BIO 264 EXAM 3 TESTED QUESTIONS
AND COMPLETE SOLUTIONS
◉ The movement of the troponin-tropomyosin complex requires
_______
Answer: Ca2+.
◉ The actin filament is a polymer formed from 300 to 400
globular subunits called ______
Answer: G-actin.
◉ A myofilament is the _________.
Answer: Protein strand composed of actin or myosin
◉ T tubules ________.
Answer: Conduct action potentials deep into the muscle cell
◉ A drug that interferes with the active transport of calcium ions
from the sarcoplasm back into the sarcoplasmic reticulum would
result in _______.
Answer: Contraction with no relaxation
,◉ Cardiac muscle cells are like skeletal muscle cells in that they
both ________.
Answer: have striations
◉ Predict the consequences of administration of a compound that
blocks the calcium channels on presynaptic motor neuron
terminals.
A. This should ultimately inhibit the release of acetylcholine
B. This should ultimately inhibit the muscle membrane from
depolarization
C. This should ultimately inhibit the release of calcium from the
sarcoplasmic reticulum
D. All of the above are correct answers
Answer: D. All of the above are correct answers
◉ Predict the consequences of administration of a compound that
inhibits acetylcholinesteras
Answer: The muscle will stay contracted
◉ Myofibrils are composed primarily of ________.
Answer: Actin and myosin
◉ Binding of ________ to myosin permits cross-bridge _____________
between actin and myosin.
Answer: ATP; detachment
,◉ The part of the sarcolemma that invaginates into the interior of
skeletal muscle fibers is the
Answer: T tubule system.
◉ Somatic motor neurons release the neurotransmitter _________ at
the neuromuscular junction.
Answer: Acetylcholine
◉ The gangster movies call a dead person a stiff, rigor mortis is
the proper name. How does this occur?
Answer: Without ATP, muscles remain fixed in their last state of
contraction.
◉ T tubules are invaginations of the ________.
Answer: Sarcolemma
◉ One cause of spastic paralysis might be ________.
Answer: Inhibition of acetylcholinesterase
◉ Somatic motor neurons release the neurotransmitter _________ at
the myoneural junction.
Answer: Acetylcholine
◉ Rigor mortis occurs after death because
, Answer: Cross-bridges form but can't release.
◉ Given these events:
(1) Acetylcholine is broken down into acetic acid and choline.
(2) Acetylcholine diffuses across the synaptic cleft.
(3) An action potential reaches the terminal branch of the motor
neuron.
(4) Acetylcholine combines with a ligand-gated ion channel.
(5) An action potential is produced on the muscle fiber's plasma
membrane.
Choose the arrangement that lists the events in the order they
occur at a neuromuscular junction.
Answer: 3,2,4,5,1
◉ The sites where a chemical substance is transmitted from the
presynaptic terminal of an axon to the postsynaptic membrane of
a muscle fiber are called ________.
Answer: Neuromuscular junctions
◉ Acetylcholine is released from the presynaptic terminal by the
process of _________.
Answer: Exocytosis
◉ Arrange the following list of biochemical events in the correct
sequence.
AND COMPLETE SOLUTIONS
◉ The movement of the troponin-tropomyosin complex requires
_______
Answer: Ca2+.
◉ The actin filament is a polymer formed from 300 to 400
globular subunits called ______
Answer: G-actin.
◉ A myofilament is the _________.
Answer: Protein strand composed of actin or myosin
◉ T tubules ________.
Answer: Conduct action potentials deep into the muscle cell
◉ A drug that interferes with the active transport of calcium ions
from the sarcoplasm back into the sarcoplasmic reticulum would
result in _______.
Answer: Contraction with no relaxation
,◉ Cardiac muscle cells are like skeletal muscle cells in that they
both ________.
Answer: have striations
◉ Predict the consequences of administration of a compound that
blocks the calcium channels on presynaptic motor neuron
terminals.
A. This should ultimately inhibit the release of acetylcholine
B. This should ultimately inhibit the muscle membrane from
depolarization
C. This should ultimately inhibit the release of calcium from the
sarcoplasmic reticulum
D. All of the above are correct answers
Answer: D. All of the above are correct answers
◉ Predict the consequences of administration of a compound that
inhibits acetylcholinesteras
Answer: The muscle will stay contracted
◉ Myofibrils are composed primarily of ________.
Answer: Actin and myosin
◉ Binding of ________ to myosin permits cross-bridge _____________
between actin and myosin.
Answer: ATP; detachment
,◉ The part of the sarcolemma that invaginates into the interior of
skeletal muscle fibers is the
Answer: T tubule system.
◉ Somatic motor neurons release the neurotransmitter _________ at
the neuromuscular junction.
Answer: Acetylcholine
◉ The gangster movies call a dead person a stiff, rigor mortis is
the proper name. How does this occur?
Answer: Without ATP, muscles remain fixed in their last state of
contraction.
◉ T tubules are invaginations of the ________.
Answer: Sarcolemma
◉ One cause of spastic paralysis might be ________.
Answer: Inhibition of acetylcholinesterase
◉ Somatic motor neurons release the neurotransmitter _________ at
the myoneural junction.
Answer: Acetylcholine
◉ Rigor mortis occurs after death because
, Answer: Cross-bridges form but can't release.
◉ Given these events:
(1) Acetylcholine is broken down into acetic acid and choline.
(2) Acetylcholine diffuses across the synaptic cleft.
(3) An action potential reaches the terminal branch of the motor
neuron.
(4) Acetylcholine combines with a ligand-gated ion channel.
(5) An action potential is produced on the muscle fiber's plasma
membrane.
Choose the arrangement that lists the events in the order they
occur at a neuromuscular junction.
Answer: 3,2,4,5,1
◉ The sites where a chemical substance is transmitted from the
presynaptic terminal of an axon to the postsynaptic membrane of
a muscle fiber are called ________.
Answer: Neuromuscular junctions
◉ Acetylcholine is released from the presynaptic terminal by the
process of _________.
Answer: Exocytosis
◉ Arrange the following list of biochemical events in the correct
sequence.
