Pufferfish (Fugu) are a delicacy in Japan, but must be cleaned very carefully as their liver contains tetrodotoxin which blocks voltage-gated Na+ channels. Imagine you are testing for the presence of this toxin using a neuron in a dish. You apply an electrical stimulus to the neuron that should produce an action potential. What will you observe if tetrodotoxin levels are high enough to block the
neuron's voltage-gated Na+ channels?
A. The neuron will exhibit a slow depolarization even before the stimulus is applied and then a normal action potential.
B. The neuron will exhibit a slow hyperpolarization even before the stimulus is applied.
C. The neuron will show a normal resting potential, but not exhibit depolarization when the stimulus is applied.
D. The neuron will depolarize and exhibit rapid depolarization, but will not repolarize.
E. The neuron will depolarize normally, but then become hyperpolarized such that the membrane potential is much lower than usual.
C. The neuron will show a normal resting potential, but not exhibit depolarization when the stimulus is applied.
You might also like to view...
Discuss the role of turgor in the crisp lettuce purchased at the grocery store looking much limper by
the time it gets home. What will be an ideal response?
The fact that energy transformations increase the amount of entropy is the basis of which of the following?
a. cell theory b. first law of thermodynamics c. second law of thermodynamics d. oxidation-reduction reactions
A fetus is
(a) a newborn pig. (b) a newborn human. (c) an unborn mammal. (d) all of the above.
A(n) __________ consists of hardened parts inside the body.
Fill in the blank(s) with the appropriate word(s).