During the contraction of a vertebrate skeletal muscle fiber, calcium ions A. break cross-bridges by acting as a cofactor in the hydrolysis of ATP. B. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. C. transmit action potentials from the motor neuron to the muscle fiber. D. spread action potentials through the T tubules.

Question

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Answer 1

Textbook Question

Chapter 39, Problem 1TYU

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

A. break cross-bridges by acting as a cofactor in the hydrolysis of ATP.
B. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
C. transmit action potentials from the motor neuron to the muscle fiber.
D. spread action potentials through the T tubules.

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

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Students have asked these similar questions

During the contraction of a vertebrate skeletal muscle fiber,calcium ions(A) break cross-bridges as a cofactor in hydrolysis of ATP.(B) bind with troponin, changing its shape so that the myosinbinding sites on actin are exposed.(C) transmit action potentials from the motor neuron to themuscle fiber.(D) spread action potentials through the T tubules.

In muscle cells, magnesium ions compete with calcium ions for binding sites on troponin molecules. If a person has too high a concentration of magnesium ions in the blood, magnesium ions can prevent calcium ions from binding troponin. A) What effect would this have on muscle contraction (strengthen, weaken, or no effect)? B) Use your knowledge of how muscle fibers contract to explain your answer in part A.

Myosin binds to actin, then bends. What is ATP needed for next? A. to pump the Ca++ “keys” back into the sarcoplasmic reticulum B. to replace the strap and cover the binding sites C. to give feedback to the neuron that contraction occurred D. to un-bind myosin from actin and re-set for another powerstroke.

Answer 2

Textbook Question

Chapter 39, Problem 1TYU

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

A. break cross-bridges by acting as a cofactor in the hydrolysis of ATP.
B. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
C. transmit action potentials from the motor neuron to the muscle fiber.
D. spread action potentials through the T tubules.

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

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Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Answer 3

Textbook Question

Chapter 39, Problem 1TYU

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

A. break cross-bridges by acting as a cofactor in the hydrolysis of ATP.
B. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
C. transmit action potentials from the motor neuron to the muscle fiber.
D. spread action potentials through the T tubules.

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

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Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Answer 4

Textbook Question

Chapter 39, Problem 1TYU

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

A. break cross-bridges by acting as a cofactor in the hydrolysis of ATP.
B. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
C. transmit action potentials from the motor neuron to the muscle fiber.
D. spread action potentials through the T tubules.

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Answer 5

Textbook Question

Answer 6

Textbook Question

Answer 7

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

Answer 8

Expert Solution & Answer

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.

Conclusion

Calcium ions play an important role in muscle contraction.

Answer 9

Expert Solution & Answer

Answer 10

Expert Solution & Answer

Answer 11

Summary Introduction

Introduction:

Skeletal muscles are voluntary muscles that are attached to bones by tendons. They help in the movement of various body parts in relation to each other.

Answer 12

Answer to Problem 1TYU

Correct answer:

During the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed. Therefore, option (B) is correct.

Answer 13

Explanation of Solution

Reasons for the correct statement:

Calcium ions (Ca²⁺) and actin binding proteins play an important role in muscle contraction and relaxation. Tropomyosin and troponin complex are proteins bound to thin filaments (actin filaments).

In muscle fiber at rest, a regulatory protein called tropomyosin covers the binding site of myosin protein, thereby preventing the interaction of actin and myosin.

The arrival of action potential causes release of calcium ions from the sarcoplasmic reticulum. The calcium ions bind to troponin complex causing the tropomyosin to shift away from the myosin-binding sites, thereby allowing the contraction of muscle.

Option (B) is given as “bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”.

As, “during the contraction of a vertebrate skeletal muscle fiber, calcium ions bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed”, it is the right answer.

Hence, option (B) is correct.

Reasons for the incorrect statements:

Option (A) is given as “break cross-bridges by acting as a cofactor in the hydrolysis of ATP”.

Calcium ions promote the formation of cross-bridges between actin and myosin, so it is a wrong answer.

Option (C) is given as “transmit action potentials from the motor neuron to the muscle fiber”.

The acetylcholine (neurotransmitter), but not the calcium ions transmits action potential from the motor neuron to the muscle fiber, so it is a wrong answer.

Option (D) is given as “spread action potential through the T tubules”.

The binding of acetylcholine to its receptors on the plasma membrane of a muscle fiber triggers action potential which spread through the T-tubules. The calcium ions do not spread action potential through the T-tubules, so it is a wrong answer.

Hence, options (A), (C), and (D) are incorrect.