Question

2. Explain how the resting membrane potential of a neuron is established by a. Listing the important ions/molecules that contribute to the establishment of the membrane potential (there are 4) Describing which direction the ions/molecules flow (if at all; in or out of the cell?) Telling me which one of the ions/molecules is the MOST important for establishing the resting membrane potential and WHY b. c. Explaining how this ONE important ion/molecule flows through the membrane by describing the opposing forces imposed on it (one force pulls it into the cell, one pulls it out). What is the NET flow of this ion once the resting membrane potential is established despite the opposing forces? d. e. You may draw a figure to answer parts a, b and e. Be sure your figure is clearly labeled (ex: inside and outside the neuron) Parts c and d require a written explanation.

Answer 1

2.

a. K⁺, Na⁺, Cl^-, organic anions like proteins

b. RMP is established by importing 2K+ ion into ECF and exporting 3Na+ into the ICF. because neuron always needs K+.

c. K⁺ because there are many K+ leak channel compared to Na+ leak channel. so membrane potential can be established.

d. K+ ions are exported out again to keep the membrane at RMP. so it works according to the concentration gradient. so when according to concentration gradient the K+ ion flows the leak channel pull the K+ ion. but when the Na+/K+ pump works it pushes the K+ into the cell, so this pump consumes ATP. so it is called an active transport of Na+/K+.

e. Pump imports 2K+ ion into ECF and exporting 3Na+ into the ICF.