Practice question · Sort into groups
Sort each ion by where it is more concentrated across the membrane of a resting neuron.
Groups: More concentrated OUTSIDE · More concentrated INSIDE
- Cl- (chloride)
- K+ (potassium)
- A- (large organic anions)
- Na+ (sodium)
Hints
- Two ions are kept high outside and two high inside - the pump and trapped anions maintain the split.
- Potassium and the big organic anions are the inside pair; sodium and chloride are the outside pair.
Show the answer
More concentrated OUTSIDE: Na+ (sodium), Cl- (chloride)
More concentrated INSIDE: K+ (potassium), A- (large organic anions)
Why
Na+ and Cl- are concentrated outside; K+ and the impermeant organic anions (A-) are concentrated inside. These standing gradients are the stored energy the neuron later spends when it fires - not an accident but an actively held arrangement.
Practise Resting Potential
The app has 5 more questions on this lesson, and keeps your place in the course. Psychology I is free to start.
More questions on Resting Potential
- A neuron at rest sits at about −70 mV. Why is the membrane NOT electrically neutral at rest?
- Trace WHY the inside of the resting neuron ends up negative. Put the causal steps in order.
- A neuron's potassium equilibrium potential is about −90 mV, yet the membrane actually rests at about −70 mV.…
- Select every statement that is TRUE of the resting potential.
- The sodium-potassium pump runs constantly in every neuron, and the brain spends a large share of its entire…