Question 1

What is the correct sequence of events in cross-bridge cycling?

Accepted Answer

A)  Myosin cross-bridge binds to actin,the powerstroke moves the thin filament relative to the thick filament,ATP binds to myosin and cross-bridge detachment occurs,ATP is hydrolyzed and the myosin head is "cocked"
B)  The powerstroke moves the thin filament relative to the thick filament,myosin cross-bridge binds to actin,ATP binds to myosin and cross-bridge detachment occurs,ATP is hydrolyzed and the myosin head is "cocked"
C)  Myosin cross-bridge binds to actin,ATP is hydrolyzed and the myosin head is "cocked," the powerstroke moves the thin filament relative to the thick filament,ATP binds to myosin and cross-bridge detachment occurs
D)  Myosin cross-bridge binds to actin,ATP binds to myosin and cross-bridge detachment occurs,the powerstroke moves the thin filament relative to the thick filament,ATP is hydrolyzed and the myosin head is "cocked"
E)  These events can occur in any sequence without affecting muscle function.F) A) and B)
G) All of the above

Question 2

The fact that a quarterback can throw a football at approximately 50 miles per hour means that the muscles powering this throw must also be shortening at 50 miles per hour.

Accepted Answer

A) True 
 B)False

Question 3

When experimentally applying alpha-bungarotoxin to a muscle,you find that it does not contract when the motor neuron leading to it is electrically stimulated.Knowing that this toxin blocks acetylcholine receptors,what can you conclude about the failure to contract?

Accepted Answer

A)  A contraction fails to occur because this toxin prevents cross-bridge formation and thereby directly prevents contraction.
B)  A contraction fails to occur because acetylcholine is not released from the motor neuron.
C)  A contraction fails to occur because this toxin directly prevents calcium ion release from intracellular stores.
D)  A contraction fails to occur because an action potential is not generated in the muscle cell.
E)  A contraction fails to occur because neurotransmitter release by the motor neuron is blocked at the neuromuscular junction.F) None of the above
G) B) and E)

Question 4

A new species of mouse is discovered that can sprint extraordinarily rapidly but also fatigues quickly.How would you expect its muscle composition to compare to that of an ordinary house mouse?

Accepted Answer

A)  more slow oxidative fibers
B)  more slow glycolytic fibers
C)  more fast oxidative fibers
D)  more fast glycolytic fibers
E)  fewer fast glycolytic fibersF) A) and D)
G) A) and C)

Question 5

A new muscle is found in an undiscovered species and your HYPERLINK "#" job is to classify the muscle type.When examined under a microscope there does not appear to be any straitions.When stimulated,muscle contraction time is very slow,around 30 seconds.When observed in a fully anesthetized specimen,the muscle is continuously contrating.What muscle type does this myster muscle most likely belong to?

Accepted Answer

A)  Cardiac muscle
B)  Skeletal muscle
C)  Smooth muscleD) All of the above
E) A) and B)

Question 6

Which protein contains a binding site for ATP?

Accepted Answer

A)  troponin
B)  myosin
C)  tropomyosin
D)  myelin
E)  All muscle proteins must have an ATP binding sitE.F) B) and D)
G) C) and E)

Question 7

Imagine you have extracted myosin molecules from both fast and slow twitch muscle fibers and are measuring the rate at which these proteins hydrolyze ATP.What would these relative rates of ATP hydrolysis be?

Accepted Answer

A)  fast twitch fiber > slow twitch fiber
B)  slow twitch fiber > fast twitch fiber
C)  slow twitch fiber = fast twitch fiberD) B) and C)
E) None of the above

Question 8

The acetylcholine receptor is a ligand-gated channel that produces

Accepted Answer

A)  Repolarization by activating second messenger systems within the muscle fiber.
B)  Depolarization by allowing K+ ions to leave the muscle fiber.
C)  Depolarization by allowing Cl- ions to enter the muscle fiber.
D)  Depolarization by allowing Na+ ions to enter the muscle fiber.
E)  Hyperpolarization by allowing Na+ ions to exit the muscle fiber.F) B) and E)
G) A) and D)

Question 9

For the hierarchy of skeletal muscle organization,which accurately lists the order of structures from "small" to "big"?

Accepted Answer

A)  sarcomere,myofibril,muscle fiber,motor unit
B)  myofibril,muscle fiber,sarcomere,motor unit
C)  motor unit,myofibril,muscle fiber,sarcomere
D)  motor unit,sarcomere,muscle fiber,myofibril
E)  None of the choices are correct.F) B) and D)
G) B) and E)

Question 10

What structural component in skeletal and cardiac muscle conducts action potentials from the outer surface of the muscle fiber inside to the myofibrils?

Accepted Answer

A)  actin
B)  tropomyosin
C)  troponin
D)  transverse tubule
E)  None of thesE.F) C) and E)
G) A) and E)

Exam 34: Muscular-Skeletal Systems

A new species of mouse is discovered that can sprint extraordinarily rapidly but also fatigues quickly.How would you expect its muscle composition to compare to that of an ordinary house mouse?

Correct Answer
verified

Correct Answer
verified

Which protein contains a binding site for ATP?

Correct Answer
verified

For the hierarchy of skeletal muscle organization,which accurately lists the order of structures from "small" to "big"?

Correct Answer
verified

Imagine you have extracted myosin molecules from both fast and slow twitch muscle fibers and are measuring the rate at which these proteins hydrolyze ATP.What would these relative rates of ATP hydrolysis be?

Correct Answer
verified

What structural component in skeletal and cardiac muscle conducts action potentials from the outer surface of the muscle fiber inside to the myofibrils?

Correct Answer
verified

When experimentally applying alpha-bungarotoxin to a muscle,you find that it does not contract when the motor neuron leading to it is electrically stimulated.Knowing that this toxin blocks acetylcholine receptors,what can you conclude about the failure to contract?

Correct Answer
verified

The acetylcholine receptor is a ligand-gated channel that produces

Correct Answer
verified

The fact that a quarterback can throw a football at approximately 50 miles per hour means that the muscles powering this throw must also be shortening at 50 miles per hour.

Correct Answer
verified

What is the correct sequence of events in cross-bridge cycling?

Correct Answer
verified

Exam 34: Muscular-Skeletal Systems

A new species of mouse is discovered that can sprint extraordinarily rapidly but also fatigues quickly.How would you expect its muscle composition to compare to that of an ordinary house mouse?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which protein contains a binding site for ATP?

Correct AnswerverifiedShow Answer

For the hierarchy of skeletal muscle organization,which accurately lists the order of structures from "small" to "big"?

Correct AnswerverifiedShow Answer

Imagine you have extracted myosin molecules from both fast and slow twitch muscle fibers and are measuring the rate at which these proteins hydrolyze ATP.What would these relative rates of ATP hydrolysis be?

Correct AnswerverifiedShow Answer

What structural component in skeletal and cardiac muscle conducts action potentials from the outer surface of the muscle fiber inside to the myofibrils?

Correct AnswerverifiedShow Answer

When experimentally applying alpha-bungarotoxin to a muscle,you find that it does not contract when the motor neuron leading to it is electrically stimulated.Knowing that this toxin blocks acetylcholine receptors,what can you conclude about the failure to contract?

Correct AnswerverifiedShow Answer

The acetylcholine receptor is a ligand-gated channel that produces

Correct AnswerverifiedShow Answer

The fact that a quarterback can throw a football at approximately 50 miles per hour means that the muscles powering this throw must also be shortening at 50 miles per hour.

Correct AnswerverifiedShow Answer

What is the correct sequence of events in cross-bridge cycling?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified