BIOL 2021 Lecture Notes - Lecture 2: Phosphodiesterase, Calmodulin, Isomerization
11 Mar 2018
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Document Summary
Calcium inside is 10^-7 n outside 10-3 m. Why do cell use ca2+ at an intracellular concentration of 10-7 m for signalling rather than na+ Plasma membrane has na+/ca2+ exchanger, ca2+ pump which uses atp at 10-3 m. Targets could be enymes, membrane transport porteins, protein kinases. Binds to other proteins to activate when calcium is bound. Allows you to change gene concentration levels. Phosphorylate proteins such as gene regulatory proteins on ser/thr. Gproteins regulate ion channels by: binding directly, or indirectly through cycluc nucleotides. Cyclic nucleotides-gates ion channels importat in smell & vision. Light causes change from 11-cis to all trans retinal. Plasma membrane around discs has cgmp gated ion channels. In light: destruction of cgmp, channels close, cell hyperpolarizes, transmitter releases decreases. Stop transmitter release, this sends signals to brain. When rhodophsin absorbs one photon, its activated cgmp molecules are hydrolyzed which causes cation channels to close. Na+ ions are prevented from entering the cell.
