Dr. Brainy creates a nerve cell that is only permeable to Caesium ions (Cs+1) at rest. She measures that the concentration of Caesium is 400mM outside the cell and only 50 mM inside the cell. She calculates the Equilibrium potential for Cs+1 (Ecs) to be +35 mV. If the cell is only permeable to Cs, the resting membrane potential will be: +58 mV 0 mV +35 mV -58 mV

factors responsible for a negative resting membrane potential include: check all that apply:   a. Na K pump  b. different carrier proteins  c. uneven distribution of ions  d. difference in permeability of ions  e. high potassium concentration in ECF

Show a complete circuit diagram of the model of the neuron using the specific numerical values for each component: potassium ion concentration outside: 4.0 mmol/L potassium ion concentration inside: 77.5 mmol/L

Conditions: [Na+] outside = .3 mM [Na+] inside the presynaptic cell = .01 mM [dopamine] inside = .5 mM [dopamine] outside = .001 mM ΔGinward = RT ln [X] inside/[X] outside + z F Vm F = 23,000 cal/mol  V R = 1.987 cal/ mol K Membrane potential is .07 V Temperature is 273 K   Using the information above and image please answer these questions :     Is the concentration of sodium higher on the outside or the inside of the presynaptic cell?          Would the movement of sodium be active or passive moving OUT of the presynaptic cell?  SHOW your work.

The concentration of potassium ions inside a nerve cell membrane is higher than the concentration of sodium ions outside the mem-brane, yet the inside of the membrane (where the cation concentra-tion is higher) is negative to the outside. Explain this observation in terms of permeability properties of the membrane.

Three currents are produced by a 56 mV depolarization leading to an action potential in a squid axon membrane during a voltage clamp experiment as shown. What is the mechanism underlying the capacitive current? 56 mV Depolarization Capacitative current Late current Early current Time (ms) Opening of Na* channels Current due to the Na/K* pump O Neutralization of the charge on the membrane Opening of K channels Membrane Membeane current imA/cm potential (mV)

A membrane potential (Vm) labeled axis on the graph In the graph draw the phases of the action potential Include the channels involved and when they open and close matching them to the Vm Indicate the periods in which the action potential can or cannot occur

Place the following events in chronological order from 1-8: Nat enters the cell, and depolarization occurs to approximately +30 mV. The voltage across the cell membrane is -70 mV, the resting membrane potential. Upon reaching the peak of the action potential, the VG Nat channels are inactivated by the closing of their inactivation gate and the activation gate of each VG K channel opens. VG K channels close by the closing of their activation gate, and the resting membrane potential is gradually restored. An excitatory post-synaptic potential depolarizes the membrane to threshold and the activation gate of VG Nat channels open. Upon returning to the resting membrane potential, VG Na channels are reset by opening of the inactivation gate and the closing of the activation gate. VG K+ channels are slow to close, resulting in an excess of K* efflux and hyperpolarization. Depolarization occurs as K+ flows out of the cell.

Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+.   The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV.   Which item best represents the forces and fluxes for a membrane potential of +40 mV?

Consider the following three diagrams of a nerve cell membrane. They show resting potential, depolarization, and hyperpolarization. Figure out which one is which, then draw them in the order they occur in a cell that undergoes an action potential outside + Na* inside K* Na* Nat K Nat K Na potential: -80 mV outside + Na K* Na* inside Na+ K Nat Na* K+ potential: +30 mV outside Na Na Na Na* K+ inside K* Na* Kt potential: -70 mV