BIOL 1000 Chapter Notes - Chapter 1: Haloarchaea, Photomorphogenesis, Opsin
15 Dec 2013
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Photon must be transferred to a e- in a molecule, which excites it from the ground state. But, a photon is only absorbed if its energy is equal to the energy difference b/t ground state and excited state. Sun converts hydrogen to helium, converting matter into energy and giving of electromagnetic radiation. For energy to be used by living things, energy must be absorbed. Contains a region where c atoms are covalently bonded w/ea other w/alternating single and dbl bonds. They contain delocalized e-, meaning free electrons that are free to interact with incoming photons. Some organisms use light energy to power proton pumps: halobacteria. The abosorption of a photon causes the retinal to change shape. Shape changes cause changes in opsin, which triggers various other changes. Organisms use eyespots to sense light around them, but not used in photosynthesis. Photoreceptors allow cells to sense light and move away or towards it : photoaxis.
