Voltage gated calcium channels open when the action

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d. voltage-gated calcium channels open when the action potential depolarizes the cell e. the higher membrane potential turns on a sodium-calcium exchange pump
3.A recording from a patch of membrane measures current through acetylcholine-gated ion channels, which open when acetylcholine is bound. To obtain the recording, acetylcholine was added to the solution in the micropipette (shown in the figure below on the left).
Homework #10_Fall 2015 NAME: ___________________________________ 2 i.What does a current of 2 pA indicate? ii.Why are some of the current readings higher than 2 pA? iii.What would this recording look like if the ACh were in the solution outside the micropipette? 4.You are interested in understanding how the neuromuscular junction works. The normal voltage-gated Na+channel has the characteristics depicted by the solid line in the figure on the next page. You decide to replace this channel with a mutant voltage-gated Na+channel with the characteristics depicted by the dotted line. Do you predict that the cell containing the mutant Na+channel will require more, less, or the same amount or acetylcholine to be released from the nerve terminal to stimulate muscle contraction? Explain your answer.

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