Question

define reaction centre

Answer 1

Reaction centre is a term used for a complex of several proteins, pigments and other co-factors assembled together to execute the primary energy conversion reactions of photosynthesis. Here, primary electron transfer takes place. Reaction centre has a single chlorophyll a molecule. It also collects light from light harvesting complexes also. The reaction centre is different in both the photosystems. In PS I the reaction centre chlorophyll a has an absorption peak at 700 nm, hence is called P700, while in PS II it has absorption maxima at 680 nm, and is called P680.