BIOL 2021 Lecture Notes - Lecture 13: Signal Transduction, Radio Television Of Kosovo, Rhodopsin
11 Oct 2012
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Document Summary
G- protein regulated ion channels binding directly or indirectly through cyclic nucleotide. The outer segment contain the stuff that interact with the sunlight. The retina is an extention of the brain send signals. Photoreceptors = is a protein called rhodopsin this is a g-protein photoreceptor. All trans-retinal all the double bonds are trans. Retinal absorbs the light and changes the receptor conformation this is due to the fact that there is an isomerasization of retinal. It goes from 11 cis to all trans in the double bonds. The activated receptor is now going to cause a change in the g-protein. The g-protein is called g_+ called transducin this activates cyclic gmp phosphodiesterase. The cgmp is made by guanylyl cyclase which is destroyed by cgmp phosphodiesterase. In the dark there is high cgmp ion channels open. The cell is depolarized releasing transmitter at a high rate. It seems that there is a high rate of the transmitter.
