PHYSIOLOGY
GENERAL PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Actin and troponin
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Myosin and Tropomyosin
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Actin, tropomyosin, and troponin
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Actin and myosin
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Detailed explanation-1: -The thin filament consists of actin, tropomyosin (Tm), and troponin (Tn) in 7:1:1 stoichiometry, and Tn is composed of three subunits: troponin C (TnC), the Ca2+-binding regulatory subunit; troponin I (TnI), the inhibitory subunit; and troponin T (TnT), the Tm-binding subunit.
Detailed explanation-2: -All muscles contain thin filaments (diameter of 6–10 nm) that consist of actin, tropomyosin (Tm), and troponin (Tn) in a 7:1:1 stoichiometry (Figure 1).
Detailed explanation-3: -Troponin and tropomyosin are regulatory proteins that help to regulate the interaction between actin and myosin filaments. The binding of the myosin heads to the muscle actin is a highly regulated process.
Detailed explanation-4: -Troponin (Tn) is the calcium-sensing protein of the thin filament.
Detailed explanation-5: -Thin filaments are a polymer of actin with tightly bound regulatory proteins troponin and tropomyosin (Fig. 39.4).