LIFE 102 Lecture Notes - Light-Independent Reactions, Photosystem Ii, Photosynthetic Reaction Centre
Document Summary
A photosystem: a reaction-center complex associated with light-harvesting complexes. A photosystem consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes. The light-harvesting complexes (pigment molecules bound to proteins) funnel the energy of photons to the reaction center. A primary electron acceptor in the reaction center accepts an excited electron from chlorophyll a. Solar-powered transfer of an electron from a chlorophyll a molecule to the primary electron acceptor is the first step of the light reactions. There are two types of photosystems in the thylakoid membrane. Ps ii is best at absorbing a wavelength of 680 nanometers. The reaction-center chlorophyll a of ps ii is called p680. Ps i is best at absorbing a wavelength of 700 nm. The reaction-center chlorophyll a of ps i is called p700. During the light reactions, there are two possible routes for electron flow: cyclic and linear. Linear electron flow, the primary pathway, involves both photosystems and produces.
