Human Anatomy and Physiology : Help with Sarcomere Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #342 : Systems Physiology

Which specific protein of troponin is responsible for attaching the troponin complex to tropomyosin?

Possible Answers:

Troponin T

Troponin C

Troponin I

Troponin A

Correct answer:

Troponin T

Explanation:

Troponin is a complex of three globular regulatory proteins (T, C, and I). Troponin is essential to the contraction of skeletal and cardiac muscle, but is not involved in the contraction of smooth muscle. Troponin T (think of: T for tropomyosin) binds to tropomyosin creating the troponin-tropomyosin complex, which helps to position tropomyosin onto actin. Troponin I (think of I for inhibition) binds actin, holding the actin-tropomyosin complex in place. This inhibits the myosin heads from binding their binding sites on actin. Lastly, troponin C (think of C for calcium) is responsible for binding calcium. This step is allows for the interaction of actin and myosin, thus activating the muscle for contraction.

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