1. Gap junctions may exhibit all of the following features except
a. the ability to pass small metabolites, including some second messengers.
b. the
... [Show More] ability to pass electrical current bidirectionally.
c. the ability to pass electrical current unidirectionally.
d. the ability to amplify small incoming electrical signals into large regenerative potentials.
e. the ability to synchronize the activity of populations of nerve cells.
Answer: d
Textbook Reference: Signaling Transmission at Electrical Synapses
2. The capability of a nerve terminal to rapidly and dramatically produce very large changes in calcium levels is most dependent on the
a. presence of calcium-selective ion channels.
b. enormous gradient of calcium across the membrane.
c. fact that calcium is a positively charged ion.
d. fact that calcium is a divalent cation.
e. All of the above are essential for producing large, rapid concentration changes.
Answer: b
Textbook Reference: Signaling Transmission at Chemical Synapses
3. Listed below are the individual events that make up chemical synaptic transmission.
1. Diffusion of transmitter across the synaptic cleft
2. Depolarization of the presynaptic terminal
3. Vesicle fusion with plasma membrane
4. Opening of voltage-gated ion channels
5. Activation of presynaptic, calcium-sensitive proteins
Which sequence represents the correct ordering of these events?
a. 1; 2; 3; 4; 5
b. 2; 4; 5; 3; 1
c. 2; 5; 4; 3; 1
d. 5; 4; 2; 3; 1
e. 1; 2; 4; 5; 3
Answer: b
Textbook Reference: Signaling Transmission at Chemical Synapses
4. Which characteristic is an accepted criterion for classifying a molecule as a
neurotransmitter?
a. It must be present in the presynaptic terminal.
b. It must be released in response to presynaptic electrical activity.
c. It must exert an effect on the postsynaptic cell.
d. All of the above
e. None of the above
Answer: d
Textbook Reference: Properties of Neurotransmitters
5. A scientist wishes to develop a new drug that prevents synaptic communication via neuropeptides but not small molecule neurotransmitters. Which mechanism would be a good target for his drug?
a. Disruption of axonal transport
b. Blocking of voltage-gated calcium channels
c. Disruption of V-SNARES
d. Blocking of voltage-gated sodium channels
e. Increasing levels of synaptosome
Answer: a
Textbook Reference: Properties of Neurotransmitters
6. Miniature end plate potentials, or MEPPs, are produced
a. at miniature end plates.
b. by the smallest axons.
c. in response to weak stimuli.
d. by the smallest neurotransmitters.
e. by spontaneous release of neurotransmitter.
Answer: e
Textbook Reference: Quantal Release of Neurotransmitters [Show Less]