LIFE SCIENCE

Detailed explanation-1: -Both photosystems contain many pigments that help collect light energy, as well as a special pair of chlorophyll molecules found at the core (reaction center) of the photosystem. The special pair of photosystem I is called P700, while the special pair of photosystem II is called P680.

Detailed explanation-2: -The primary electron donor of photosystem I, P700, is a chlorophyll species that in its excited state has a potential of approximately-1.2 V.

Detailed explanation-3: -At the heart of photosynthetic reaction centers (RCs) are pairs of chlorophyll a (Chla), P700 in photosystem I (PSI) and P680 in photosystem II (PSII) of cyanobacteria, algae, or plants, and a pair of bacteriochlorophyll a (BChla), P870 in purple bacterial RCs (PbRCs).

Detailed explanation-4: -The two photosystems are Photosystem I and Photosystem II. Both these photosystems PS I and PS II are multi-subunit membrane-protein complexes participating in oxygenic photosynthesis. The pigment that is mainly involved in trapping light energy is chlorophyll. Thus, it is called a pigment system or photosystem.