Photosystems i and ii

Describes Photosystem I and II or Pigment systems which help in the trapping and utilizing solar energy for electron transport chain

1. PHOTOSYSTEMS I AND II Dr. K. Kannathasan A.P.A. College of Arts & Culture, Palani

2. Photosystem I PHOTOSYSTEMS Photosystem II Absorbs light longer than 680mµ Absorbs light shorter than 680mµ P700 is the reaction centre P680 is the reaction centre P680 is a special form of chl -a that absorb light at 680 mµ P700 is a special form of chl -a that absorb light at 700mµ

3. Photosystem II Weakly fluorescent   Strongly fluorescent Pigments chlorophyll- b and different types/forms of chlrophyll a namely chl -a (670mµ), chl -a (680mµ), chl -a (677mµ), chl -a (692mµ ) and carotenoids   Pigments chl -b and some forms of chlrophyll a such as chl -a (662mµ), chl -a (670mµ), chl -a (677mµ)and carotenoids   The pigment systems contain a central core complex called as light harvesting complex (LHC). The LHC contains reaction centers associated with proteins, electron donors and electron acceptors. The Photosystem I and Photosystem II are interconnected by cytochrome b 6 -f complex , Plastocyanin (PC) and Plastoquinone (PQ) which act as mobile electron carriers Photosystem I COMMON FOR BOTH PHOTOSYSTEMS