BIOS 10161 Lecture Notes - Lecture 23: Photosynthetic Reaction Centre, Photosystem I, Electron Transport Chain
18 Nov 2016
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Document Summary
Pigments are arranged in antenna systems, or light harvesting complexes. A photosystem consists of multiple antenna systems and their pigments and surround a reaction center. Pigments are packed together on thylakoid membrane proteins. Excitation energy passes from pigments that absorb short wavelengths to those that absorb longer wavelengths and ends up in the reaction center pigment. Chlorophyll only pigment to give off an electron. Made of 250 -400 pigment molecules rigid antenna complex reaction center -- 2 chlorophyll molecules acts like a radio dish funneling the energy to the reactive center only the 2 chlorophyll molecules in the rxn center give off electrons. The reaction center converts light energy into chemical energy. The excited chlorophyll a molecule (chi*) is a reducing agent (electron donor) A is an acceptor molecule (oxidizing agent), membrane protein of some sort: chi* + a, chi+ + a.
