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What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
- Ca$^{2+}$ binding to TnC shifts the tropomyosin-troponin complex, relieving inhibition and allowing muscle contraction to proceed. (correct)
- Ca$^{2+}$ binding to TnC strengthens the inhibition of muscle contraction by the tropomyosin-troponin complex.
- Ca$^{2+}$ binding to TnC causes dissociation of tropomyosin from actin filaments, preventing muscle contraction.
- Ca$^{2+}$ binding to TnC has no effect on the tropomyosin-troponin complex or muscle contraction.
What is the role of tropomyosin in muscle contraction?
What is the role of tropomyosin in muscle contraction?
- Tropomyosin binds lengthwise along actin filaments and, in striated muscle, is associated with a complex of three troponins, regulating the binding of myosin to actin. (correct)
- Tropomyosin blocks the binding of troponins to actin filaments, preventing muscle contraction.
- Tropomyosin directly binds to myosin to initiate muscle contraction.
- Tropomyosin is not involved in regulating muscle contraction.
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
- Shortening of both actin and myosin filaments
- Shortening of the sarcomere without any change in filament length (correct)
- Lengthening of the sarcomere without any change in filament length
- Lengthening of both actin and myosin filaments
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
What is the role of tropomyosin in muscle contraction?
What is the role of tropomyosin in muscle contraction?
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
Which component works in conjunction with troponin to regulate association of tropomyosin and troponins with actin filaments?
Which component works in conjunction with troponin to regulate association of tropomyosin and troponins with actin filaments?
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