Active sites on actin become available for binding when (a) calcium binds to troponin. (b) troponin binds to tropomyosin. (c) calcium binds to tropomyosin. (d) actin binds to troponin.

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Answer 1

Textbook Question

Chapter 9, Problem 1RFT

Active sites on actin become available for binding when

(a) calcium binds to troponin.

(b) troponin binds to tropomyosin.

(c) calcium binds to tropomyosin.

(d) actin binds to troponin.

Expert Solution & Answer

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

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Students have asked these similar questions

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.

Given these events:(1) Calcium ions combine with tropomyosin.(2) Calcium ions combine with troponin.(3) Tropomyosin pulls away from actin.(4) Troponin pulls away from actin.(5) Tropomyosin pulls away from myosin.(6) Troponin pulls away from myosin.(7) Myosin binds to actin.

During muscular contraction, cross-bridges form between _____ and _____ . Multiple Choice a) myosin, tropomyosin b) myosin, troponin c) troponin, calmodulin d) actin, tropomyosin e) actin, myosin

Answer 2

Textbook Question

Chapter 9, Problem 1RFT

Active sites on actin become available for binding when

(a) calcium binds to troponin.

(b) troponin binds to tropomyosin.

(c) calcium binds to tropomyosin.

(d) actin binds to troponin.

Expert Solution & Answer

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

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Answer 3

Textbook Question

Chapter 9, Problem 1RFT

Active sites on actin become available for binding when

(a) calcium binds to troponin.

(b) troponin binds to tropomyosin.

(c) calcium binds to tropomyosin.

(d) actin binds to troponin.

Expert Solution & Answer

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

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Answer 4

Textbook Question

Chapter 9, Problem 1RFT

Active sites on actin become available for binding when

(a) calcium binds to troponin.

(b) troponin binds to tropomyosin.

(c) calcium binds to tropomyosin.

(d) actin binds to troponin.

Expert Solution & Answer

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

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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:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

Answer 8

Expert Solution & Answer

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

Answer 9

Expert Solution & Answer

Answer 10

Expert Solution & Answer

Answer 11

Summary Introduction

Introduction:

Muscles are made up of two main protein filaments namely, a thick filament that is made up of a protein called myosin and a thin filament that is composed of a protein known as actin. When these two filaments crossover one another in a row of repetitive events then muscle contraction takes place.

Answer 12

Answer to Problem 1RFT

Correct answer:

Thin filament consists of regulatory proteins called tropomyosin and troponin and the calcium ions binds with the troponin.

Answer 13

Explanation of Solution

Explanation for the correct answer:

Option (a) is given as calcium binds to troponin. The muscle contraction takes place in a series of steps. The cycle starts with electrical events in the sarcolemma. This accelerates the generation of calcium ions from the cisternae of the sarcoplasmic reticulum. The calcium ions then enter the zone of overlap. The next step involves binding of these calcium ions to troponin in the complex of troponin-tropomyosin. This alters the position and rolls the tropomyosin molecule away from the active sites present on the actin. This makes the active sites exposed for the formation of cross-bridges. Hence option (a) is correct.

Explanation for the incorrect answers:

Option (b) is given as troponin binds to tropomyosin. Troponin binds to the troponin-tropomyosin complex and rolls away from the tropomyosin complex. So, it is a wrong answer.

Option (c) is given as calcium binds to tropomyosin. Calcium binds to the troponin molecule instead of tropomyosin molecule. So, it is a wrong answer.

Option (d) is given as actin binds to troponin. Troponin binds to the calcium and makes actin sites exposed. So, it is a wrong answer.

Hence, option (b), (c) and (d) are incorrect.

Answer 14

Conclusion

Therefore, it can be concluded that calcium ions bind to the troponin and this troponin then binds to the troponin-tropomyosin complex, making active sites exposed during muscle contractions.

Answer 15

Ch. 9 - 1. Active sites on actin become available for...Ch. 9 - Prob. 2RFT Ch. 9 - Prob. 3RFT Ch. 9 - 4. Another name for a muscle that is a prime mover...Ch. 9 - Prob. 5RFT Ch. 9 - Prob. 6RFT Ch. 9 - 7. The theory that explains muscle contraction is...Ch. 9 - Prob. 8RFT Ch. 9 - Label the illustrations to the right as...Ch. 9 - Prob. 1RC

Active sites on actin become available for binding when (a) calcium binds to troponin. (b) troponin binds to tropomyosin. (c) calcium binds to tropomyosin. (d) actin binds to troponin.

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Answer to Problem 1RFT

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