What is the mechanism by which voltage-gated channels open in response to voltage changes? Choose the best answer: (a) Voltage changes cause release of ligand (b) Voltage changes shift the receptor from the inactivated to active state (c) Charged residues in the channel lead to a conformation change (d) Voltage changes lead to increased force from ions attempting to pass through (e) Voltage changes increase ion channel expression I wish to select answer (c), but I am not sure it is the best answer compared with (b) and (d). Thus I wish to seek your expertise advice.

The voltage-gated calcium channel is a protein that is imbedded and spans the lipid membrane to allow the movement of calcium into the axon terminal. What is theappropriate amino acid configuration of this channel that allows this movement to happen?Select one:O a. non-polar amino acids on the interior surface and polar on the exterior surfaceO b. polar amino acids on the interior surface and polar on the exterior surfaceO c. non-polar amino acids on the exterior surface and polar on the interior surfaceO d. non-polar amino acids on the interior surface and non-polar on the exterior surface

1) The olfactory receptor neurons in frogs resemble those of mammals, in that they express olfactory receptors that are coupled to a G protein. When the G protein is activated, it activates an adenylyl cyclase to produce cAMP, which then opens cyclic-AMP gated cation channels in the plasma membrane. The opening of these channels depolarizes the membrane, leading to the production of an action potential. Your friend is interested in why neurons stop responding to an odor after prolonged exposure to it, a process called adaptation. He has conducted experiments examining the depolarization of the olfactory receptor neuron, the binding of odorant to the receptor, the activation of the G protein, the levels of CAMP in the cell, and the phosphorylation of adenylyl cyclase. His results are summarized in Table 1. depolarization of neuron? odorant binding to receptor? activation of the G protein? CAMP levels in the cell? adenylyl cyclase phosphorylation? no odor no no no low no Table 1 brief…

The top panel (a) of this figure shows the graded potential change (far right, upper, electrical trace) that results from ligand binding to the ligand gated Na+ channel. The bottom panel of this figure (b) shows a graded potential change (far right, lower, electrical trace) that results from ligand binding to a ligand gated Cl- channel. From this trace you know (Vm = -70 mV) 1. ECl- is -70 mV 2. ECl- is more negative than -70 mV (i.e., -80 mV) 3. ECl- is more positive than -70 mV (i.e., -60 mV)