BIO304H5 Lecture Notes - Lecture 11: Calcium Signaling, Lysine, Cyclic Adenosine Monophosphate
Document Summary
Slide 4: the ap happens very fast. It just happens that at rest, the driving force is for sodium to go in and potassium to go out. Slide 9: based on the ap, the main players are potassium and sodium channels. Selectivity filter: says that says this filter is selected for potassium. It was by virtue of a duplication: these are leak potassium channels, they are always open, this duplication is in eukaryotes, not likely to happen in bacteria. Slide 13: maybe the voltage sensor evolved on its own in bacteria. Somewhere on the way, the voltage sensor used the pore loop channel rendering its own conductance irrelevant, it is now become purely a sensor of voltage: the voltage sensor could now be used to open the pore. Some indirect evidence that this is true comes from diseases because there are several diseases in voltage-gated ion channels in the sensor that make them permeable to ions.
