You discover a new organism living at the bottom of a very deep, unexplored cave. you characterize its nervous system by the finding the nernst potentials and permeabilities to the major ions in/around the neurons. the data is summarized in the table below.
equilibrium potential
permeability
be2+
-60 mv
1
li+
10 mv
0.1
(2 pt) how would you expect the resting potential to change if the permeability to li+ was increased ten-fold (more positive, more negative, no large change)? explain your answer.
(1 pt) you add a drug that blocks be+2 channels and causes the permeability of be+2 to decrease to 0. what is the new resting potential of the neuron.
(2 pt) is there any net flow of ions at the resting potential in part ‘b’ above? why or why not?
(2 pt) you discover that there are also rb+ ions present at the same intracellular and extracellular concentrations as the be+2 ions (although there are no channels for the rb+ ions to pass through). what would the nernst potential of rb+ be if there were channels for it? explain your thinking.
(1 pt) assume that the resting potential of the neuron is -40 mv. you are conducting a voltage clamp experiment, and decide to depolarize the membrane by 25 mv. what is the new membrane potential?