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

Want to see more full solutions like this?

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.

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!

Students have asked these similar questions

What role (function) does calcium have within a muscle fiber? a. trigger muscle potentials along t-tubules b. trigger contraction by causing the formation of cross bridges c. trigger exocytosis of ACh across the synaptic space d. trigger action potentials along axons e. open voltage gates within the sarcoplasmic reticulum 2. Which of the following are regulatory proteins that allow a muscle fiber to contract when calcium is present? (select all that apply) dystrophin troponin myosin tropomyosin actin 3. During this phase of an action potential, potassium ions exit the cell through voltage gated potassium channels. a. depolarization b. repolarization c. glycolysis d. cross bridge formation

When a skeletal muscle cell contracts and the muscle shortens, a. the position of an actin molecule relative to a myosin molecule does not change. b. myosin heads generate a single power stroke. c. the actin ATPase allows the actin molecule to swivel. d. the actin molecule swivels during the power stroke e. some myosin heads are forming crossbridges as others are releasing them.

The function of Ca2+ in skeletal muscle contraction is toa. cause an allosteric change in myosin so it detaches from actin.b. provide the energy necessary for the movement of the cross-bridge.c. expose the myosin-binding sites on the thin filaments.d. bind to tropomyosin.e. do a and c only.

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.

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 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.

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 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.