Podcast
Questions and Answers
The __________ is described as two strands of actin molecules wrapped together.
The __________ is described as two strands of actin molecules wrapped together.
thin filament
Which of the following happens as actin and myosin filaments slide past each other during muscle contraction?
Which of the following happens as actin and myosin filaments slide past each other during muscle contraction?
- Both actin and myosin filaments shorten.
- Either actin or myosin filaments shorten, but not both at the same time.
- Myosin filaments shorten, while actin filaments do not.
- Neither actin nor myosin filaments shorten. (correct)
- Actin filaments shorten, while myosin filaments do not.
Which of the following statements about the 'heads' of the myosin molecules is true?
Which of the following statements about the 'heads' of the myosin molecules is true?
- They form permanent links with actin filaments.
- None of these are true statements.
- They can attach to different sites on the actin filament. (correct)
- They allow the myosin filaments to wrap around each other.
- They straighten the myosin filaments.
Muscle contractions are initiated by the binding of __________ to __________.
Muscle contractions are initiated by the binding of __________ to __________.
During muscle contractions, cross-bridges form between the _________ and the __________.
During muscle contractions, cross-bridges form between the _________ and the __________.
Which of the following is the site of ATP binding and hydrolysis?
Which of the following is the site of ATP binding and hydrolysis?
During contraction of a muscle, calcium ions bind to the __________.
During contraction of a muscle, calcium ions bind to the __________.
The bond between the active site on actin and the myosin head is broken when an __________.
The bond between the active site on actin and the myosin head is broken when an __________.
The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions and ATP are present.
The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions and ATP are present.
An action potential causes calcium ions to diffuse from the ________ into the ________.
An action potential causes calcium ions to diffuse from the ________ into the ________.
Which of the following best describes the role of Ca2+ in muscle contraction?
Which of the following best describes the role of Ca2+ in muscle contraction?
Which of the following is not a filamentous protein?
Which of the following is not a filamentous protein?
An action potential enters the depths of a muscle fiber by way of __________.
An action potential enters the depths of a muscle fiber by way of __________.
Which structure do the calcium ions bind to when muscle contraction is initiated?
Which structure do the calcium ions bind to when muscle contraction is initiated?
Cross-bridges form between the __________ and the __________.
Cross-bridges form between the __________ and the __________.
Which of the following is not an example of an autonomic receptor?
Which of the following is not an example of an autonomic receptor?
Flashcards are hidden until you start studying
Study Notes
Muscle Contraction Basics
- Thin filament consists of two strands of actin molecules twisted together.
- During muscle contraction, neither actin nor myosin filaments shorten; they slide past each other.
Myosin Molecule Characteristics
- Myosin heads attach to various sites on actin filaments, allowing for flexibility.
- Myosin is the site of ATP binding and hydrolysis, essential for muscle movement.
Calcium's Role in Muscle Contraction
- Calcium ions initiate contractions by binding to troponin, leading to changes that allow myosin heads to attach to actin.
- An action potential prompts calcium ion release from the sarcoplasmic reticulum into the sarcoplasm.
Cross-Bridge Formation
- Cross-bridges form between myosin heads and actin filaments during contraction.
- The connection between the active site on actin and the myosin head is disrupted when an ATP molecule binds to the myosin head, facilitating muscle relaxation.
Filamentous and Non-Filamentous Proteins
- Troponin is not considered a filamentous protein; it functions differently within muscle contraction processes.
T Tubules
- An action potential travels into muscle fibers via T tubules, helping coordinate contraction.
Reflex Mechanisms
- The response to increased body temperature involving thermoreceptors and sweat glands exemplifies a reflex mechanism that maintains homeostasis in the body.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
