BIO 264 ALL TEST PAPER QUESTIONS AND
ANSWERS SURE A+
✔✔One cause of spastic paralysis might be ________. - ✔✔Inhibition of
acetylcholinesterase
✔✔Somatic motor neurons release the neurotransmitter _________ at the myoneural
junction. - ✔✔Acetylcholine
✔✔Rigor mortis occurs after death because - ✔✔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. - ✔✔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 ________. -
✔✔Neuromuscular junctions
✔✔Acetylcholine is released from the presynaptic terminal by the process of
_________. - ✔✔Exocytosis
✔✔Arrange the following list of biochemical events in the correct sequence.
1.An action potential is conducted deep into the muscle fiber by the T tubule.
2.Calcium ions bind to troponin.
, 3.The membranes of the sarcoplasmic reticulum become more permeable to calcium
ions.
4.Calcium ions diffuse into the sarcoplasm around the myofibril.
5.The troponin-tropomyosin complex moves exposing active sites. - ✔✔1, 3, 4, 2, 5
✔✔Curare blocks acetylcholine receptors at the motor end plate. This would result in
_______. - ✔✔Inability of the muscle fiber to respond to nervous stimulation
✔✔Subunits of skeletal muscle cells that are composed of sarcomeres are called -
✔✔Myofibrils.
✔✔In excitation-contraction coupling, _________. - ✔✔Myosin heads bind to exposed
active sites on actin
✔✔Predict the consequences of administration of a compound that binds to
acetylcholine receptors in a neuromuscular junction but does not open them. - ✔✔The
muscle membrane will not reach threshold
✔✔Given these events:
(1) sarcoplasmic reticulum releases Ca2+
(2) sarcoplasmic reticulum takes up Ca2+
(3) Ca2+ diffuse into myofibrils
(4) action potential moves down the T tubule
(5) sarcomere shortens
(6) muscle relaxes
Choose the arrangement that lists the events in the order they occur following a single
stimulation of a skeletal muscle cell. - ✔✔4,1,3,5,2,6
✔✔The sarcolemma is the _________. - ✔✔Cell membrane of a muscle fiber
✔✔What is a cross-bridge? - ✔✔The combination of myosin heads with active sites on
actin molecules
✔✔Arrange the following steps for contraction in the correct sequence.
(1) The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.
(2) Thin filaments are pulled over the thick filaments.
(3) Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.
(4) The impulse arrives at the synapse and travels through the transverse tubules.
(5) The muscle fiber shortens and contracts.
(6) Tropomyosin molecules bind to exposed active sites, linking actin and myosin -
✔✔4, 1, 3, 6, 2, 5
ANSWERS SURE A+
✔✔One cause of spastic paralysis might be ________. - ✔✔Inhibition of
acetylcholinesterase
✔✔Somatic motor neurons release the neurotransmitter _________ at the myoneural
junction. - ✔✔Acetylcholine
✔✔Rigor mortis occurs after death because - ✔✔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. - ✔✔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 ________. -
✔✔Neuromuscular junctions
✔✔Acetylcholine is released from the presynaptic terminal by the process of
_________. - ✔✔Exocytosis
✔✔Arrange the following list of biochemical events in the correct sequence.
1.An action potential is conducted deep into the muscle fiber by the T tubule.
2.Calcium ions bind to troponin.
, 3.The membranes of the sarcoplasmic reticulum become more permeable to calcium
ions.
4.Calcium ions diffuse into the sarcoplasm around the myofibril.
5.The troponin-tropomyosin complex moves exposing active sites. - ✔✔1, 3, 4, 2, 5
✔✔Curare blocks acetylcholine receptors at the motor end plate. This would result in
_______. - ✔✔Inability of the muscle fiber to respond to nervous stimulation
✔✔Subunits of skeletal muscle cells that are composed of sarcomeres are called -
✔✔Myofibrils.
✔✔In excitation-contraction coupling, _________. - ✔✔Myosin heads bind to exposed
active sites on actin
✔✔Predict the consequences of administration of a compound that binds to
acetylcholine receptors in a neuromuscular junction but does not open them. - ✔✔The
muscle membrane will not reach threshold
✔✔Given these events:
(1) sarcoplasmic reticulum releases Ca2+
(2) sarcoplasmic reticulum takes up Ca2+
(3) Ca2+ diffuse into myofibrils
(4) action potential moves down the T tubule
(5) sarcomere shortens
(6) muscle relaxes
Choose the arrangement that lists the events in the order they occur following a single
stimulation of a skeletal muscle cell. - ✔✔4,1,3,5,2,6
✔✔The sarcolemma is the _________. - ✔✔Cell membrane of a muscle fiber
✔✔What is a cross-bridge? - ✔✔The combination of myosin heads with active sites on
actin molecules
✔✔Arrange the following steps for contraction in the correct sequence.
(1) The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.
(2) Thin filaments are pulled over the thick filaments.
(3) Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.
(4) The impulse arrives at the synapse and travels through the transverse tubules.
(5) The muscle fiber shortens and contracts.
(6) Tropomyosin molecules bind to exposed active sites, linking actin and myosin -
✔✔4, 1, 3, 6, 2, 5
