3. 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.|