Biology 1002B Lecture Notes - Lecture 2: Photoisomerization, Radiography, Electron Transport Chain
1 May 2013
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Document Summary
The energy of the life is inversely related to the wavelength. Has to take energy of the photons and trap the energy in a molecule. Pigments have a conjugated system: double bond, single bond, double bond, etc. Represent an abundance of electrons that are non-bonding pi orbital electrons. Readily available to be excited by a photon of light; ready to trap the light. Retinal is one exception where the electrons are non-bonding. Pigments aren"t free in the cell, it"s bound non-covalently to proteins to form pigment-protein complexes. After centrifugation, you can see proteins stay attached to pigments. Ground state; lower excited state; higher excited state. One photon can excite one electron; photochemical equivalence. 4 fates of excited state that are competing processes. Heat loss: decays back to ground state. Lose just a little energy as heat, and get to a sub-excited state, and lose the rest as fluorescence.
