1)Question 1 (20 pts) You are studying neurons in the lab by growing them in culture (in a petri dish outside the body). You grow them in an incubator at 37 degrees C. With this experimental setup, you can easily change the extracellular ion concentrations by switching the cell culture medium (the fluid that surrounds the cells).
|Intracellular concentration||Medium 1(extracellular concentration)||Medium 2(extracellular concentration)|
|K+||140 mM||4.5 mM||50 mM|
|Na+||10 mM||135 mM||100 mM|
|Cl-||12 mM||125 mM||120 mM|
a.(1pt) If you switch from Medium 1 to Medium 2 will the intracellular concentrations change? Briefly explain your answer.
c.(5 pts) C
d. (1 pt) In Medium 1, which ion has the largest driving force at rest, and what is its driving force?
e.(2 pts) What do you predict will happen to the membrane potential if the relative permeability of potassium:sodium:chloride changes to 100:200:5 No calculation needed, just explain your thinking.
f.(3 pts) In Medium 1, if we voltage clamp the cell at -100 mV, which direction will each ion move if the cell becomes suddenly highly permeable to that ion For each ion, write 1 sentence to explain what is happening.