Answer Happy

This worksheet is intended to help you grasp the concept of membrane potential, using the ions that play a large role in setting up the membrane potential. Remember that all cells have a membrane potential, although we will be focusing our attention on neurons. Shown below is a simple MODEL of a cell membrane with the ions we most care about-there are ions that are adjacent to the plasma membrane (small squares), but the cell also has larger stores of these ions inside and outside the cell. OUT 1. What is the membrane potential (mv) of this cell? Explain. Let's focus on the K*ions and the K* leak channels, which are always open. What happens now ?? 2. Which of the pictures below demonstrate the best representation of what will happen? Will only small amounts of K* move or will large amounts of K* move to the outside? Explain your answer considering both the chemical/concentration gradient of K", but also the electrical gradient of K". A B с

Now let's take a look at both Na/K* ions. There are Nat leak channels, but very few in comparison to k channels. OUT கல 3. Which of the following pictures best represent a resting potential of a neuron? Explain your answer. B. A с

the phases of the action potential that are represented by the letters in the figure below. Membrane potential (mV) LA B -55 70- 2 Time (msec) 5. Which part of the figure above corresponds to: A. A time when voltage-gated sodium channels are inactivated, then reset to the closed state. Potassium channels continue to open. B. A time when voltage-gated sodium and potassium channels are closed. C. A time when voltage-gated sodium channels begin to inactivate, and voltage-gated potassium channels begin to open D. A time when some voltage-gated potassium channels remain open, resulting in movement of potassium out of the cell. E. A time when voltage-gated sodium channels open rapidly, resulting in movement of sodium into the cell.