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A receptor synthesized with an erroneous amino acid sequence
is sent via fast anterograde transport to its axonal destination.
If you want to find the original site of error, which organelle
would you elect to observe?
A. Free polysome
B. Golgi apparatus
C. Mitochondria
D. Rough endoplasmic reticulum - ANSWER-A - Incorrect. Free
polysomes, or non-membrane-bound ribosomes, are the site
of peripheral protein (e.g. microtubules, neurofilaments)
synthesis.
B - Incorrect. Golgi apparatus is the place to which integral
proteins are sent for modification after synthesis.
C - Incorrect. Mitochondria, the cell's "powerhouses," are
important energy sources to fuel cellular transport but will not
reveal underlying causes of errors in protein synthesis.
,D - Correct. The rough endoplasmic reticulum, or
membrane-bound ribosomes, is the site of integral protein
(e.g., receptors, enzymes, ion channels) synthesis; such
proteins are destined for membrane insertion and travel via fast
transport.
Which of the following are involved in regulating
neurotransmission via
excitation-secretion
coupling?
A. Voltage-sensitive sodium
channels
B. Voltage-sensitive calcium
channels
C. Both A
and B
D. Neither A nor B - ANSWER-A - Partially
correct.
B - Partially
correct.
C - Correct. Propagation of an action potential to the axon
terminal is mediated by voltage-sensitive sodium channels.
Influx of sodium through voltagesensitive sodium channels at
the axon terminal leads to opening of voltagesensitive calcium
,channels, also at the axon terminal. Influx of calcium through
the open voltage sensitive calcium channels leads to docking
of synaptic vesicles and secretion of neurotransmitter into the
synapse. D - Incorrect.
Agonists cause ligand-gated ion channels to:
A. Open wider
B. Open for longer duration of time
C. Open more frequently
D. A and B
E. A and C - ANSWER-A - Incorrect. Agonists do not cause
ligand-gated receptors to open wider.
B - Incorrect. Agonists do not cause ligand-gated receptors to
open for longer durations of time.
C - Correct. Agonists cause ligand-gated ion channels to open
more frequently.
D - Incorrect.
E - Incorrect.
Presynaptic reuptake transporters are a major method of
inactivation for which of the following? A. Serotonin
B. Serotonin and GABA
C. Serotonin, GABA, and histamine
D. Serotonin, GABA, histamine, and neuropeptides - ANSWER-
A - Partially correct.
, B - Correct. Both monoamines such as serotonin and amino
acid neurotransmitters such as GABA are inactivated primarily
via presynaptic transporters.
C - Incorrect. Histamine does not have a known presynaptic
reuptake transporter and is instead inactivated via enzymatic
degradation.
D - Incorrect. Histamine and neuropeptides do not have
known presynaptic reuptake transporters. Histamine is
inactivated enzymatically and neuropeptides are inactivated by
diffusion, sequestration, and enzymatic destruction.
A neuron is infected with a toxin and causes a rather sudden
inflammatory reaction. You detect a high concentration of
cytokines in the surrounding area. Which process has taken
place?
A. Necrosis
B. Synaptogenesis
C. Excitotoxicity
D. Apoptosis
E. Neurogenesis - ANSWER-A - Correct. Necrosis is the neural
selection process in which a cell is poisoned, suffocated, or
otherwise destroyed by a toxin after which the cell explodes
and causes an inflammatory reaction. B - Incorrect.
Synaptogenesis is the process of forming synapses.