1. The plasma membrane of rod and cone cells are
a) At resting potential in the dark and deploarized in thelight
b) At resting pootential in the dark and hyperpolarized in thelight
c) Depolarized in the dark and hyperpolarized in the light
d) Hyperpolarized in the dark and at resting potential in thelight
e) Hyperpolarized in the dark and depolarized in the light
2. The equilibrium potential of K+ ions in nerve cells is about-90mV. The membrane potential of a typical nerve cells at rist is-70mV. Therfore
a) Increasing the permeability of a resting neuronal membrane toK+ ions will increase the membrane potential (that is, make it morenegative, inside with respcect to outside)
b) In nerve cells at rest, there is a net diffusion of K+ ionsout of the cell
c) Increasing the membrane potential of a nerve cell would slowthe diffusion of K+ ions out of it.
d) K+ is not the only ion that is permeable at rest
e) All of the above
3. Which of the following is responsible for the replarizingphase of the action potential?
a) Voltage-gated Na+ channels are opened.
b) The Na+-K+ pump restores the ions to theri original restingstate.
c) The permeability to Na+ increases greatly.
d) ATPase destroys the energy supply that was maintaining theaction potential at its peak.
e) The permeability to K+ increases greatly while that to Na+decreases
4. The Relative refractory period of an axonm conincides withthe period of
a) Activation and inactivatioin of voltage-gated Na+channels
b) Increased Na+ flux into the cell
c) Increased K+ flux into the cell
d) Increased K+ flux out of the cell
e) Increased Na+ flux out of the cell
5. The plasma membranes of rod and cone cells are
a) At resting potential in the dark and epolarized in thelight
b) At resting potential in the dark and hyperpolarized in thelight
c) Depolarized in the dark and hyperoplarized in the light
d) Hyperpolarized in the dark and tat resing potential in thelight
e) Hyperpolarized in the dark and depolarized in the light
