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 b6-f complex, Plastocyanin (PC) and
Plastoquinone(PQ) which act as mobile electron carriers
Photosystem I
COMMON FOR BOTH PHOTOSYSTEMS